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Table of contents
0. Introduction
Brief history
1. The Big Bang ... infinity in the largest and the smallest [Planck size]
2. Elementary particle ... E = mc 2 [gauge theory]
3. Stars ... Cosmic dawn [Cosmic background radiation]
4. Elements ... Alchemy is synthesis of a nuclus [nuclear energy]
5. Black hole … Birth and death of stars [Horizon of the event]
6. Dark matter ... an imperator of gravity [Neutralino]
7. The Milky Way Galaxy ... The formation of the microcosmos [Sagittarius A]
8. Solar system ... Order of the sky [gravity]
9. Earth ... Non-gas components of the solar system [chondrules]
10. Moon ... Giant Impact [tidal force]
11. The Sea ... Separation of materials on the Earth's surface [water]
12. Crater ... heavy bombardment of the Hadean eon [aerosol]
13. Earth's crust ... cooling of the earth's surface [interface]
14. Life ... Incidence or inevitability [hierarchy]
15. Small organic molecule ... The sky, the sea and the sea floor [Frontier molecular orbital theory]
16. Biopolymer … hydrothermal vent on the seafloor [Polymerization]
17. Carbon dioxide assimilation ... Growth of organic matter [Catalyst]
18. ATP ... Money of biochemical energy [activation energy]
19. RNA World ... Molecule able to replicate [ribozyme]
20. Plate tectonics ... Connect the sea and the sky [Aerosol]
21. Autocatalytic reaction ... Maintain non-equilibrium state [Chain reaction]
22. Cell membrane ... Separation of inside from outside [Chemiosmotic theory]
23. Protobiont organism ... Before common ancestry [LUCA]
24. Cell ... Life of independence [Molecular fossil]
25. Ribosome ... Mechanism to let genes function [nanomachine]
26. Geomagnetism ... Generation of super cold plume [Convection]
27. Virus ... Evolutionary leader [Reverse transcriptase]
28. Genome ... Time engraved in gene [molecular clock]
29. Photosynthesis ... Supply of oxygen and organic molecules [Stromatolite]
30. Banded iron formation ... Reduction of carbon dioxide [Oxidation]
31. Bacteria … Chaos of the evolution [diversification]
32. The super continent ... the driving force for the evolution of living things [Wilson cycle]
33. Snowball Earth ... faint young sun paradox [Phase transition]
34. Eukaryotic cells ... division of labor and its specialization [symbiosis theory]
35. Reproductive activity ... Men and women [sexuality]
36. Sensors ... To know the outside [receptor]
37. Multicellular organisms ... From assembly to organization [Self]
38. Collagen ... wrapping cells [differentiation]
39. Cambrian period ... a big explosion of evolution [eye]
40. Ordovician period ... The Sea of fertility [shells]
41. Silurian period ... Ozone layer [plant vascular bundle]
42. Devonian period ... Era of fish [bones]
43. Mountain ranges ... The time when Continents gather [Variscan orogeny movement]
44. Carboniferous period ... soil [metamorphose]
45. Permian Period ... Vertebrates advanced to the land [Amphibians]
46. Evolution of the genome ... Fundamentals of macroevolution [gene duplication]
47. Triassic period ... the largest continent [Pangea]
48. Jurassic period ... Hero of paleontology [Dinosaur]
49. Cretaceous period ... homothermal animals [homeostasis]
50. Gigantic meteorite ... Can we avoid natural catastrophe? [risk]
51. Placenta ... New reproductive strategy [retrotransposon]
52. Cenozoic era ... Animals which educate their children [mirror neurons]
53. Fruits ... co-existence and co-prosperity [seeds]
54. Prairie ... Cool climate and short life cycle [C4 plant]
55. Cenozoic era ... The continents changed currents in the ocean [Antarctic current]
56. Glacial Age ... Earth's cooling down [Messinian salinity crisis]
57. Milankovitch's cycle ... Periodic cooling and warming [Albedo effect]
58. Japan Sea ... Principle on birth of country land [Philippine's Sea plate]
59. Japan archipelago ... Four-way standoff of Plates [Fossa Magna]
60. Primates ... Expert of arboreal life [Oxytocin]
61. Australopithecus ... both humans and monkeys evolved from simians [body image]
62. Hominina ... Genealogy of the ruler [dopamine pathways]
63. Frontal cortex ... Mystery of its amazing development [NOTCH family]
64. Glacial Age ... Fluctuations of rotation and revolution of the Earth [positive feedback]
65. Fire ... the be-all-end-all solution [floresiensis]
66. Neanderthal people ... Brothers of the present human beings [ancient human genome]
67. Modern man ... simultaneous evolution of tool and language [Pinnacle point]
68. Language ... Direct control of vocal organs [FoxP2]
69. Out of Africa ... Ancestor with full of frontiers spirit [Wurm glaciation]
70. Tools … continuous upgrade of brain function [Microcephalin]
71. Race ... Migration at the global level [adaptive radiation]
72. Wurm glacial period ... the coldest Earth in human history [glacial lake]
73. The continental shelves … submerged history [Sunda land]
74. Oceanic flood ... Human beings lost the paradise [Younger Dryas]
75. Agriculture ... Understanding and application of ecosystems [Indo-European language family]
76. Walled city ... discoloration of the skin [Hypsithermal period]
77. The four great civilizations ... The cooling of the climate produced urban civilization [Pasturage]
78. Code ... the rise and fall of the ancient dynasty [Epic of Gilgamesh]
79. Letters ... Bronze is a nation [Code of Hammurabi]
80. History ... the basis of legitimacy [alphabet]
81. Philosophy ... discovery of individuality [Upanishad]
82. Empire ... Outstanding individuals [Hellenism]
83. Monotheism ... existence behind the complexity [holy book]
84. Map ... Separated by mountains, tied by the sea [compass]
85. The Global Empire ... Connecting the Edges of the Continent [gunpowder]
86. The closure of the country ... An aspect of a mature society [Japanese pirates]
87. The public ... the birth of a democracy [human rights]
88. Japanese people ... Where did we come from [Islands of the Far East]
89. Modern civilization ... Changes in progress in these 2 centuries [science]
90. Industrial Revolution ... Fire confined in iron [Power]
91. Chemistry ... to support high living standards [Molecules]
92. Agriculture ... Hunger makes civilization unstable [green revolution]
93. Medicine ... Managing the body and hygiene environment [Antibiotics]
94. War ... The Conquest by Europeans [atomic bombs]
95. Urbanization ... To realize an ideal life [Protocol]
96. Democracy ... To redefine lifestyle [salaried employee]
97. Internet ... Accumulated Information [LSI]
98. The future ... learning from history [Big History]
99. Industry for Virtual reality ... Cost to gain, store and analyze information [digital Self]
100. Individual and Society ... Freedom and Bondage [New Family]
101. Sustainability ... Personal-sized industry [Custom-made]
102. Environment ... The world of global warming [Recycle]
103. Interest rate ... Handling after collapse of bubble economy [oversaturation]
104. International order ... new hegemony of the world [Neo Sinocentrism]
105. 22th century ... recycling society [global recognition]
106. 23rd to 25th Century ... Control of the Global Environment [Shangri-La]
107. To the 30th century ... possibility of the destruction of civilization [Armageddon]
108. To a million of years after … The end of homo sapience [doomsday]
109. After humanity ... the end of the solar system [white dwarf]
110. Beyond our recognition ... the end of the Universe [thermal death]
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Simple chronology
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It was in 2003 that I determined to write this text, when I was 44 years old. Since I am a student of junior high school, I have been fascinated by the unusual idea, and interested in such as physics, mathematics, Bushido, and so on. With respect to the remarks of others, I was always wondering whether this is really true, "Is there no better way? Why do I act with this idea? Is the social structure correct that supports this idea? My thinking is not gathered, I was so-called indecision.
It is a good expression to be free from vacillation (Confucius). The questions before in my vacillated days are; What is said solution on the everyday problem, Problems on my specialty life science, their social significance, and difference between common sense and the "short term common sense", how to manage a group, how much emphasis should be given on hierarchical relationship to others, and so on. Recognizing that these problems are actually dependent on limited knowledge of individual, I can see through fog the structure of the society established based on those recognition.
If I arrange and systematize what I am thinking, I could have lived better. I write this text for my own wisdom of life. In order to write as a whole world, I should write about history along the whole time axis, of which I am aware (the genealogy of the universe). I should choose points to consider from the history to summarize various ideas (the genealogy of ten thousands of theories). I tried to keep the expression in everyday language. Would not it be ambiguous to make special words to express sophisticated thought? Will not you fall into a word game? I thought to express sophisticated thought by everyday written language.
Currently there is a convenient means of presentation such as the Internet. However, only when I put long story on a web page, it is hard to read, and is not to be read. Besides, considering from my own past experience, it will become troublesome for me to write it and probably, I will quit writing it. Therefore, I thought that it would be better to use an e-mail magazine. Every week, starting from the birth of the universe to modern themes, I will explain the history of the earth, life, and mankind from view point of contemporary perspectives. I emphasize the way of thinking, particularly from a scientific view, and write on the theme of understanding of human life. Proceed to the next even if it is not completed, and write a revised version after it has been completed. If I build up the history in repetitive way, I will be able to check my philosophy and the underlying knowledge as a whole. I can reconfirm my knowledge on the Internet. I feel that the world will spread when I find various information and ways of thinking from the related webpage in the network.
We all have large amounts of non-classified knowledge, and we always want to make them systematic. In school days, textbooks would have been a system of knowledge. When becoming a social worker, knowledge gained in daily life is fragmented, such as activities in the workplace, family and community, and professional knowledge on work, personal knowledge reading and hobbies. When fragments of knowledge are connected with unexpected links, or when I notice conceptual similarities between the fragments, my system of knowledge will expand slightly. I feel pleasure at such works.
Over the course of several versions, I began to think that it was assembled into new "myth = creation of the world". The hobby that I enjoy using e-mail magazines is, to make it a big history, the same as creation the world by utilizing the knowledge accumulated through science. As in the doctrine and philosophy of the former religion, this new "myth" needs to overlap as much as possible with every life, and it will be a tool to enrich the life and society as a whole.
Since this is work for myself only, I have an image like assembling a block puzzle according to the depth of my own recognition, to the extent that I knows. I will quote Kenzaburo Ohe’s words. "What I remember incorrectly was much worse than not being memorized was that my father told me, and I respected those who can incorporate in a daily conversation what they remembered from the book, as it is also interesting." (in “To the new people")
Unfortunately, there are some historical blank spaces in human knowledge. That part was filled with my hypothesis that seems plausible for me. I chose the hypothesis backing my confidence that I have solidified the philosophy of science. It is a statement that I want to continuously explain the history of the universe with a reasonable hypothesis.
About 13.8 billion years ago from now the Universe was born from a fluctuation of vacuum.
The Big Bang theory predicts a singular point in the beginning of the Universe. The size of the Universe at singular point is Planck size (10 exp (-44) seconds, 10 exp (-33 cm). exp means exponential in decimal). In Planck size, the energy conservation law and Einstein's theory of relativity, and so on, are broken due to Heisenberg's uncertainty principle. In this size, substances are generated or disappeared in vacuum (virtual particles).
Immediately after birth, the Universe rapidly expanded due to inflation by 10 exp (-34) seconds, and it became overcooled. The universe became extreme dense at high temperature with the energy released when the vacuum transformed from an unknown state before the universe to the present state. As inflation happened, the early Universe escaped from black hole formation by self-gravity. A vacuum has potential energy and tends to settle from a high energy state to a low state. The Universe born from the vacuum can lower the potential energy by the inflation.
The Universe which rapidly expanded by inflation extended the initial small fluctuation as it was. Currently, the fluctuation manifests itself in a slight non-uniformity of cosmic background radiation and unevenness in the distribution of galaxies. Small fluctuations were magnified by gravity, forming a large scale structure of the universe. The artificial satellite Planck to observe the cosmic background radiation was launched in 2009 and the results were opened in 2013. The composition of the universe was 4.9% for baryon, 26.8% for dark matter and 68.3% for dark energy. The Hubble constant was 67.15 ± 1.2 km/sec/Mpc, and the age of the Universe was 137.98 ± 0.37 billion years.
Galaxies are making groups on a scale of about 10 million light years. Galaxy groups and galaxy clusters (larger than group) further form a supercluster. The Milky Way Galaxy which the solar system resides belongs to the Virgo supercluster. Galaxy supercluster has size of several hundred million light years. In the Universe there is a large space where there is no galaxy. Examining the distribution of the galaxy, it turned out to be a foamy structure, and the galaxy turned out to be gathering around bubbles (space without galaxies. so called Void).
Sum of gravity of visible stellar matters is not sufficient to produce the large-scale structure of the Universe. A theoretical calculation shows it takes too much time to form it. Assuming a dark matter with mass of several times larger than one of the visible material, a hypothesis was born that stars and galaxies were formed around dark matter through attracting interstellar gases and stars. The dark matter is indirectly measured its mass and distribution using the gravitational lens effect. When you look at the map showing the large-scale distribution of dark matter in the Universe, you can find the network structure of the dark matter grows with the passage of time (as it approaches the Earth), and it seems to be separated by a huge void. The galaxy formation was demonstrated visually that the galaxies concentrate along the network structure of the dark matter and the galaxies grew in the dark matter.
After inflation, it is reasonable that expansion of outer space has advanced at a constant speed. Recently, it was observed that the far supernova flied away at a speed higher than the speed when considering the expansion rate of the universe is constant. That is, the expansion of the universe is accelerating. Therefore, we are newly introducing and explaining the concept of dark energy. Before 13.8 billion light years, space expands at a speed exceeding the speed of light, so it is called the horizon of the Universe. The current universe calculated from the speed of expansion is a radius of 47 billion light-years. The outermost side of the space is an account which is far away at more than three times the speed of light.
It is thought that force (interaction) was born with the birth of elementary particles. First of all, it was gravity. It is estimated to be 10 exp(-38) seconds after the universe was born. Since other interactions are transmitted by exchange of elementary particles such as photons or gluons, the particle that transmits gravity is called graviton. As gravitational force (universal gravitation) acts all elementary particles, and works to infinity without being interrupted, so it dominates the macro world. Gravitational force is responsible for navigation of the celestial bodies such as the earth, the sun, the galaxy, and it creates a structure of a huge universe.
Space inflation began immediately after the birth of gravity, and was completed at 10 exp (-34) seconds after the universe was born. Then, at 10 exp (-33) seconds, the strong interaction mediated by gluon and the electroweak interaction (weak interaction and electromagnetic force) appeared. Quarks, leptons (6 species. among them, the electron and the neutrino are stable) and the gluons were in a state of free motion in the universe at a very high temperature. The plasma of quark and gluon showed behaviors like gas or liquid. At that time, the weight of a mass like a tip of pin was as heavy as that of the Egyptian pyramid, and the temperature reached one million times of the center core of the sun.
At 10 exp (-13) seconds after the universe was born, along with the cooling of the universe, the electroweak interaction was divided into weak interaction and electromagnetic force. The weak interaction can transmit very short distance, so we cannot observe their impact in the everyday world. Almost at the same time, at 10 exp (-13) seconds thereafter the vacuum was filled with Higgs particles (Higgs' sea, or Higgs field), masses were created in elementary particles (other than photons) interacting with Higgs particles. Quarks and leptons reacted with the Higgs field. When flying in space, they received brakes by the Higgs field, the speed became lower than the speed of light. Also, when accelerating or changing the direction of particle motion, certain external force needs to be exerted.
At 10 exp (-6) seconds after the birth, the quark joined by gluon, protons and neutrons (consisting of three quarks) and mesons (consisting of two quarks) were born. Protons and neutrons formed atomic nuclei via mesons. The elementary particles responsible for strong interactions, gluon, are trapped in protons, neutrons, and nuclei, and from then on, none can see them in the everyday world. As the temperature further declined, protons and neutrons, their associated nuclei, electrons, photons, and neutrinos were left as basic particles in the universe at 10 exp (-4) seconds after the birth. At that time, the universe was filled with dark matter in addition to the elementary particles. The number of nucleons produced was 1 per 1 billion photons.
One minute after the Universe was born, the deuterium atomic nucleus, in which a proton and a neutron are coupled, were stabilized. Then nuclear fusion advanced and light nuclei were synthesized. In the early Universe, almost atomic nuclei were consisted one proton, that is hydrogen (or deuterium, if a large number of neutrons were created) or two protons (helium nuclei).
At first, the ratio of protons and neutrons was 1:1, but the neutrons are so unstable to decompose into protons and electrons. This decomposition sharply decreased after 3 minutes post Big Bang, because the space expanded to reduce the interaction between neutrons and other elementary particles and because the equilibrium was rapidly reached. At this time, the number of protons became seven times the number of neutrons.
Three minutes after the Big Bang, nuclei of hydrogen and helium were formed. There are three kinds of nuclei of hydrogen including one proton and 0, 1, or 2 neutrons. In addition, atomic nuclei of helium are two kinds including 2 protons and 1 or 2 neutrons. The universe was filled with nuclei and free electrons, which was plasma state. Furthermore, very few lithium and beryllium nuclei were born in 1000 seconds after the Big Bang.
When the temperature of universe cooled to about 4000 K (K is absolute temperature) after about 380,000 years after the Big Bang, electrons were captured around the nucleus by electromagnetic force, then atoms were formed. This phenomenon is called neutralization of the universe. Then, the light, which could not go straight by absorbed or released by free electrons, could go unimpeded. Thus the universe became transparent (clarification of the universe). The light filling the universe at this time is observed as 2.7 K of cosmic background radiation today. The size of the universe at that time is estimated to be 1/1000 of the present.
Many first-generation stars appeared to be born 50 million years after the Big Bang. The first generation stars are mostly made of hydrogen, and are larger and hotter than stars that contain heavy elements such as the Sun and emit more photons. In 180 million years after the Big Bang, hydrogen atoms were heated by stellar light, and ionization of the hydrogen atoms began. The first generation stars had a short life span due to its large mass, and supernova explosions frequently occurred.
The story by the simulation is as follows. Small primitive stars of about 1% of the solar mass were formed 300 million years after the Big Bang. The primitive stars gathered the gas around, grew and began to shine strongly when it was about 20 times of the solar mass. Their growth was suppressed by light pressure, and growth stopped at about 40 times the solar mass. Another simulation predicts a huge star that will reach 100 times the solar mass.
Hydrogen left in the space ionized by ultraviolet rays from the stars. This process after about 500 million years from the Big Bang is called re-ionization of the universe. The oldest (furthest) galaxy that can be observed now is a quasar of about 600 million years after the Big Bang (13.2 billion light years ahead). Eventually, as galaxies were formed, the number of hydrogen atoms decreased from outer space, reaching the current concentration level in 940 million years after the Big Bang. This is called the dawn of the Universe.
In the center of a large galaxy in the Universe, there is a black hole with a mass between 1 million and 1 billion times of the solar mass. The black hole at the center of the galaxy is thought to have been formed by the gravitational collapse of a huge gas cloud 1 billion years after the Big Bang. An ancient massive black hole is observed as a quasar. A quasar is a celestial body where powerful electromagnetic waves are generated due to a large amount of substances falling into a huge black hole. Iron was found from the spectroscopic observation of a quasar. Iron is synthesized by nuclear fusion in stars. In the early universe, which is only 2 billion years after the Big Bang, we can find many massive gas bodies with masses that are almost the same as galaxies. Giant gas bodies create numerous stars and would condense into galaxies. Recent observations in the young universe of 4 billion years after the Big Bang suggest that star formation activity was at its peak in large mass galaxies. Stars were born there with an unexpectedly high formation rate.
The lifetime of a star is called evolution. The mass of the first generation stars that were first born in the universe are orders of magnitude larger than those of the present age, because the universe was so small that the high concentrations of hydrogen and helium are available as materials. Hydrogen gas flocculated due to gravity. When the central part of the gas exceeded 10 million degrees, nuclear fusion reaction started.
In the early Universe, the ratio of number of hydrogen with a proton to deuterium containing neutron was estimated to 6:1. Deuterium is generated from two hydrogen nuclei (protons). When two protons collide, one emits positrons and neutrinos and turns into neutrons (Beta plus collapse). Positron annihilates with surrounding electrons and turns into thermal energy. Thus, a deuterium nucleus is formed composed of a proton and a neutron.
When a proton, a hydrogen nucleus, is bonded to a deuterium nucleus, a helium 3 nucleus (two protons and one neutron) is formed. Two helium 3 nuclei react with each other to form a helium 4 nucleus (two protons and two neutrons) and two hydrogen nuclei (one proton each).
The helium nucleus accumulated in the core of the first star as an ash of the nuclear fusion reaction, and outside the core, the hydrogen nucleus continued fusion reaction. Eventually, as hydrogen nuclei become less and nuclear fusion reaction becomes weaker, the temperature dropped.
As the temperature decreased, the central core shrank due to gravity, and its temperature and pressure rose. Then helium nucleus began nuclear fusion reaction. Three helium nuclei turned into one carbon nucleus (6 protons). Furthermore, oxygen nucleus (protons 8) was formed from a carbon nucleus and a helium nucleus. Subsequently, carbon underwent a nuclear fusion reaction.
Nuclei such as neon (10 protons), sodium (11 protons), magnesium (12 protons), etc. were formed from 2 carbon nuclei. Further nuclear fusion reactions produced silicon (14 protons), Iron (26 protons), and so on.
When the main nuclear fusion reaction ends inside the star, heat was no longer generated, the core of the star shrinks. Then the temperature and pressure of the core rise to start the next nuclear fusion reaction of heavier nuclei. The temperature and pressure of inside of the star gradually become high. As heavier nucleus accumulates in the core, the core of the old star has several layers of nuclei. In the core of large and old star, iron nuclei were accumulated.
As the atomic number increases, nuclear fusion reactions are less likely to occur because the Coulomb repulsion between the nuclei (the force that particles with the same charge repel each other, the nucleus has the positive charge of the proton) becomes large. The heaviest element that can be generated in the nuclear fusion reaction is iron, having an atomic number of 26. That is, nuclei lighter than iron were produced inside the first generation stars.
After the universe was born, in the hundreds of millions of years, the first generation stars got a supernova explosion and became black holes. The energy of the supernova explosion released relatively light nuclei produced by nuclear fusion reaction into outer space. In addition, heat and pressure of explosion created a heavier nucleus than iron.
The gas temperature dropped when the first-generation star exploded and the heavy nuclei were scattered into the space. The relatively cold gas clouds were broken apart and each became a star. After that, there was no huge star like the first generation star. Black holes are formed by gravity collapse when a relatively large star explodes as supernova. The mass is at most 10 times the solar mass.
When the iron core of the first-generation massive star reached 5 to 10 billion K, the energy of the emitted light reaches the level of energy connecting neutrons and protons in a nucleus. This high energy light caused nuclear fission. The iron nucleus decomposes into helium nuclei and neutrons, which is an endothermic reaction. As the temperature decreases, the pressure maintaining the core mass sharply drops and the outer layer of the star fall toward the center. The nuclear fusion reaction accelerates at once, the outer layer of the star blows off, and a supernova explosion occurs.
In the case of large-mass stars, under extremely high pressure, an electron is absorbed by a proton and becomes neutron, so the staller core becomes to contain only neutrons. This is called a neutron star. If the mass is larger, the extremely high gravity presses a neutron, and the core falls inside due to strong gravity. This is called gravitational collapse, and the core condenses into a black hole.
In supernova explosion, a large amount of neutrons are generated. Neutron has no charge, Coulomb repulsive force does not work so that they collide and are easily absorbed with the surrounding nuclei. A nucleus containing more neutrons than usual becomes unstable, so excess neutron releases electron and gamma ray to become a proton, hence increases the atomic number by one. With this repetition, a large amount of heavy nuclei more than iron were created in a short time.
The first generation supernova explosion blast (gravity wave) blows out the surrounding gas, compresses the interstellar gas and creates a number of second generation stars. Stars of the second generation have a long lifetime because the mass is small compared to the first generation. The second generation stars are currently observed in clusters around the galaxy as a star with poor metal element. When a massive star among the second generation reached the end of a supernova explosion, a large amount of heavy nuclei were supplied to the universe. The stellar made after this contains a relatively large amount of metallic elements and is called a third generation star. The sun is the third generation. It has been confirmed in galaxies 10 billion years ago that their interstellar gas contain very low heavy elements. In the galaxies of the same age, it is also observed small number of galaxies storing large amounts of dust and heavy elements.
Even trace amounts of heavy elements have a great influence on the formation and structure of stars. Heavy elements emit more infrared rays than hydrogen and helium. When heavy elements are included, even a smaller amount of gas can be contracted into the stars. Heavy element acts as a coolant when stars are formed and suppresses expansion due to heat. On the other hand, if only hydrogen and helium are component, the temperature of the gas rises during the formation, and only very massive cloud can become a star. First generation stars are considered to be 100-1000 times the mass of the sun. From the second generation onwards, stars of relatively smaller weight have come to be born.
In the process of making a star from a gas cloud of about 100 times the mass of the sun, when the mass of the center star reaches 20 times the solar mass, the pressure of light prevents the sedimentation of the gas to increase the weight of the star no more. However, in reality there are gigantic stars. When the light pressure and the gas settling press together, Rayleigh-Taylor instability occurs with a slight fluctuation, and the gas settlings fall into a star as a mass. According to the simulation, from a gas cloud about 100 times the mass of the sun, two stars of 30 times and 40 times the solar mass were born. In the universe there are many binary stars because there were many gas clouds of large mass.
The first galaxy was formed 300 million years after the Big Bang. The Milky Way Galaxy, to which the solar system belongs, began to form one billion years later from the Big Bang. The density fluctuation of the dark matter at a level of about one over hundred thousandth that existed in the early universe grew under its influence of gravity and gathered baryons, forming celestial bodies of various sizes everywhere. A galaxy with many stars and interstellar matter was born in the space where massive substances were gathered. The dark matter surrounding the galaxy is spherical. Galaxies formed in the dark matter turned into a disk shape by rotation.
In the universe up to two billions years after birth, glowing lumps of hydrogen gas of galaxy size are observed and they are called Lyman-alpha blobs (LABs). Having a black hole in the center, it looks shiny by the substance falling into the black hole. The size of LABs is the size of the current galaxy. It is thought that LABs evolved into galaxies. Unless LABs are assumed for the evolution of the universe, the size of the modern galaxy will be enormous in size. It is thought that the formation of the second generation star in LABs was completed by from 3 to 4 billion years after the universe was born.
The star formation rate of the galaxy is correlated to the total mass of the material which makes the star. From the beginning of the universe to the present, the star formation rate has gradually decreased. Even in early galaxies of the universe, the star formation rate increased with the mass of the galaxy, and its efficiency was more than 20 times higher than it is now. The black hole located in the center of the galaxy is called blazar. Study examining the gamma-ray attenuation from blazars in the range of 200 million light years to 11.6 billion light years shows that the gamma ray was the weakest between 9.7 and 10.7 billion light years, indicating that many stars were born in the area. That amount is 10 times of the current. In other words, after the Big Bang, there was a peak of star birth 3 to 4 billion years later.
The giant black hole at the center of the galaxy is thought to have been born by gravitational collapse of the massive gas cloud directly in the early universe. A medium-sized black hole was found at the center of a small galaxy. In addition, the mass of the black hole at the center of the galaxy, including medium-sized black holes, correlates with the size of the galaxy. Therefore, scenarios are predictable where black holes grow by merging with galaxies and absorbing surrounding stars. The Dark matter apparently influence to this process.
The galaxy group to which the Milky Way galaxy belongs, to which the solar system belongs, is called the Local Group of Galaxy . In the Local Group of Galaxy, the largest galaxy is the Andromeda galaxy, and the heaviest galaxy is the Milky Way galaxy. There are many companion galaxies are bound by their gravity around both galaxies. One of the groups of galaxies that are closest to the Local Group of Galaxy is the Sculpture Room Group of Galaxy and the Maffei Group of Galaxy, which are separated by 7-10 million light-years. In addition, the Ursa Major M81 Group of galaxy, M101 Group of Galaxy, Aquarius M51 Group of Galaxy, Centaur A / M83 Group of Galaxy. There is a Virgo galaxy cluster about 50 million-70 million light years away, all of which are included in the Virgo super galaxy cluster.
Although some astronomers think that the Local Group of Galaxy is being taken into Virgo Galaxy Group, there is a negative opinion because the expansion of the universe is accelerated by the dark energy. Assuming the maximum estimate of total mass of the dark matter, it cannot fill up the gap speed difference between speed of the clustering of galaxies and one of the expansion of the universe. Therefore, according to the expansion of the universe, the space between each cluster of galaxies and super galaxies increases. Ultimately, it is predicted that individual clusters of galaxies are blocked by the wall of light velocity (separation speed exceeds light speed) and separated as an isolated universe (space).
The establishment of the Great Unified Theory will give a conclusion as to the universe in the distant future, whether isolated small universe by a cluster of galaxies will be, Big Crunch will be or expansion forever will come, through analysis by the theory.
The Milky Way Galaxy is a group of celestrial bodies to which our solar system belongs, where are globular clusters, open clusters and other stellar groups, and interstellar matter. Most of the stars are in the disk part, and the star in the center bulge part is older than the star in the spiral arm part.
The Milky Way Galaxy was born by gathering stars around a super massive black hole in the dark matter clouds. The coalescence of the galaxy was at its peak in the 3 billion years after the Big Bang. This is the time that many stars were born in the Universe. Some small galaxies were moving around the young Milky Way Galaxy. They are named as Enceladus or sausage. From 3 to 6 billions of years after the Big Bang, Milky Way galaxy swallowed small galaxies. As a result, the disk of the Milky Way galaxy was spread over and form spiral pattern.
Milky Way Galaxy absorbed small galaxies and in each time many stars were produced actively. When the ages of the stars in the Milky Way galaxy were tallied, three times in the past were observed when a large number of stars were made. The growth of the Milky Way Galaxy stopped as the universe expanded and the small galaxies nearby were exhausted. The relic of the galaxy from which the star was stripped is caught around the galaxy as a globular cluster. Examining the nature of the globular clusters may partly uncover the history of the formation of the Milky Way galaxy.
A recent example of a galaxy collision occurred about 2.5 billion years ago, with the passing of the Triangulum Galaxy and the Andromeda Galaxy. The two galaxies passed each other within only 40,000 parsecs (130 thousand light years). The strong gravity of the Andromeda Galaxy exerted a strong tidal power to the Triangulum Galaxy, and millions of stars were thrown out of the Triangulum Galaxy.
At the center of the Milky Way Galaxy, there is a strong radio source, a huge black hole called "Sagittarius A". Since the interstellar matter is concentrated at high density around it, it cannot be seen optically. Observations were made to track the movement of the star existing near the center of the Milky Way Galaxy from the 1990s for more than 10 years. Analysis of the trajectories by the universal law of gravitation revealed that the mass of the giant black hole at the center of the Milky Way Galaxy is 3.7 million times that of the sun. The diameter is 0.15 astronomical units (22.5 million km).
There is a region called a halo that spherically surrounds the Milky Way galaxy outside the disk part. The oldest celestial bodies among the stars forming the Milky Way galaxy are globular clusters scattered in this area. These stars are second-generation stars that contain heavy elements such as iron only about a few hundredths of the sun. The 11.7 magnitude star of the Cetus has only one-eighth of the sun's abundance ratio, but it was unusual to detect thorium 232 and uranium 238 of radioactive atoms. Based on their relative abundance ratios etc., its age was determined to be 12.5 billion ± 3.3 billion years. This value is considered to correspond to the age of the Milky Way Galaxy.
The disks are occupied by dark nebulae and stars belonging to population I (third generation) such as main-sequence stars and cepheus type variable stars. The red dwarfs are expected to be the most abundant stars to form the galaxies. Their size is less than 1/3 of the diameter of the Sun, the surface temperature is a dark star of about 3500 degrees. The fusion rate of hydrogen is slow, and the lifetime is very long. There is nothing visible to the naked eye. 348 celestial bodies within 10 parsecs (33 light years) from the Sun were examined, of which 239 (about 69 percent) were red dwarfs. Also, half of the stars are binary stars.
The spiral pattern of the galaxy is a compressional wave of stars. It happens that gravitational pockets are formed in high density places and it takes time for stars to pass there. In other words, because the stars were rotating motion and accumulated, they became an arm structure. In addition, the interstellar gas also gathered and became a place where stars can be born.
Supernova explosion promotes the birth of stars. When a massive star is formed in the middle of a gigantic molecular cloud, the light presses the molecular clouds to form high density region or ionizes the surrounding molecular clouds. Molecular clouds are condensed into stars so that the light reaches even farther. With this iteration, a characteristic stellar group structure (OB association) was formed.
Materials that do not emit light by themselves other than stars are classified into scattered nebulae, planetary nebulae, dark nebulae, etc. depending on how they appear. They are mainly gas and dust. So called interstellar gas is that it has a density of 100 times or more against ordinary outer space. It will be compressed by its own gravity and nuclear fusion will begin and stars will be born.
The solar system lies in the plane of the Milky Way Galaxy and is on the galaxy center side of the Orion arm, which is sandwiched between the sagittarius arm and the Perseus arm. It locates 26 thousands light years from the center of the galaxy. The sun would have been born at the same time together with about 50 Sun-type stars within the area of a radius of 30 light-years. The age of the sun is calculated to be 4.6 billion years from the measurement of the collapse of uranium 238. That is, 9.1 billion years after the universe was born, 7.9 billion years after the Milky Way Galaxy was born. The sun goes round the center of the Milky Way Galaxy once in 200 million years. It is estimated 23 laps already.
The elements existing in the solar system are, in increasing order, hydrogen, helium, oxygen, carbon, nitrogen, iron, magnesium, sulfur, aluminum, sodium, calcium, nickel. Most of the substance (mass) is in the Sun. These elements are the nuclei formed by the nuclear fusion reaction inside the stars. Many kinds of heavy atoms produced by supernova explosion were also included.
Clouds of interstellar matter that became the solar system was gradually condensed and falling into the center of gravity. Most of the gas was such as hydrogen molecules and carbon monoxide molecules. Although the ratio to the total mass was small, there was also a large amount of minute solid particles of about several micrometers. The gas swirled because the angular momentum was preserved while falling and condensing. When agglomerating due to gravity, gravity and centrifugal force antagonize in a plane perpendicular to the rotation axis of the disc, and the material does not immediately fall to the center. On the other hand, since the centrifugal force does not act in the direction parallel to the rotation axis of the disc, aggregation by gravity proceeds. As a result, the material distribution gradually flattened and a rotating accretion disc was formed.
Then a giant gas ball was made at the center of the rotating accretion disc. The core of the gas ball was compressed and its temperature rose. When its temperature exceeds the critical, nuclear fusion of the hydrogen nucleus started and became the primitive Sun.
The dust materials in the accretion disc gathered slowly, making small lumps due to adhesion and inelastic collisions. The small lumps are called pebbles. These pebbles became a planetesimal with a diameter of roughly 10 km. The planetesimals grew while revolving around the sun, striking each other, stuck together, being broken by the impact of the collision. Some planetesimals seemed to have a core of metallic iron.
Only some planetesimals grew selectively and became protoplanets. They grew and grew by collecting a lot of small planetesimals remaining in the surroundings. When the activity of the Sun rose, solar wind was generated. The wind blew the gas out of the area close to the Sun. At last, the protoplanets collected all surrounding planetesimals. The planets ceased to grow and were born with hard ground like the earth.
When the mass of the protoplanet exceeds about 10 times the mass of the earth, the planet can effectively collect hydrogen gas by gravity. In the protoplanetary disk, because of the mass of gas component was as many as 100 times that of the solid component, the mass of such a big planet rapidly increased. Jupiter type planets which had a mass of 10 times of the earth mass were formed, wearing gas of many times the mass of the core around the nucleus (core).
Jupiter was short of weight to switch on nuclear fusion. Similar gaseous gigantic planets were born outer than Jupiter, named Saturn, Uranus, and Neptune. Metallic elements are fewer at the outer side of the solar system, and are considered to be composed of light elements such as ice and dirt.
The planetesimals between Mars and Jupiter, which could not grow into a large planet, stayed as many asteroids and became the asteroid belt. Also, on the outside of Neptune there are many celestial bodies without gas, called Edgeworth/Kuiper belt. The origin of a short cycle comet is here with a cycle of 200 years or less. These objects are collectively referred to as dwarf planets. Pluto became to be regarded as a dwarf planet. On the outside of the solar system, the planet formation like the early solar system still proceeds slowly. As the primitive molecular clouds evaporated, these objects appear to have been left behind on planet formation.
By examining the age of the meteorite, it is calculated that the solar system was born 4.6 billion years ago. In the primordial solar system, it is estimated to be 10 to 100 million years from the time when molecular clouds begin to shrink to the time when the solar system is formed. From the accretion disc to the formation of a planetesimals with a diameter of about 10 km was quite quick, estimated to be around 100,000 years. The planetesimals were assembled over the 30-40 million years to form the earth.
The sun releases supersonic plasma called solar wind in every direction, and it creates a huge spheroid cavity in the interstellar gas. This cavity is called the heliosphere and spreads over about 100 to 150 astronomical units (AU) (1 AU is the average distance from the earth to the sun, about 150 million km). The supersonic solar wind decreases rapidly at the surface of termination shock, and then equilibrated at the surface called the heliopause. Outside the terminal shock wave surface, the solar wind flows at low speed and is called Helio Sheath. In this area, the interaction between the solar plasma and the interstellar gas becomes dominant.
In the 2000s, growing star systems were discovered one after another by observations with the ALMA radio telescope. Various primitive stellar disks were discovered. It was found that the beautiful planetary system like the solar system is exceptional and there are various planetary orders.
The earth that had orbited around 150 million kilometers from the primitive sun has a different appearance from other planets.
Constituents of the primitive Earth are estimated by investigating planetesimals that are not absorbed by the planet, drifting in the current solar system. Specifically, they are a meteorite and a comet. Among the meteorites, the oldest one is carbonaceous chondrites that existed since the planet was formed. The chemical composition of this meteorite is the same as that of the solar system except for hydrogen and helium. Besides iron and nickel, it contains a considerable amount of water and hydrocarbons. It includes small spherical particles called chondrule, which is said to have formed 4.56 billion years ago. In the state of zero gravity, volatile molecules will assemble to become spheres. Carbonaceous chondrites are thought to be meteorites that are not subjected to thermal transformation such as melting and solidification.
The rocks in the Kuiper belt are disturbed by the gravitational force of Neptune etc, and they become a comet. By the same mechanism, rocks and celestial bodies are also injected from the Kuiper belt to the asteroid belt which located inside of Jupiter's orbit. The celestial body from the Kuiper belt is heated as approaching the sun and loses its volatile components and it can become a normal rocky meteorite. The rocks are still continuing to fall to the Sun now.
In the current solar system, the long tail of a comet will additionally contain water vapor around the earth's orbit. However, at that time when the earth was born, the energy radiation from the sun was less than present. The temperature around the Earth's orbit is much lower, and the planet may have contained a lot of ice and organic matter of low molecular weight. The surface of the ancient Earth may have been a mud containing a large amount of simple carbon compounds rather than rocks.
The planetesimals falling to the earth melt due to collision energy, and water and gaseous components contained in them evaporated rapidly. When the earth became about half the size of the present, gravity reached a strength not to let gas escape, and a layer of the atmosphere was formed. Furthermore, volatile substances were supplied to the Earth from the meteorites fallen to the Earth. The atmosphere and the sea were born 4.37 billion to 4.2 billion years ago. The greenhouse effect of the primitive atmosphere slowed the rate at which heat escapes to outer space, the surface of the Earth gradually turned into magma. Eventually, the surface changed to a boiling magma ocean, its depth reached 500 km, and its temperature reached over 1,000 degrees Celsius. In the magma ocean, heavy iron and other heavy components separated from light rocks and accumulated at the bottom of the magma ocean. However, there are negative opinions on the existence of the Earth's atmosphere before the giant impact.
When the Earth reached to a size with radius of about 70% of the current, the heavy metal accumulated at the bottom of the magma ocean fell to the center at once and made a nucleus. At this time the gravity energy released to melt the Earth completely, then light rock component, which is the equivalent with magma ocean, were separated from the metal nucleus.
If most of the heavy metals such as iron sink as nuclei, the elements left on the surface of the Earth were oxygen, carbon, nitrogen, silica, magnesium, sulfur, aluminum, sodium, calcium etc. Carbon, oxygen, and nitrogen provide a framework for making organic matter that constitutes organisms. These elements make volatile molecules. The meteorites were heated while passing through the primitive atmosphere and the volatile components such as carbon dioxide, water and nitrogen would have released to the primitive atmosphere.
Both comets and asteroids were possible as small objects that supplied water to the ancient Earth. In the past, the comet theory that the comet played a central role was the mainstream. Comets have a main component of ice with dusts around the icy core. On Halley's comet, 80% is ice. However, when the Rosetta space probe surveyed the components of the Gerasimenco comet in 2014, it was found that the hydrogen isotope ratio was significantly different from that of the Earth's sea. At present, the asteroid theory is dominant.
The early Earth was cooling rapidly, so different material layers were kinetically confined locally. Especially the hot interiors were separated from the surface. This means the Earth is far away from thermal equilibrium. The Earth constantly radiated heat towards the Universe and lost some materials. The surface of the Earth constantly obtains energy from an external light source called the Sun, and the surface of the Earth's crust and atmosphere is affected by it.
At the final stage of the formation of the Earth, a planet (called Theia) collided with the Earth, which has about 10-15% of the mass of the Earth (similar size as the Mars). As a result, the last 10% mass was added to the Earth, but the surface layer of the Theia and the Earth splashed around the Earth (Giant Impact). The materials which revolved around the Earth gathered again to form the Moon as an independent celestial body. It is 4.53 billion years ago deduced from the age of the moon rock. The birth of the moon will be around 90 million years since the birth of the solar system. This period is longer, because other celestial bodies of the same size as the Moon presumed to be formed in hundreds of thousands of years.
According to a simulation, when a collision occurs on the primordial Earth in the state of magma ocean, the magma blows out as a jet, which becomes a disk in the Earth's orbit and eventually becomes the moon. At this time, after the collision, the material of Theia and the material of the magma ocean scatter around the earth. The Theia's material immediately collides with the Earth again. On the other hand, the Earth's magma ocean component remained in orbit, so the moon contained 70% of the Earth-derived component. It can be explained that the isotopic ratio is the same between the moon and the Earth's crust.
Thea's iron core melted and covered other earth with clouds like a cloud. The metal storm took oxygen atoms from water molecules and metal oxides sunk into magma ocean. The remaining hydrogen covered the Earth as a thick atmosphere for about 200 million years. On the Earth immediately after the magma ocean solidified, rocks covered the surface of the Earth, and carbon dioxide, nitrogen and sulfur dioxide erupted from the Earth. When a hydrogen blanket was applied in this state, organic compounds a low molecular weight were synthesized. 4.46 billion years ago, the Earth was cold enough to have the Sea, and it was estimated that RNA was produced 4.35 billion years ago.
If the Giant Impact did not occur, the precious metal should be only in the core after magma ocean cooled and hardened. It is the Giant Impact that explained the fact that precious metal is on the surface.
At the time of formation by Giant Impact, the Moon was in the vicinity of the Roche limit (the distance inside where the satellite was destroyed by the tidal force, about 50,000 km). At that time, the Earth rotated about 6 hours, the moon had one lap in 10 hours. Friction due to the tidal force was produced by the deviation between the moon's revolution and the Earth's rotation cycle. As a result, the rotation of the earth decelerated, the moon was accelerated and moved away.
Tidal force converts the energy in gravity potential into heat. It is an important mechanism that fundamentally dominates the evolution of the planetary-satellite system, such as heating the entire satellite, changing the internal structure, changing the orbital motion by generating a gravitational torque. At present, phenomena are observed that tidal energy dominates between Jupiter and Saturn and satellites, that is, activity of Jupiter's Io and ice ejection activity of Saturn's Enceladus.
After the ocean was formed on the Earth, the great tidal power produced a height difference on the Sea, and it is thought that the height of the wave had reached 1000 m. Supposing that the estimated ancient ocean depth would be 2000 m, a huge and intense wave had been washing the surface of the earth continuously. Also, the solid part of the Earth was deformed, then the equatorial diameter was flattened nearly twice the polar direction. On the Archean Earth, arcuate islands formed by plate tectonics were washed away by tidal waves and craters made by gigantic meteors were also buried and flattened. Since the magnitude of the tidal force is inversely proportional to the cube of the distance from the earth to the moon, the effect of tidal friction is drastically weakened, and the earth surface is thought to be stable in hundreds of millions of years.
In the Precambrian epoch 900 million years ago from now, it is estimated that one day of the earth is 18 hours. At this time, the year of the earth is about 480 days, and the distance to the moon is about 350,000 km. In the past several hundred million years, the rate of the deceleration of speed of the Earth's rotation (= the speed that the moon goes away) is also nearly constant. The change in the distance from the earth to the moon is measured to be 3.8 cm each year in present, using the mirror placed on the moon by the Apollo project.
Due to the giant impact, the Earth melts again to the core, and the surface was considered to be solidified at 4.53 billion years ago. Thear's metal core coalesced with the Earth's core or became the core of the moon. After the giant impact, the atmosphere was relatively small until about 4.1 billion years ago. Since the Earth located inside of the snow line in the solar system at that time, the volatile components were blown off as gas outwards to the solar system by the solar wind.
As carbon dioxide was absorbed into the sea and the atmospheric pressure dropped. Plate tectonics started. Plate tectonics transported heavy metals from seawater to the mantle. 4.2 billion years ago, a liquid outer core was created, and a magnetic field was created by convection in the core.
Fine particles of diamond made 4.2 billion years ago were found in zircons formed at 3 billion years ago in Australia. Diamonds are not formed in magma ocean. Since zircon can be made by volcanic activity, the diamond made 4.2 billion years ago at the bottom of the crust should have moved to near the ground surface over a billion years. Diamond made 4.2 billion years ago means that the crust had already existed at that time, the ocean and the atmosphere should have existed as well. The oldest continental crust is estimated to be about 4.25 billion years ago.
The pillow lava is one of evidences of the presence of the Sea. It has a characteristic form because lava was blown into water and cooled rapidly. Oldest pillow lava was found of 3.8 billion years ago in Isua, Greenland. A metamorphic rock made from granite of 4 billion year old was discovered in the Acasta area in the northern Canada. Granite shows the presence of plate tectonics and the sea.
At first, water turned to rain at high in the sky where the atmospheric pressure and temperature were low, but evaporated before it reached the surface of the earth. As the atmosphere cooled down, the rain gradually began to reach a low position. Steam becomes liquid water when it becomes at 100 atmospheric pressures and 650 K (380 C) or less in absolute temperature. This temperature is called the critical temperature of water. When the primordial atmosphere was 100 atmospheric pressures (mostly considered carbon dioxide), the first rain fell to the ground when the surface cooled to around 300 C. It was a decisive incident that the earth had a different dress from other planets. It took about 45 million years from formation of the Earth.
Rain efficiently cooled the surface of the Earth. Basaltic rocks were made on the ground to form the crust. Hydrogen chloride was dissolved in the rain, so it was strongly acidic. Rain water containing hydrochloric acid dissolved ions such as magnesium, calcium, aluminum, sodium, potassium, iron from rocks on the ground and was gradually neutralized.
When the hydrochloric acid was neutralized, a large amount of carbon dioxide in the atmosphere dissolved in the primitive ocean, bonded with calcium ions and precipitated as calcium carbonate (limestone). Carbon dioxide contained in the primordial atmosphere fell to about 10 atmospheric pressures and the greenhouse effect of the atmosphere by carbon dioxide was relieved. The primordial atmosphere at that time consisted of 90% carbon dioxide and nitrogen.
The Archean atmosphere contained high concentrations of carbon dioxide, and also in seawater or hydrothermal plume, carbon dioxide and carbonate ion concentrations were high. The hydrothermal alteration of the oceanic crust made carbonate minerals crystallize, then the silicate concentration increased in the hydrothermal ejection, calcium ions in the seawater decreased, and the concentration of the phosphoric acid increased.
The sedimentary rock on the surface of the Earth contains carbon which corresponds to as high as 90 atmospheric pressures in terms of carbon dioxide. This pressure is almost the same as Venus' atmosphere. The atmosphere of Venus consists of rich carbon dioxide and nitrogen. At the top of the atmosphere of the same depth of the Earth's one, the temperature is lower than the Earth. Below that there is a dense and high-temperature atmosphere of 50 km. As the altitude lowers and the pressure increases, it gets hotter. It reaches 400 C at the bottom. The frequency of occurrence of lightning seems to be quite high, but it seems to be different from the lightning strike of the Earth which is generated from the cloud (a group of water drops).
Observation of the moon craters estimates that most of the craters were made intensively about 4.1 billion years ago by impacts of asteroids in the orbit between Mars and Jupiter deduced from the size distribution. A mechanism of this phenomenon was studied by simulation. It was approximately 4.1 billion years ago that Uranus and Neptune were formed. The formation of these two planets is thought to have displaced the orbits of Jupiter and Saturn, then the orbit of the asteroids was also influenced. The orbital change of the giant planets disturbed the orbit of asteroids, then many asteroids flutter in the solar system. Approximately 4.1 billion years ago from now, asteroids have fallen as meteors to the Earth during from tens to hundreds of millions of years and is called the late heavy bombardment. Since they were meteorites from the outside of the snow line, a large amount of water and carbon compounds were supplied to the Earth at this time. The depth of the sea of the primitive Earth is estimated to be approximately 2000 meters. The surface of the Earth was almost covered with the ocean. There was a basaltic crust below the sea and a thick atmosphere above the sea.
The number of meteorites that fell to the Earth during the late heavy bombardment period is estimated to be 22,000. Craters with size of 2000 km were estimated to 40, and those of 5000 km were expected to be several. These gigantic meteorites had several hundred kilometers in diameter, completely dried up the sea, broke through the crust and disturbed the upper part of the mantle. The rock temporarily melts, the substance in the mantle was pumped up to the surface, and the substance on the crust was embedded in the mantle. The collision of the meteorite caused the sea and lava to splash into the atmosphere, producing a large amount of aerosol, and mixed with the atmosphere. The sea recovered safely even after the gigantic meteorite collision. Lava was cooled by the sea, and brought various substances to the sea. The basaltic crust revived by the suddenly cooled lava.
When a celestial object collides with the crust, a large amount of crash debris called ejector is generated. Among the ejectors, particularly fine ones are susceptible to chemical weathering reaction because of their large surface area. A large amount of ejector was generated by frequent collision of the heavenly bodies, as a result, carbon dioxide (carbonate ion) dissolved in the sea precipitated as carbonate. Therefore, carbon dioxide in the atmosphere gradually declined.
At that time, the Sun emitted only about 70% of the current energy. With this amount of radiation, the Earth froze all over. The frozen Earth melts rapidly due to the fall of the meteorite, and sometimes the sea may have repeatedly evaporated completely. If the amount of carbon dioxide is large, there is a possibility that the Earth did not freeze due to its greenhouse effect.
Impact experiments on small meteorites have shown that meteorites become powdered at the surface of the sea. At that time, organic matter may have been free from decomposition by impact heat. In addition, the fine meteorites may have reached the terminal velocity with the atmosphere as a cushion, and was continuously deposited in the sea. If a large amount of fine meteorites remained after the formation of the earth, it is possible that the organic matter was supplied on the Earth.
By my personal view, it is probable that when the meteorite fell and the sea and the rock evaporated, the carbon compound was carbonized by heat and highly reactive metal carbide was formed. It seems that metal carbide molecules bonded to each other to modify them and developed into polymer compounds. The collision of the meteorite may have supplied new substances, complex organic matters and compounds.
The oldest rock existing is 4 billion years ago (exactly 4,030 million years ago). Rocks made after 3.8 billion years ago can be found in many places. Sedimentary rocks are also found. From these results, it seems that rocks have been preserved stably since 3.8 billion years ago. The sea seems to have stabilized since 3.8 billion years ago after the end of the late heavy bombardment period.
Among the rock formed by the Earth's plate tectonics system, the oldest one discovered so far is 3.8 billion years ago. A series of rocks formed along with the division of the ocean floor was discovered in Greenland by an International Research Team. Therefore, the system of plate tectonics seems to have started relatively early in ancient Earth. This rock is called an ophiolite, a characteristic layer structure which an oceanic crust is exposed to the ground. It is of thickness about 10 km which is equal to the thickness of the oceanic crust, including various kinds of volcanic rocks.
The mantle convection in Archeozoic era was divided into two layers. The crust was swept by the mantle convection and became a plate. The mantle convection in the upper mantle layer was about 670 km thick and was a nearly circular convection. The crust is expected to be divided into plates of about 700 km in diameter, which is about the same size as the mantle convection. We can estimate about 200 plates are there on the surface of the Earth at that time. If the plate moved of a speed of 3 cm per year, whole plate will enter the mantle in about 20 million years. The speed at which the current plate sinks is approximately 0.5 cubic kilometers each year.
The plates moved on the mantle convection. At the place where two plates collide, one plate will be on top and the other will sink into the mantle. It is called a subduction zone, and the arcuate islands grew. The plates are generated where the mantle gets up. It is called the ridge. In Archeozoic era, the total extension of the arcuate islands and the ridge on the Earth would have been nearly 20 times those of the modern era.
In the ridge, cracks were formed in the bottom of the ocean by the mantle which springs up, magma was supplied from the rising mantle, and a basaltic crust was formed. In the ridge, hot water blew out of the sea floor due to the heat brought from the mantle, and a large amount of reducing gas such as hydrogen sulfide, methane, hydrogen and metal sulfide such as iron and manganese was supplied to the sea. The depth of the sea of the primitive Earth is estimated to be approximately 2000 m.
In the subduction zone, the trench was formed. Since the subducted plate contains water, it melts at a relatively low temperature in the mantle. It supplies magma which squirts to the sea, making a submarine volcano including a large amount of granite. Eventually, an orogenic belt is created along the plate boundary, and the islands develop. Probably the island would have been arcuate. Volcanic activity released reducing gases such as hydrogen sulfide, methane, hydrogen from the ground into the ocean and the atmosphere. The sinking plate left numerous adornments on the arcuate islands. Even if there was a precipitate of organic matter at the bottom of the sea, they were rarely buried deep in the ground.
The land that existed on the primitive Earth is expected to be only the island. Orogenic movement occurred in a large scale where the plate collides, but no evidence is left. Lands affects flows in the ocean and the atmosphere. If the land is small, the clouds will not be like the present complicated pattern, but they will have been regularly lined up like striped patterns seen on Jupiter and Saturn, due to the influence of rotation. It seems that flows of the ocean were regularly arranged in the same way and were layered. Sedimentary rocks, if made, are in a small amount. Up to 2.8 billion years ago, the continent is only about 20% of the current lands.
Looking at the completeness of living organism in present, I am surprised that hundreds of proteins are involved in one living phenomenon. Common cellular activities include gene replication, gene transcription, translation of mRNA, synthesis of proteins, transport of secreted proteins, processing of proteins, synthesis and degradation of lipids and amino acids, photosynthesis, glycolysis, TCA circuits, ATP synthesis driven by membrane potential, protein degradation, intracellular degradation of organella, secretion of molecules and so on. Furthermore, replication of these molecular devices is attained.
Protein is a very complex molecule and functions as a nano-machine. Many kinds of proteins are gathered to create huge structures and work together in series. Nucleic acid responsible for genetic information cannot act on its own and always needs assistance by proteins. In the system from gene to protein synthesis, nucleic acids and proteins cooperate together.
The membrane structure is not merely a shield against the outside world. The protein embedded in the membrane creates a non-equilibrium state on both sides of the membrane to produce energy (ATP) and also sends nerve pulses. Membrane protein also takes extracellular nutrients and catches information molecules. Eukaryotic cells have many folded membrane structures in the cell and carry out a special reaction in the isolated space.
In fact, in order to elucidate the process of the creation of life, it is necessary to clarify how these functional units were born from inorganic molecules, but also how each functional unit interacts to create an organic relationship among them. Even if these parts are prepared and are mixed, living system cannot be born. Was it inevitable that life was born? Or have many incidents stacked in very long time? It is still unknown, and even putative clues for elucidating it are suspicious.
The essence of life is information. That is, the information that constructs the molecule functionally as an organism is the essence of life. The key to elucidating the birth of life is the birth of information necessary for life, the material basis of information, and the mechanism by which information is replicated to the next generation. Currently, the first genetic information molecule is considered to be RNA. However, we must consider how information on the amino acid sequence of the protein has been written to the RNA molecule.
For the birth of life and its early evolution in several following chapters, I am assembling fragmentary scientific reports into an inevitable story to make a hypothesis on the origin of life.
In order to organize the researches on the origin of life and to align them along the time, I consider how molecular and molecular devices that make up the living body were created from a simple one to a complicated one. The following items are scheduled as follows. Up to "the mechanism of heredity" is the construction of parts, after that it corresponds to the assembly of parts.
But maybe the opposite way of thinking can be possible. It is possible that massive carbon clusters (substances such as graphite or fullerene) were geologically born from carbonate rocks (limestone, etc.) in a reductive environment. Or the possibility that the mountain of carbon decomposes slowly in the seawater to generate macromolecules. As I will repeat in the following chapters, the sufficient density of the molecules involved in life activities is not considered to have been produced naturally. I think that a strong concentration process is necessary. The story that cells are made by simply assembling molecules is contrary to the second law of thermodynamics. Considering that a carbon polymer of mountain size of high energy state was born on the primitive earth, problems of concentration and molecular aggregation could be solved.
How long has it been until the birth of life? The Hades era was till the late period of heavy bombing is over at 3.8 billion years ago. After that, until 3.8 to 2.5 billion years ago is called the Archean era. The fossil was found of the first cell (with a membrane structure) about 3.5 billion years ago.
When the sea was appeared, the Earth is covered with thick clouds. At that time, water vapor, carbon dioxide, and nitrogen were turned into reactive radicals by ultraviolet rays from the Sun, particle beams from the space and lightning discharges in the sky. Then chemical reaction among these molecules and the radicals made simple organic compounds, such as hydrogen cyanide, cyanoacetylene, formaldehyde. Organic substances were sometimes supplied from meteorites and meteors. These molecules melted into raindrops and dropped to the sea. There were very small lands in those days. Most of the highly reactive material molecules reacted with water, but sometimes they mutually reacted to form large molecules, stabilized, and accumulated in the primitive ocean.
Biomolecules that make up a living organism include carbon, nitrogen, hydrogen, and oxygen as main constituents, and other elements such as sulfur, phosphorus. Carbon and nitrogen constitute the backbone of the biopolymer. Carbon has four arms that form a covalent bond, and nitrogen has three arms. Oxygen has two and hydrogen has one arm. Molecules are constructed in the way that these arms are fully connected. Compounds which have carbon skeletons are called organic substances.
A large amount of organic material exists in the universe. The Earth was supplied with a large amount of ice and volatile organic matter at the late stage of heavy bombardment of the meteorite, which was carbonaceous chondrite. Most of them are silicate minerals, containing metallic iron, ice and 2-3% of amount is organic substances. Carbon and water contained in the meteoroids in outer space are activated by ultraviolet rays coming from the Sun and particle beams to activate them, and a chemical reaction is caused to synthesize an organic substance having a simple structure.
Organic substances brought in at the time of the Earth construction would have been decomposed in the magma ocean era finalized by the giant impact. There would have been a lot of carbonaceous chondrite meteorites that fell after magma ocean era. Organic substances were possibly decomposed by the frictional heat with the atmosphere. Since the meteor that fell on the earth is simply an aggregate of sand-like grains, it decomposed at high altitude before the temperature rose, and the organic matter in the meteorite would be brought into the atmosphere without being decomposed.
In the ancient times there was no van Allen band due to the convection of Earth metal nuclei, charged particles coming from the Sun were striking directly on the upper part of the atmosphere. Experiments show that biomolecules such as many kinds of amino acids are often generated when high energy protons are irradiated to a mixture gas imitating the atmosphere of primitive Earth, which composed of carbon monoxide, nitrogen and water. Heavy organic matter synthesized in the sky fell into the sea by atmospheric circulations after condensed. Organic matters soluble in water reached the sea as rain drops. While falling with raindrops, there was a possibility that organic matter was concentrated through evaporation, and the polymer was synthesized during it drifted as a cloud. In the volcanic eruption, many lightning occurs together with reducing gas and water vapor. Reproducing this environment in experiments also made complex amino acids.
Amino acids and nucleobases are well studied as low-molecular organic compounds made first, because these are important components of living organisms. It seems that many other molecules have been synthesized, but they have not been studied much. Organic compounds with a molecular weight of about 1000 are discovered in large quantities from the biological world in large quantities. It also contains many useful substances, such as antibiotics. Amino acids and nucleic acids are molecules having about several to several tens of atoms with a molecular weight of 100-300. From these types of molecules, molecules with a molecular weight of about 1000 were synthesized and accumulated by catalytic action of high concentration metal ions in the hydrothermal vents at the bottom of the sea through thermochemical reactions. Those molecules contain multiple functional groups in one molecule and would assemble to form the base for a new chemical reaction.
Amino acids are synthesized through the famous reaction starting from aldehyde and hydrogen cyanide, ammonia. Besides that, decomposition of nucleic acid bases can be considered. Saccharides with simple structure can be synthesized from formaldehyde. The mineral consisted of boric acid acts as a catalyst. Although sugar has many three-dimensional structures even with the same molecule, among them, fructose, glucose, and mannose are stable, and it is considered that the sugar plays an important role in origin of life.
A cyclic molecule consisted with 6 or 5 atoms of either carbon or nitrogen, alternatively bound via single and double bonds, is called a hetero ring. Adenine, one of the nucleobases, has a heterocyclic structure in which hexagons and pentagons are fused. Adenine can be relatively easily synthesized from hydrogen cyanide and ammonia. Heterocyclic molecules containing nitrogen like adenine are bonded to each other weakly by hydrogen bonds and are easy to make complexes with metals. As it contains double bonds in a molecule, two double bonds react and tend to polymerize via radicals. Because it is easy to decompose with ultraviolet rays, the nucleobase is unstable at the surface of ground or in the sea, where the ultraviolet rays reach.
At bombing into the sea of a meteorite containing metallic iron, reductive atmosphere of ultra-high temperature was temporarily generated in the area. When a meteorite collides with the ocean, a large amount of water instantaneously turns into supercritical water and ultrahigh temperature gas, at the same time, the meteorite and the mineral components of the sea floor evaporated together and became a so-called after-impact steam flow. In ultra-high temperature post-impact steam flow, water decomposes into hydrogen and oxygen. Metallic iron and oxygen in the collision body reacted and became iron oxide. After the collision, the steam flow reached a reduction state of excessive hydrogen at once. Concomitantly, the iron sulfide and the peridotite were evaporated to work as reductive steam flow. As the temperature of the steam flow decreased from ultrahigh temperature, carbon reacted with the hydrogen generated to produce hydrocarbons and various other organic molecules. It is a chemical reaction known as Fischer-Tropsch synthesis and requires a transition metal such as iron, nickel, cobalt as a catalyst. These metal elements also evaporated at high temperature and coexisted in the steam flow.
Cyclic organic compounds having a benzene ring or a hetero ring are indispensable for basic molecules of living things. These organic substances are decomposed by ultraviolet rays. Elements of organic molecules were decomposed by exposure to ultraviolet light even when synthesized, in case in the sky or on the ground. The place where biological macromolecules necessary for living organisms were born, preserved, and formed higher-order structures (this is called chemical evolution) was on the ocean floor where ultraviolet rays could not reach.
The first candidate of the place of birth of life is around the hydrothermal vent on the seafloor. One of the reasons is that hyperthermophilic bacteria are located at the trunk (starting point) of molecular evolutionary tree. On the Earth in present, superheated bacteria are isolated from the hydrothermal vents of the seafloor. Other candidates, such as in volcanic activity on the ground (hot springs), collision of meteorites, and lightning, are lacking of stability in view of energy supply.
Seawater from black smokers formed in the hydrothermal area contains high concentrations of hydrogen. Hydrogen is generated when peridotites in the mantle react with hot seawater and turn into serpentine. In the proto-Earth, komatiite, formed by rapid cooling of magma, formed the crust, so komatiite is considered to be the source of hydrogen. At the present seafloor, hydrogen concentration of about 20 mmol is observed in the hydrothermal area originating from the ridge in the deep sea of 500 atm or more. Hydrogen is essential for reducing carbon dioxide to produce organic matter. An oxidation-reduction potential is formed around the hot water jet, thereby providing a fuel engine with stable performance due to a difference in concentration of a substance and a difference in temperature. It is convenient for the synthesis of organic compounds.
Furthermore, the seawater from the hydrothermal vent contains more than 1000 times more metal ions such as iron, manganese, copper, zinc than ordinary seawater. Metal ions act as a catalyst for polymerizing organic substances under high temperature and high pressure environment.
The hydrothermal vent is in an environment of high temperature (200-350 ° C) and high pressure (200-300 atm), and a large amount of heat energy is constantly supplied. Cold seawater infiltrated from the cracks of the ocean floor is heated in the bottom of crust, rises up the jet hole, blows out into the cold seawater, and is cooled again. The heating / cooling cycle of seawater occurring in the hydrothermal vents is reasonable when considering chemical evolution. Organic polymers that play a central role in life activities are unstable in high temperature environments. Organic materials synthesized at high temperature were immediately cooled at the sea bottom hydrothermal vent, so it was possible to avoid decomposition by heat.
As the sea water circulates, the organic molecules have passed through the hydrothermal vents many times over the flow and have grown into more complex molecules. Polymer compounds were filtrated from seawater containing organic matter when passing through mud, rock or crust, and being precipitated and concentrated there. For example, when considering that the reaction has progressed one step at each cycle, it fits well with the fact that the biopolymer is a linear homopolymer.
Biopolymers are generally linear homopolymers of amino acids, nucleobases, sugars. There are reports that amino acids and nucleotides adsorbed on the surface of clay minerals are polymerized, suggesting one of polymer formation mechanisms. In ancient times, low molecular weight organic compounds such as amino acids, nucleobases, sugars, fatty acids, hydrocarbons, etc. bonded to regular crystals (the surface of minerals) become polymers (linear homopolymers), this is one of theory on chemical evolution.
Another theory is to think about oil production. It is possible that sediment containing a lot of organic substances buried in the ground, undergo dehydration reaction under high temperature / high pressure in the underground, and turned into a substance like petroleum containing a large amount of unsaturated carbon bond. Petroleum-like low molecules tend to cause chemical reactions and easily polymerize at normal temperature and pressure. If a massive amount of organic matter was buried and became petroleum, it would have formed a layer like current petroleum and a high concentration of organic resources would have been generated.
Volatile organic molecules decompose with ultraviolet irradiation or such rays falling over in the sky on the primitive Earth. Nonvolatile organic molecules are dispersed in the sea. Molecules with small density and of water-insoluble like oils floated and agglomerated on the sea surface. In that case, it is decomposed on the sea surface where ultraviolet rays are falling or it is radical polymerized into a polymer. Water soluble molecules such as amino acids, nucleic acids and sugars dissolve in seawater, adsorb to clay minerals and precipitate on the seabed. In general, biological organic molecules have high affinity for clay minerals.
The hypothesis that life was born on earth has advantage in view of enrichment. Concentration of substances occurred on the surface from the tidal dry-wet cycle, which led to synthesis of macromolecules. The problem in pre-life evolution and chemical evolution is the mechanism of supply of macromolecules and how the combination and structuring of macromolecules to create life phenomena have been achieved. At present, several proven synthetic reactions have been reported, and it is likely that living organisms will be formed if they are conveniently combined. However, no matter how you describe it, the drawback is that it looks like expediency.
Ammonia and cyan produce numerous polymers containing nucleobases. As this process proceeds simultaneously, explosive types of compound are produced. However, under the presence of phosphoric acid, this reaction is limited to some extent. In the experiment, 2-aminooxazole is synthesized in the presence of phosphoric acid. This compound is a promising precursor of nucleic acids containing pyrimidines. Also, it is volatile and easily solidifies. That is, 2-aminooxazole is possible to be concentrate by increasing and decreasing the temperature. In the process of synthesizing a nucleic acid containing pyrimidine from 2-aminooxazole, there is no need to consider the reaction in which a sugar, a base and a phosphate group are bonded, which is one of the mysteries of nucleic acid synthesis on the primitive Earth.
Chlorophyll and hemoglobin (heme) are molecules in which heterocyclic molecules are coordinated to metal ions (magnesium for chlorophyll and iron for heme), to form complexes. Heterocyclic molecules such as nucleobases absorb ultraviolet rays and become activated. Molecules with many heterocyclic molecules, such as nucleic acids, are activated by visible light. Complex molecules composed of heavy metal ion and heterocyclic molecule were born on the ancient earth, and formaldehyde was made in large quantities from water and carbon dioxide by catalysis of metal ion activated by sunlight.
When carbon dioxide and hydrogen react with the catalyst of a heavy metal complex, formaldehyde is formed. Formaldehyde is a reactive substance and has the property of polymerizing itself, resulting in paraformaldehyde or a sugar. In addition, it reacts easily with chemical groups forming a hydrogen bond. As a result, intramolecular and intermolecular bond are formed. Molecules in living organisms, such as sugars, proteins, and nucleic acids, that make up the living body have abundant hydrogen bonds and react with formaldehyde.
To further imagine, the heterocyclic molecules-heavy metal ion complex, which produces formaldehyde from carbon dioxide using light energy, was linked each other by products, formaldehyde, then stabilized and accumulated in large quantities. I think this is the origin of photosynthesis.
Among alkaline liquids, formaldehyde undergoes a polymer synthesis reaction which produces various sugars. The macromolecule of sugar is insoluble and highly reactive.
On the other hands, the reaction that reduces iron sulfide with hydrogen sulfide to produce pyrite reduces carbon dioxide to form formaldehyde and formic acid. In the deep sea where sun light cannot reach, carbon dioxide assimilation by chemical energy spontaneously occurred. The iron sulfide produced as a result is insoluble and precipitates in the form of a foam. The catalytic center of carbon dioxide assimilation may be encapsulated in an iron sulfide capsule and serve as a source of cells. It is called the Hall & Russell hypothesis.
Compounds having high energy as chemical bonds are necessary for enzymes to carry out synthesis reaction under the body temperature. Current cellular organisms utilize molecules that can carry an active state as chemical bonding energy. It is adenosine (a molecule that is a nucleobase adenine and pentose bound). Adenosine triphosphate (ATP) carries high-energy phosphate bonds and NADH and NADPH carries redox state, both contain adenosine.
The high-energy phosphate bond of ATP seems strange molecule in which three phosphate groups are connected in series. When phosphoric acid is heated, a dehydration reaction occurs, and two or three phosphoric acids react at 200-300 ° C to produce pyrophosphoric acid (diphosphate) and polyphosphoric acid. It is easy to decompose in aqueous solution, but it is synthesized as a polymer compound in hot water. The process is unknown to use phosphate groups for biochemical reactions in chemical evolution. Considering the principle of biological evolution that one uses matter available there, adenosine and phosphoric acid would be abundant in the place where life was born. In addition, at the hydrothermal vent, where considered as a place of life creation, polyphosphoric acid is synthesized in the underground of high temperature region if phosphoric acid is abundantly dissolved. Polyphosphoric acid was used as an energy source for chemical evolution where injected into the seawater in a moderate temperature range. ATP appears everywhere in biochemical reactions. Coenzyme, which is a small molecule that works at the active center of the enzyme, also contains heterocycles (heterocyclic compounds) consisting of adenosine and carbon and nitrogen.
There are many reactions in vivo that bind phosphate groups through chemical reactions to the substances for further processing. For this purpose, the carrier of the phosphate group is ATP and other coenzymes and vitamins. A glycolytic system for metabolizing sugars is a typical example. In addition, FADH and NADPH, which are carriers of protons (hydrogen ions) and electrons in the redox reaction, contain phosphate groups.
Furthermore, a group of molecules containing sulfur is also involved in energy production and polymer synthesis. The iron sulfide complex is located at the active center of the enzyme at the entrance of the TCA circuit, which locates at the center of energy production. Sulfur-containing coenzymes provide methyl and acetyl groups. The skeleton of these coenzymes is a heterocyclic molecule composed of carbon and nitrogen, and is composed of 1 to 3 heterocyclic rings. Since there was almost no oxygen on the molecule in the Earth of the Hadean eon, heterocyclic compounds were rarely decomposed by oxidation.
Sea water containing a large amount of iron ions, phosphate ions, carbon dioxide was circulating through the crust around the hydrothermal vent. Around the heat source at the bottom of seafloor, the temperature is high, and in the reducing state, precipitates of metal ions and molecules containing high-energy bonds are formed. Since the temperature of the seafloor is low and being the oxidation state there, high-energy bond was converted into covalent bond between molecules. The non-equilibrium state which is the energy source of life activity was maintained in the temperature gradient and redox state.
My hypothesis is that the foundation of chemical reaction was initially the surface of minerals, but eventually developed to the surface of macromolecules containing heterocycles, and further to the surface of proteins (enzymes). As the activation energy is lowered by the catalytic action, the driving force of the chemical reaction by the temperature gradient was taken into the cell, and evolved into a modern life activity, which does not require a high temperature to work
The mystery of the origin of life lies in the dilemma that the genetic system cannot function unless it would be formed at once. Proteins cannot be made simply after amino acids appeared. That is, even if a monomer of a biopolymer is formed, a polymer cannot be formed. Molecules necessary for living activities should have been born by numerous chemical reactions. Molecules with autocatalytic ability capable of synthesizing themselves by themselves should have accumulated in large quantities. Molecules that produce themselves can be considered to carry genetic information. In current organisms, responsive molecule for genetic information and for function are different. In this case, genetic information does not function without a device for reading genetic information. It cannot be said to be inherited if impossible to synthesize (replicate) the molecule responsible for genetic information. This leads to a discussion on whether chicken or egg is ahead.
Therefore, first of all, consider a mechanism (catalyst molecule) that binds units one-dimensionally. The unit has functional groups for two chemical bonds. If no rule, just a random polymer is synthesized. In order to have information, it needs a link between the sequence of the units and the synthesis system (catalyst). The link is a mechanism that the order of synthesis of unit molecules is designated by sequence information. This is a replication device. The information of sequence is included in the one-dimensional array of the molecule.
Specifically, a reaction is conceivable in which a hetero ring forms a pair using hydrogen bonding. It is the same as the nucleic acid which is the main body of the current genetic materials. The machine specifies an sequence of newly synthesized molecules by making a pair. In the course of chemical evolution, nucleoside molecules are made, they are aligned in a row by stacking interaction of nucleobases, and if they are bound to an appropriate catalyst surface, phosphate group and ribose can bind to synthesize RNA. At this time polyphosphoric acid is involved as a catalyst and energy source. RNA molecules can make three-dimensional structures due to stacking interactions and hydrogen bonding between nucleobases. Due to the complementary relationship of hydrogen bonds, RNA has the property of pairing with a fixed base.
One of the currently known functions of RNA is an enzymatic reaction. It is known that an RNA molecule having a specific sequence cleaves a molecule, and an RNA having another sequence binds RNA. They are called ribozymes. In a ribozyme, an active site that causes a chemical reaction is formed by assembling heterocycles by arranging nucleotides in a certain sequence.
When a ribozyme, which facilitates the synthesis of its own complementary nucleotide, happens, it uses the nucleotides in the environment to increase its number. This is a positive feedback reaction pathway. One ribozyme catalyzes one chemical reaction, but the continuous arrangement of ribozymes connects the catalytic reactions, and a mechanism can be created in which molecules flow into the molecule and are processed into complex molecules. And ribozymes capable of replicating ribozymes were born after a long time by miraculous chain of events. Once such a positive feedback reaction pathway has been formed, it has become possible to synthesize the parts of living organisms as subspecies.
Molecular complexes able to replicate and grow on a special catalytic surface have come to have the complexity and some scale enough to replicate themselves after a long time. This is called a two-dimensional life form theory. The problem is that two dimensional life forms lose their lives when they detach off from the catalyst surface. Was there a possibility that integrity was established not to lose life? No, it is too complex to be possible. There is no other way than to confine it in the vesicles.
A complex molecule formed by complementary pairing is conceivable, which has a function of synthesizing a nucleotide. Once such independent molecules are formed, the two-dimensional life can leave the surface. An ancestor of ribosomal RNA which plays an important role in protein synthesis system is thought as one of such complex molecules.
When a heterocycle containing carbon and nitrogen is cleaved, it becomes a molecule having an amino bond. If a part of the composite polymer linked with hydrogen bond is cleaved, electron transfer of the double bond occurred to form a linear oligopeptide. I present the hypothesis that such an oligopeptide binds to the end of a heterocyclic molecule, which has evolved into a protein synthesis system. This heterocyclic complex is considered to be an ancestor of transfer RNA.
During about 1 billion years after the birth of the Earth, the atmosphere and the sea were agitated violently by the tidal action of the moon which was very close to the Earth and impacts of meteorites. The molecules that constitute the living body had been steadily accumulating. Hundreds of plates are crowded together on the Earth's surface in the Hadean eon. The plates collided, but both were so young plates that subduction hardly occur. The plates were folded to upraise at the subduction zone. The magma was not formed from the plate that had slipped under another plate as the present day. The plates were bent and pushed into the mantle, then became magma in the deep. In this case, a folding mountain range was formed at the plate boundary, and a volcano is formed in the center of it. The magma was compressed from both sides and spouted out to the sea, forming islands. Arc-shaped islands formed and grew along the plate boundaries.
The ocean current which had become a laminar flow along the latitude was to be stopped at the arc-shaped islands. The seawater which had been circulating independently at the surface and in the sea floor has welled up and settled down at the arc-shaped islands. Also, the waves that hit the rocks at the shore broke and flew away as droplets. The organic matters synthesized at the bottom of the ocean traveled all the way to the sea surface, splashed at the sea surface and flied up to high altitude. They chemically reacted with the organic matters which synthesized at the sky, resulted to form other type of organic molecules there. Then the insoluble minute organic matters fell to the surface of the sea as rain and sunk and returned to the hydrothermal vent. Organic synthesis was accelerated by ultraviolet light in the sky, and also received moderate decomposition.
The volcano rising in the sea were blowing a plume up, and supplying fine particles to the atmosphere. The fine particles became the core of cloud water droplets, and the Earth was covered with clouds more than before. Clouds cut ultraviolet rays that decompose heterocyclic compounds. Since the sun's radiation at that time was weak, the Earth may have been covered with ice globally. Heterocyclic compounds may have been able to convert light energy to chemical energy under ice without being destroyed by ultraviolet light.
Well, this chapter is just my guesses. How much was the concentration of carbon in the primitive Earth? First, considering the current amount of water in the sea is 1.35 billion km3 and the total carbon circulation amount on the surface of the earth is 50 trillion tons (both values are from Wikipedia), the concentration of carbon is assumed to be about 3.6%. Second, assuming the depth of the primitive ocean 2000 km, and the current crustal weight of 2x10E16 tons and the proportion of carbon contained in crust is 0.03%, the proportion of carbon dissolved in the sea as 1%, the concentration of carbon in the primitive sea is assumed to be 6.6%. When referring to the water content of silk tofu and milk is 90%, the sea of the primitive Earth may have been muddy with organic molecules more than expected.
At the zone of mantle plume, an ocean ridge is formed and hot water spouts up as a line. They were at the deep sea floor of 2000 m. In the place where the plate collided, magma warmed the seawater and also formed a hot water spout (a hot spring). This place was at depth of about 100 m at the shallow sea bottom near arc-shaped islands. One hypothesis on the birth of life would be here a hot water spout at the shallow sea floor. Caldera volcano under the sea was pushed from both sides and gradually uplifted, became a bay and finally became a lake. From the speed of uplift of the Himalayas and the Alps, it will be landed in tens of millions of years. This process poses a hypothesis that sufficient enrichment for birth of life would have occurred during this time. Presumable primitive life organisms born in the volcano lake would have been returned to the mother sea.
The way to understanding on the birth of life is the accumulation of hypotheses. Note that it is an imagination. Up to chapter 19, I introduced chemical reactions supposed in the natural world which biomolecules were formed. I would like to step into details a little more, but I should have been creative in writing. The story will be a professional one including organic synthetic chemistry and biochemistry. In Chapter 20, I discussed the possibility that the accumulated organic substances turned into macromolecules, via concentration and mixing on a global scale. Based on these assumptions, I imagine that a chemical reaction system survived that can evolve into an organism. I point out that the story after this chapter will be closely professional of cell biology and molecular genetics.
The survived chemical reaction system is represented by autocatalyst. If a chemical reaction catalyzed by a molecule can synthesize itself, this molecule is an autocatalyst. In other words, it means that the product of the chemical reaction is its catalyst for the reaction. Chemical reactions are reversible. When the raw materials disappear, the products are decomposed and returned to the raw materials by the same catalyst. Therefore, after a long time, the concentrations of the raw material and the product become constant at a certain ratio. This is called chemical equilibrium. Which molecule is larger depends on the difference of the enthalpy and entropy between the raw material and the product. In this situation, the chemical reaction will not acquire the purposefulness like living things.
One of the situations in which chemical reactions acquire the mechanism of life is flow. The situation is such that the raw materials continues to be supplied and the product is carried away by the flow. Organisms has a limited volume, so they take in nutrients and discard waste products. In addition, raw materials are taken into the cells, and the concentration of the product is adjusted by a continuous processing line so as not to increase. Biopolymers have a higher enthalpy and a lower entropy than raw materials. Thus cells require energy for biopolymers to be produced.
Organisms realize a device similar to that. That is, the enzyme that catalyzes the reaction for binding amino acids is a polymer of amino acids. However, sequence information of the protein synthase is stored in DNA. Then, a DNA replicase that duplicates DNA sequence information is required. It is reasonable that DNA is recorded by itself as a specific pair of nucleotides. The protein synthase makes its own replicas with reference to DNA sequences, and also makes DNA replicase. The smallest organism is composed of two genes and two enzymes.
Let's add the flow to the smallest creature hypothesis. One DNA with two genes and two kinds of enzyme must be in the same place. The amino acids and nucleotides used as the raw material are supplied along with the flow. Amino acids and nucleotides have lower enthalpy and higher entropy than DNA and enzymes, so DNA and enzymes need energy to be able to form. Then, a mechanism for supplying energy is needed. I explained that the energy currency of living organisms is ATP. From the above, an enzyme that supplies ATP is needed, and also a scaffold protein that keeps the DNA and the enzyme in the same place. Thus the types of genes and proteins required are increasing.
The story to the birth of a cell needs a hypothesis that can explain this process well. By the way, in today's organisms, protein synthase is a complex consisting of dozens of RNA molecules and dozens of enzymes, and DNA relpicase is composed of several types of core enzymes and enzymes with dozens of auxiliary functions. Modern sophisticated enzyme complexes are thought to have evolved after the birth of the simplest genetic mechanism.
Cells are separated from the outside world by cell membranes. Cell membrane is one of basic structures of independent form of life. The membrane component is lipid. There are two types of lipids in the cell membrane of the present organism. One is a phospholipid, which is used by eukaryotic cells and many bacteria. The other is isoprenoid ether, which archaebacteria, especially thermophilic bacteria utilizes this type of lipid. The membrane of isoprenoid ether is so hard that the membrane shows moderate fluidity only at high temperature. As to the origin of life, this type of lipid may be its original form.
Isoprenoid ether has ether bond between isoprenoid and glycerol-1-phosphate. Since glycerol-1-phosphate is bound to both ends of two isoprenoids, the length of the isoprenoid determines the thickness of the membrane. Isoprenoid is a polymer of isoprene monomers composed of five carbons. Eight isoprenes are polymerized to reach to the thickness of archaea membrane. It is unknown how isoprene was synthesized on an ancient Earth. It became a cellular structure, so it must have been a common organic matter.
In the present living organisms, isoprene is synthesized by decarboxylation and dehydration reaction of mevalonic acid, which is polymerized three acetyl groups on the base of coenzyme A (coenzyme A) under the catalytic enzyme (mevalonate pathway). Coenzyme A is a molecule based on adenine nucleotides, and isoprene becomes water soluble by added two phosphate groups. Another pathway is a reaction combining pyruvic acid and glyceraldehyde, involving a number of heterocyclic compounds such as cytidine nucleotide and NAD, through a deoxyxylulose-mediated pathway.
By the way, the fatty acid which is the constituent material of the other cell membrane is made on the basis of coenzyme A on a complex enzyme (8 proteins in bacteria, a big protein complex in eukaryotic cells).
Since isoprenoid ethers have phosphate groups at both ends, they spontaneously assemble into a sheet in aqueous solution. Initially, cellular elements grew in vesicles surrounded by sponge-like minerals composed of fine silica fragments generated under high temperature and a high pressure, or iron sulfide precipitated in the form of bubbles. The membrane made of isoprenoid ether kept the components in the protobiont cell from diffusing outside, and the element of the protobiont cell was stabilized. As the membrane has many holes, so protobiont can exchange materials through such small holes.
The autocatalyst that makes the membrane structure binds to the two-dimensional membrane and catches isoprenoid ether and has the function to add it to the two-dimensional membrane. Many kinds of reaction pathways that produce biomolecules or chemical energy and physically take substances into the protobiont cells are encapsulated in the membrane. The isoprenoid ether membrane grew bigger and bigger, and tore to split appropriately. At this time, the aggregate of autocatalytic molecules in protobiont cell was randomly divided into two. The protobiont cells with a pseudo-membrane structure were fused to capture the complex that undergo different chemical reactions and acquired the ability to synthesize nucleic acids, small molecules, and macromolecules. Although the enveloping process is random, it has continued to increase in volume and the ability to duplicate various complexes were formed.
There is little evidence of chemical evolution of the isoprene synthesis system. Also, current living organisms have a mechanism to produce ATP by chemical osmotic pressure through biomembrane, but its origin is also unknown. Both are essential to consider the origin of the cell, but at present there seems to be no good hypothesis.
Phospholipids making up the cell membranes of living organisms today are a tough barrier to polar and charged molecules. Cells need complex channel or pump proteins in order to exchange molecules with the external environment. Cell membrane had started with isoprenoid ether as a main constituent. After that, probionts invented a membrane made of phospholipids (fatty acids) then adapted to a lower temperature environment.
LUCA (Last Universal Common Ancestor), a common ancestor of current organisms, is a top-down approach inferred from gene phylogenetic trees. Conversely, there is a bottom-up approach to non-biologically reproducing biological entities from chemical evolution studies. The latter has no symbolic name, but is called here as FLOQES (First Living Organism in Quasi-Equilibrium State) according to the JAMSTEC hypothesis. There would be a time gap between them. Further fossil evidence suggests a common ancestor OFC (Oldest Fossil of Cell). Since LUCA is not always found as a fossil, there would be a time gap from LUCA to OFC.
From the astrobiological schematic, FLOQES is common to the universe, and then LUCA is environment-specific. Environments in which terrestrial life is born include terrestrial planets, terrestrial satellites, aquatic planets, aquatic satellites, and artificial environments.
According to the law of thermodynamics, the Universe has been cooling and the entropy has been increasing. In that process, matter was born as an entity that stored energy, and matters gathered to form a celestial body. The matters can eventually be described as a temporary stagnation of the flow towards equilibrium. A substance undergoes a chemical reaction, turning into a molecule of lower energy state according to the laws of thermodynamics. At that time, the chemical reaction does not follow the shortest route to the equilibrium state, due to the types of molecules involved and the heterogeneity of the environment. Sometimes detours. Creatures have begun to walk as a collection of such detours.
For example, when a precipitate is formed, a process of dissolving the precipitate is necessary to reach an equilibrium state. The precipitation is an example of a detour. When a layer of substance is formed around the precipitate, the precipitate becomes difficult to dissolve. This is also a detour. Given a membrane-enclosed system, an additional detour is provided by the transport and accumulation of material inside the vesicle. An additional detour is born if a chemical change occurs inside the vesicle on the material that prevents it from passing through the membrane. The formation of a cell membrane facilitates the integration of chemical reactions as detours.
As can be seen in the example of fossil fuels existing on the present Earth, it would have occurred in the ancient earth that large amounts of organic matter precipitated, accumulated and concentrated. However, even though a lot of organic matter existed in one place, it is difficult to think the new life was created from a mere lump of organic matters. The autocatalytic reaction was discussed in the previous section. I also argued that cells with membranes can preserve a set of autocatalytic enzymes.
There is a concept that a protein molecule has a structure composed of an autonomous element of about 10 to 20 amino acids and the remainder that enhances the performance of the autonomous element. Because primordial proteins formed early in chemical evolution are considered to have evolved under high temperature, small and stable autonomous elements were advantageous. Of course, its reaction specificity was lower and its catalysis is slower, than modern enzyme. That is, they are unstable, and error-prone compared to the current enzyme. The existence of autonomous elements themselves can be thought of as a remnant of primitive proteins.
Since primitive organisms had only the minimum genes (enzymes) necessary for life activities, the substrate specificity of the enzyme is thought to be much broader than the present enzyme (recruitment hypothesis of enzyme evolution). In the course of subsequent evolutionary diversity, these genes duplicated and mutated, eventually acquiring stricter substrate specificity than ancestral enzymes, accompanied by a complicated metabolic pathway.
A gradient of redox, temperature, and/or pressure are formed in nature, and molecules flow along the gradient there. A pool is formed where organic matter accumulates in the gradient, and it is roughly covered with a membrane. Imagine that complex organic matters crowded in gaps of a structure such as a filter or a sponge, and soup composed of organic precursors flow in interspace of them. In the primitive ocean, there are numerous vesicles (protocells), like the prototype of Solaris' s sea. There is a living body with a size of macroscopic, which acted as one organism. They would have been the ancestor of the cellular organisms. Many primitive genes, catalytic reactions, anabolic reactions by chemical energy, enzymes were incorporated within them. It is more advantageous to adapt to the changing environment. I call them protobiont organism, FLOQES.
FLOQES were formed at the chimney of the hydrothermal vent and those of the submarine volcano. When by acquiring the ability to synthesize a membrane, a part of the FLOQES torn off and flowed into the sea, which became the prototype of the cell. They were discovered as the OFC.
The Archaean era has started since 3.8 billion years ago.
The birth of the Earth is 4.6 billion years ago. After the late heavy bombardment period, the atmosphere and the sea stabilized since 3.8 billion years ago. The oldest sedimentary rock ever confirmed is those of 3.8 billion years ago. The oldest cell fossil was 3.5 billion years ago. The carbon component (molecular fossil) which seems to be the oldest biological origin was extracted from the stone of 3.8 billion years ago in Greenland.
The oldest fossil of the cell is thought to be a cyanobacterium of 3.5 billion years ago, discovered from the sedimentary rocks of the Pilbara Formation in Western Australia, Fig Tree Group of Transvaal Province, South Africa. The traces of Pilbara microorganisms were contained in the sedimentary rocks formed around the hydrothermal vent in the submarine that existed at depth of 2000 m about 32 to 3.5 billion years ago. It is powerful evidence that hydrothermal vent is one of candidates of origin of life.
A 3.5 billion-year-old geological body in the North Pole area west of Australia. A sedimentary layer overlies the oceanic crust at that time. You can see its cross section. White dikes run in the ocean crust. They are passages of hot water at that time. The silica dissolved in the hot water was precipitating as quartz in the process of mixing with cold seawater and filling the passage. A number of black lines with a thickness of about 10 μm are observed around the dike. It is a substance made of carbon, which has been identified as a microbial fossil 3.5 billion years ago. This microorganism was presumed to be a thermophilic methane bacterium that fixes nitrogen.
Molecular fossils derived from photosynthetic organisms are distinguished by preferentially incorporating carbons with a mass number of 12 over those with a mass number of 13. The 13C / 12C isotope ratio of biological carbon is smaller than that of inorganic matter. Examination of the isotopic comparison of sulfur in the sea deposit of 3.5 billion years ago found from Australia revealed chemical synthesis using hydrogen sulfide (similar process to photosynthesis).
A more direct evidence is extraction of the biomarkers. As a typical case, lipids (steroids), which are main constituents of the cell membrane, remain as molecular fossils as maintaining the molecular structure specific to certain biological lineage. In the verification of molecular fossils it is estimated that prokaryotes existed 2.7 billion years ago and cyanobacteria also existed 2.7 billion years ago. The steroid, a molecular fossil of 2.7 billion years ago, is one of isoprenoids.
I assume that perhaps incomplete cells appeared 2.7 billion years ago. By assembling a large number of these cells, they produced metabolites, exchanged each other, supplemented and survived. Primitive cells should have formed a population and loosely bound as a community. The new invention of one constituent cell upgraded the ability of the whole community. In the community, each cell unit replicated, broken up properly and divided, and increased their number.
The first survival competition is thought to have taken place between individuals with a different mechanism from modern organisms. And a common ancestor of protobionts with one mechanism survived (the Last Universal Common Ancestor). However, is it assumption from the modern theory that organisms should be consisted with individual cell? Immediately after the creation of an organism, although it is partitioned by the cell membrane from external environment, it is unlikely that they have a mechanism (protein = gene) to identify individuals.
Given that the modern cells which have the same gene replication and gene expression mechanism as the current organism was born 3.8 billion years ago, based on the speed of evolution in the last one billion year, mammals (or organisms with the same ability as that) would have been born around three billion years ago. Despite the accumulation of accidental mutations, the evolutionary rate predicted from the modern genetic machinery is high. Of course, there is a possibility that an intellectual life had evolved to human level in the past. But such an intellectual life would have changed the earth's surface "unnaturally" by activity, so that its traces would have remain.
According to the RNA world hypothesis, a mechanism has been created to functionally complement the mechanism of gene replication and enzymes. Its basic component is RNA-protein complex such as ribosome. Ribosome of current organisms is a complex composed of 50 kinds of proteins and at least 3 types of RNA molecules. If these structures and functions came up with try and error, it would not seem quite accidental (= spontaneous). Besides that, the splicing device and the RNA virus replication intermediate are also an RNA-protein complex.
It is difficult to imagine that the ingenious mechanism of the living organism was naturally formed. The intelligent design theory, saying that an advanced intelligence created the living organisms, defines such an advanced intelligence as God. The intelligent design theory mentioned a bacteriophage as an example. Certainly, it is hard to believe that advanced molecular machines, bacteriophages were created by accident. However, many bacteriophages were discovered and analyzed, and it can be concluded that bacteriophage, a sophisticated molecular machine, could also evolve as a result of mutations and natural selection. In other words, the evolution is fast if the genetic mechanism is established. Conversely, it is expected that there will be a long history of trial and error until the genetic mechanism is created.
I think that the foundation of a mechanism for functionally complementing the mechanism of gene replication and enzymes in RNA world was completed during about one billion years from 3.8 to 2.5 billion years ago (= beginning of Archean era). We must propose a hypothetical process in which a mechanism to provide proteins with appropriate performance during this one billion years.
My hypothesis is that nucleobases provided proteins. Nucleobases, when moderately cleaved, become oligopeptides. Nucleic acid bases are sequentially arranged on the RNA molecule, making a pair by hydrogen bonding. The heterocycles or nucleobases are cleaved, and bind each other with a nearby nucleobase through reaction energy, so that a somehow large peptide can be formed. Also, there was a suitable catalyst for cleaving the nucleobase (there is no evidence for this reaction). RNA that decomposes to provide the peptide which catalyzes the replication function is advantageous as compared with those replicating by catalytic action of its RNA. RNA that produces peptides that catalyze its own replication will increase in number in the RNA world and should dominate in evolution.
The sequence of the oligopeptide depends on the sequence of the nucleobase. Various oligopeptides were born according to the sequence of RNA. As long as the peptide is not degraded, it accumulates in the system and continues to catalyze the reaction. Oligopeptides complexed with RNA and/or other oligopeptides provided the complex catalytic reactions. Among the oligopeptides, set of molecules that catalyze reactions that provide their own materials prominently progressed and begin to evolve, that is, reactions that synthesize RNA, and thus reactions that provide parts of RNA. The self-proliferating complex molecules and their gene sets are easy to imagine as virus that created replication and translation mechanisms in primitive cells. However, the current virus relies on protein synthesis for ribosomes. Whether peptides / RNA complexes responsible for their own synthesis / replication have evolved as generalized functional structures, and established ones were protein synthesis systems containing ribosomes.
Ancient mantle convection was divided into two layers. The upper layer had a thickness of about 670 km and became a turbulent flow. The convection was almost circular, and a plate of almost the same size was on it. The plate is about 700 km in diameter, and it can be calculated that the number of plates on the whole surface of the earth was about 200.
An ocean ridge was formed where the convection rose up, and an archipelago was formed where the convection sank down. The depth of the ocean was probably 2 km. Since there was no continent, the depth of ocean was almost uniform. If the movement of the plate is 3 cm per year in speed, one plate will enter into the mantle in about 20 million years. At that time, a lot of addenda were left on the archipelago.
At first the temperature of the upper mantle was high, and the subducted plate was melted (phase transition) and assimilated with the mantle. As the temperature of the whole earth gradually declined, the subducted plate came to accumulate at the bottom of the upper mantle with the center of low temperature. Finally, the largest lump of the subducted plates submerged, then passed through the internal mantle, and finally reached on the surface of metal nucleus. It was 2.7 billion years ago.
This cold mass induced a difference in temperature in the metal nuclei which had been uniform, then a convection occurred inside the metal nucleus. Convection produced a flow of free electrons (current), so Earth dynamo was born. Earth dynamo created a magnetic field. The Earth became surrounded by a strong magnetic barrier from 2.7 Billion years ago, and the solar wind containing the charged particles dangerous to life did not reach the surface of the earth. Cyanobacteria, which had been able to evolve into the shallow sea, prospered greatly using solar energy.
The subduction of crustal lumps that switched on the dynamo of the Earth's core united the mantle convection that had been divided into two layers. The amount of rock rising from the interior of the earth is equal the amount of rock to sink. For that reason, heat from the mantle inside the Earth was efficiently carried out to the Earth's surface, and volcanic activity became active.
Also, as the diameter of the mantle convection increased to 3000 km, the size of the plate also increased, the arcuate islands that had been scattered up until now are gathered, and gradually large land is formed. In this way, the first kraton was born. Kraton is an old continental land stable for more than 500 million years, mainly composed of granite, estimated to be 200 km thick. The oldest kraton has a history of more than 2.5 billion years.
The plate masses accumulated under the small continent became a huge cold plume about 1.9 billion years ago, then the plates were attracted that had been scattered on the surface of the earth. Collision, addition, and coalition of arcuated islands on the Earth, eventually a huge continent was born. An orogenic belt was created between the old kratons of which the oldest one was about 1.8 billion years old. It is the era of the first supercontinent. The first continent is called Laurencia (Nuna). The first supercontinent was the combination of the current North American continent with Greenland, the Scandinavian peninsula, the Australian continent, and the eastern Antarctica. The area is estimated to be as large as the North American continent in present days.
Mantle convection induces movement of the plate covering the earth's surface. Plate motion is directly observed as speed of several millimeters to tens of centimeters in one year using GPS and other technologies. As a speed of roughly 3 cm per one year, a mass was risen up over about 100 million years traveling through 3000 km from the core surface to the surface of the Earth. On the contrary, when a cold plume occurs, it takes about 100 million years for the tip to reach the core, during which 3000 km square plate is drawn. Since the circumference of the Earth is 40,000 kilometers, after the cold plume occurs, roughly 600 million years ago, all the plates gather at the place of the cold plume = an ultra-continent would be formed. Wilson cycle is faster than this calculation.
The mantle overturn occurred at 2.7 billion years ago and the first supercontinent was formed at 1.9 billion years ago. These periods shows the highest volcanic activity throughout Earth's history . Volcanic activity created a large amount of magma, which became the base of the continent. During this time, photosynthesis was evolved, which releases oxygen, and cyanobacteria were born. It is estimated that 2.3 billion years ago, global freezing occurred and caused massive extinction of living things. As a result, it appears that eukaryotes appeared 2.1 billion years ago. In the African continent and its surroundings, small continent collisions occurred 2, 1.1, and 0.7 billion years ago, and gradually grew to a larger continent. The last collision shaped southern Africa and is called the Damara Orogeny.
Virus has been thought to originate from fragments of genes escaping from cells. However, when phylogenetic trees are constructed by comparing DNA or RNA replicases, the viral enzymes are located outside the three domains of eukaryotic cells, archaebacteria, and eubacteria. Therefore, it seems that there were many types of nucleic acid replication enzymes, as typified by viruses, before cells were organized into three types. Although the age is unknown because an accurate evolutional clock cannot be made, which demonstrates a longer history of its origin.
Mammalian and plant viruses have only the genes of protein capsules housing its nucleic acids, the genes required for nucleic acid replication, and the genes needed to parasitize cells. The smallest virus has only three genes, whereas the largest one has about 100 genes. Viruses rely on ribosomes for protein synthesis. After the ribosome evolved as a device for synthesizing proteins, the virus would have been established as replicating organisms and would have begun its own evolution. Viruses are the inhabitants of the RNA world.
The replication enzyme of the gene possessed by the virus has all combinations, one that replicates RNA using RNA as a template, one that replicates DNA using DNA as a template, and synthesizes DNA using RNA as a template. Cells commonly have enzymes that synthesize RNA using DNA as a template. Since the first replicable molecule is expected to be RNA, organisms that have RNA as genomes should also contain viruses.
Virus propagation is just a chain of events. That is, the process of its proliferation is written into its genes step by step. Cells have material fertility that can support the growth of the virus. Before the birth of the virus, that is, before the formation of cells, there must have been an environment with sufficient material abundance to allow the virus to survive. In addition, the virus must have carried out activities to create an environment favorable to its survival. The big fruit might have been a cell. When exposed to competition with cells, the virus armed with its small genome size by replicating quickly and having a high evolution rate.
The virus evolved RNA dependent DNA synthetase (reverse transcriptase). And at that time, there is a possibility that viruses took over the replication mechanism of the cell that had used RNA as a gene (From the cell's point of view, the cell uses the virus to convert its own genome into DNA). Given that this hypothesis is correct, the DNAization of genes is before cells divide into three domains. Poxviruses create a membrane-covered structure in the cytoplasm, replicate in it, and synthesize mRNA. This function is equivalent to the cell nucleus. Perhaps the nucleus of a eukaryotic cell might be derived from a giant virus such as a poxvirus.
Among viruses infecting protozoa, there are viruses with genomes of a size comparable to small bacteria. The giant virus develops nucleoid in the cytoplasm of infected cells like a poxvirus. These giant viruses contained metabolic enzymes (viruses do not metabolize) and genes for biosynthesis. Comparing these genes with eukaryotic cells and bacteria, the branch time was estimated to go back at least 2.7 billion years ago. However, since it is also presumed that the large virus has taken up the host cell gene, estimation of the origin needs further examination.
From the study of bacterial viruses (bacteriophage) it was known in the 1970 's that viruses take fragments of genes when they infect cells, then they bring the fragments into the infected cells. In mammals it is thought that retroviruses have played a role in carrying genes. Also, the virus replicates in the genome and 20% of the mammalian genome is presumed to be derived from the virus. Those gene fragments are not functioning. In some cases, the fragments derived from viral genes have functioned and assumed to contribute to evolution of host organism.
Focusing on genes shared by all living organisms and measuring their molecular evolution, we can calculate the time when the first organisms were born. Nucleotide sequence of ribosomal RNA was examined first. Ribosome is a protein-synthesizing machine universally possessed by cells, is well conserved, and contains RNAs as a constituent. Ribosomal RNA is also encoded in a genome DNA.
The oldest organism in the phylogenetic tree made from the nucleotide sequence of ribosomal RNA is the prokaryote, yet it is the eubactrium. Archaebacteria branched about 1.8 billion years ago. The archaebacteria grow in extreme environment; halobacteria in high salt water, acidophilic bacteria living in extreme acidic environment, and thermophilic bacteria adapted at high temperature of 100 oC. Subsequently, eukaryotes emerged from this group 1.5 billion years ago, when the simple cellular structure of prokaryotes changed to complex eukaryotic cells. A part of proteins (genes) of eukaryotes, of mitochondria and lysosomes are derived from eubacteria.
However, when using another gene, the archaebacteria may come to the root. The phylogenetic trees that the eubacteria are close to the primordial organism are provisional. Not the individual genes but the results of the analysis of the entire genome ongoing to be analyzed now will give a surprised result. In any case, prokaryotes are organisms that make up the majority of the molecular phylogenetic tree, and other animals and plants are only one of the small branches. Biochemical diversity in prokaryotes is the most prominent.
Regardless of archaebacteria or eubacteria, the root organism of the phylogenetic tree is a thermophilic bacterium. Life began at the bottom of the hot ocean, and it is thought that it divided into archaebacterium and eubacterium under hot environment.
Deduced from molecular phylogenetic tree techniques, and restored proteins experimentally, ancestral proteins were more heat resistant. Therefore, it was suggested that the ancient life inhabited under the high temperature environment. Furthermore, when estimating the ancestral type of elongation factor proteins of more than 25 kinds, they were highly thermostable. The circumstance of ancient life was suggested that the temperature gradually decreased by 30 oC until 500 million years ago.
Of the 4288 genes found in the E. coli K12 strain, there are only 303 genes necessary to grow in synthetic medium in the laboratory. Also, if you classify genes from their functions and sequence similarity, universal genes will be 200. Because there are also extinct genes, it is estimated that 1000-1500 genes were worked at the time when an independent living organism was established.
Researchers from Denmark University reported an analysis of 61 E. coli genomes in 2010. The pangenome of E. coli contained 15,741 genes, with only 993 core genomes (6%). From these results, it was found that E. coli also obtained genes by horizontal gene transfer from microorganisms distantly separated in phylogeny.
In addition, researchers at the University of Dusseldorf compared the 537,923 genes in 181 prokaryotic genomes and examined the horizontal movement of genes. As a result, 80% of the genes were thought to be moving horizontally. Therefore, the phylogenetic trees of bacteria were considered to be in the form of a mesh or a net considering of vertical transmission and horizontal shift of genes.
When we placed the energy acquisition method for carbon dioxide assimilation onto the evolutionary phylogenetic tree made from the ribosomal RNA genes, what appears first is photosynthesis that does not generate oxygen. Photosynthesis has two reaction center complexes, type I and type II, but the early bacteria have only one of them. Cyanobacteria have both photosynthetic reaction centers and appeared later. Cyanobacteria are gram-negative eubacteria. Among Gram-negative bacteria, the branch point of cyanobacteria is quite old in the phylogenic tree. Since cyanobacteria are the first organisms that have a powerful photosynthetic mechanism, it is speculated that they boasted overwhelming proliferation power. Even today, there are many species of cyanobacteria, their habitat environment is vast and have symbiotic relationship with various organisms.
Cyanobacteria generated a large amount of oxygen. While oxygen is a highly toxic substance for living organisms, energy can be efficiently extracted by using oxygen. In principle, this process is to rotate only inversely the photosynthesis circuit (catalyzes reverse reaction). Aerobic bacteria performing oxygen respiration also evolved. They were possibly cyanobacteria that lost photosynthetic ability or bacteria coexisting with cyanobacteria.
After the major accident of 2.7 billion years ago, the area of the shallow sea also increased during lands were gathered. The attack of energetic particles from space was also prevented by the geomagnetic umbrella. Environmental conditions were developed for photosynthesis bacteria that had progressed to near the sea surface can prosper in full swing. Traces of the prosperity of the cyanobacteria which is photosynthetic bacteria of this time are left in sedimentary rocks as stromatolite fossils.
Cyanobacteria still live in various environments around the world. Cyanobacteria, like ordinary plants, have chlorophyll, which diffuses in the cell without being packed within the chloroplast. Some species live alone, but most of cyanobacteria form colonies and filaments. Cyanobacteria releases greasy glycocalix and sticks sand grains etc. in the sea. Cyanobacteria cells divide on the surface of the accumulated sand and increase the number. And they put sand grains on top of them. Thus, the sand grains accumulated over a long period of time which reflects the seasons and climate change. Thus stromatolites have a streak pattern as annual rings.
On the outermost side of the stromatolite is a membrane of cyanobacteria, and another kind of bacteria settles inside it. It seems to be in symbiosis symbiotic relationship. The basic relationship has not changed for 2.7 billion years. Stromatolite attracted other bacteria to create ecosystems and provided a foundation for the evolution of eukaryotes. Stromatolite began its peak in 2 billion years ago.
Due to the prosperity of photosynthetic organisms like mainly cyanobacteria, the biomass had increased far more than ever. Furthermore, the supply of organic molecules and the route of material circulation in the ecosystem also changed. Biological production was mainly done in shallow ocean and oceanic surface layers, and the products deposited onto the ocean floor. Biopolymers of high molecular weight were supplied to the whole ocean, and the biosphere expanded not only to the oceanic surface but also to the ocean floor. In the ocean floor up to that time, only several biospheres were found around the hot water circulation system. A large amount of carbon was fixed and added to the ecosystem. This vast amount of organic matter would guarantee the evolution since then.
In the Proterozoic era, stromatolite became to be peaked in 1 billion years ago, and fell to one-fifth of its peak in the Cambrian era.
Cyanobacteria produced oxygen from carbon dioxide in water by photosynthesis. Oxygen bound with iron ions in the seawater and precipitated as iron oxide. The banded iron formation layer that human beings use today as the major iron source deposited in this way 2.6 to 1.8 billion years ago. Oxygen concentration in the atmosphere increased to the level of about 1% from 2.5 billion to 500 million years ago. As oxygen was constantly supplied, organisms breathing oxygen evolved.
Oxygen is poisonous to living things because of its strong oxidizing action. Reactive oxygens, which are generated by decomposition of oxygen molecules by ultraviolet rays or so, reacts chemically with every molecule to destroy them, such as ones constituting the cell. Living organisms developed enzymes resistant to oxygen, such as super oxide dismutase (SOD), catalase, peroxidase, etc., and acquired tolerance to oxygen by equipping these enzymes in the body.
As the living organisms obtained resistance to oxygen, then they could utilize oxygen. They created a respiration system to synthesize ATP, that is, they could produce an energy molecule. Aerobic respiration using oxygen can produce energy for about 19 times efficiency of anaerobic respiration (fermentation). Thus, in aerobic conditions, living organisms breathing oxygen became a mainstream, supporting appearance and evolution of advanced organisms.
Oxygenation of the Earth's atmosphere is thought to have progressed in two stages, near the beginning and the end of the Proterozoic (about 2.5 billion years ago and 550 million years ago). However, it is not well understood that the ocean oxidation state in this stage and the time when oxygenation took place in the deep ocean.
This is my speculation that oxygen generated by photosynthesis may have oxidized metal ions in the sea and precipitated them as minerals. It is estimated that the Proterozoic sea salinity is five times higher than it is today. The salinity of seawater gradually decreased from 1 billion years ago, and reached the same value as it is today 600 million years ago. There is also a theory that the decrease in salt concentration in seawater is due to the increase in land area and sequestration on the continent as rock salt.
Unicellular organisms are constantly exposed to the outside world. In even single cell, sensors were evolved to know the state of the outside world, for surviving in the harsh environment. First is the water temperature which is a physical stimulus. Cells born in a high temperature environment could not survive at low temperature. Next is a light sensor. Plants that feel light to favor photosynthesis were advantageous for survival. As a chemical signal, pH, concentration of various substances and ions. It senses as food and also senses substances produced by fellows and other microorganisms.
The sensor of bacteria is called a two component system and consists of two components, a receptor protein (detector) and a regulatory protein (output device). E. coli has 26 receptor proteins and 36 control proteins (includes estimates).
It is the protein that constitutes the receptor and sensor. The protein is consisted with 20 kinds of amino acids linearly linked, and the type and order are encoded as genetic information. Protein molecules are sterically folded according to the properties of amino acids and adopt a specific structure in aqueous solution. If the protein comes into contact with other molecules, binding occurs and if it matches the moieties of amino acids at that site, the binding is further strengthened and causes structural changes of the protein (allosteric effect). As a result, the protein is activated. For example, binding to specific low molecules is strengthened, exerts enzyme activity, and interaction with other proteins is created. If binding remains at a low level the protein will not be activated. Proteins interact only with specific partners.
The receptor protein bound to the target substance in the outside causes its structural change and phosphorylates the regulatory protein. Phosphorylation is enzymatic activity. The regulatory protein is usually a phosphorylated protein, which phosphorylates several proteins in the cell and informs other proteins in the cell of the presence of the external substance. With this repetition, the cells activate the sleeping genes, activate the respiratory reaction, produce energy, and enter the dormancy regime as spores if necessary. In some cases commit suicide (apoptosis). If it is a eukaryotic cells, it causes to activate phagocytosis, change membrane transport, and change the delivery destination of the protein. These activities change the whole cell to respond to changes. If the change in the external world is important for survival, cells change dramatically.
When the organic molecules and oxygen were stably supplied by photosynthesis, it seems that the living world has changed largely in its structure. One of them is diversification through symbiosis.
It is thought that archaebacteria swallowed aerobic bacteria and cyanobacteria and began cohabiting, then changed into the organelles, mitochondria and chloroplasts, respectively, enveloped by double membranes (Maggius’s intracellular symbiosis theory). Current eukaryotic cells are not simple symbiosis, the entire genome is a hybrid of genes from archaebacteria and genes from eubacteria. When roughly divided, the information gene group that translates DNA information into protein is derived from archaebacteria and the other functional gene group is derived from eubacteria. On the other hand, ribosomal RNA sequences are divided into eukaryotes, eubacteria and archaebacteria. Estimation by the evolutionary clock of the ribosome gene, eukaryotic organisms were born about 1.5 billion years ago.
Bacteria have been found in rocks under the sea floor and in groundwater in the deep ground. Such bacteria that live in environments that are largely free of organic molecules are believed to have grown and divided over hundreds to thousands of years. The strata may have formed tens of millions of years ago, and these bacteria are even estimated to account for 70% of the earth's bacteria. Since these bacteria cannot be artificially cultured, metagenomic analysis has been performed.
Lokiarchaeota, which was first discovered in 2010 in the mud on the seabed of Greenland, was classified as an archaea and named Asgard as the archaeal phylum. Lokiarchaeota has several genes that are similar to those found only in eukaryotes. For example, actin, which is a major protein in skeletal muscle. Some proteins involved in the secretion of proteins and substances. The archaeal candidate that swallowed eubacteria is considered to be Lokiarchaeota. Eukaryotes are located on archaeal branches (eocyte theory).
Bacterial evolutionary clocks become a group at some point, reflecting crosses each other. Prokaryotic DNA is considered to be free to cross when the cells are fused because the DNA is naked inside the cell. Therefore, the phylogenic tree becomes complexly merged or ring-shaped, so that the origin of life cannot be converged into one genome.
Throughout the history of the Earth, the volcanic activity was the highest around 2.7 billion years ago and 1.9 billion years ago. Volcanic activity produced a large amount of magma and became the foundation of the continent. At about 2.7 billion years ago, the mantle convections of the outside and inside merged. Also, about 2.0 billion years ago, the temperature of the Earth's crust and the outside layer of mantle declined, then water sank along with the oceanic crust. As a result, massive amounts of granitic rocks were made on the subduction zone. A homogeneous and hard graniteous continental land mass was formed in a short period. The 1.9 billion years ago a supercontinent was formed for the first time. Continental growth can be explained as the heat release mechanism from inside the Earth.
The continental fragment stabilized before the Cambrian period is called craton. The oldest ones among cratons have existed since 1.8 billion years ago. It is just the age when the first supercontinent was formed. When the supercontinent is formed, small lumps, derived from the volcanoes along the plate subduction zone that had been formed over from about 4 to 2 billion years ago, were considered to be collected and stacked up.
The Laurenia (Nuna) continent was formed for the first time before 1.9 billion years ago, then Rodinia, Gondwana, and Pangea supercontinent were made one billion years ago, 550 million years ago and 300 million years ago, respectively. This cycle is called the Wilson cycle, during which the number of continents was changed, sea level was varied, glaciers are developed, and mass extinction of living organisms had occurred. All of these caused the evolution of living things.
Laurentia continent would be reconstituted by connecting traces of the mountains (now plains). It formed from North America, Greenland and Northern Europe. Other land areas in that era were southern Siberia, East Asia, Antarctica, Australia, Africa, South America, India, and small areas around the Black Sea and the Caspian Sea (all are fragments).
The largest meteorite crater in Earth's history is the Vredefort Collision Structure (South Africa, 300 km diameter) about 2 billion years ago, and follows by the Sudbury Collision Structure, 1.85 billion years ago (Canada, 250 km diameter). These Meteor Craters can be preserved because the continental mass was formed for the first time in Proterozoic era. On the other hand, the Chicxulub crater that destroyed dinosaurs is 180 km in diameter.
The Rodinia continent is thought to form by gathering most of continental lumps, mainly on the south side of the equator about 1.1 billion years ago. The thickness of the oceanic crust is estimated over 15 km in the past fbefore 1.5 billion years ago. whereas it has become thin as 5 km after 1.5 billion years. Old oceanic crust has been wiped out by the formation of the Rodinia supercontinent. As a result, the speed of the plate increased. The Glenville orogenic movement occurred due to the collision of the continents to form the Rodinia. The continent started to divide 750 million years ago.
As the temperature of the Earth cooled down, it is thought that the top of the hot plume had gradually moved deeper under the crust. Currently it works only at the level deeper than 670 km. This depth is also the depth of Megalith is made. The depth should have been shallower in the more past. While the Earth was hot, the seawater entered into the plate as hydrous mineral was separated by heat and returned to the ground. However, as the Earth cooled down, water ceased to be separated and it remained in the mantle as a hydrous mineral. This is called injection of seawater into the mantle. It started 1000 to 600 million years ago, and sea water has decreased to two-thirds so far. Land increased from 5% to 30%. With the advent of the Gondwana supercontinent, a huge continent emerged for the first time on Earth.
The plate contains sea water while it is formed and moves to the subduction zone. After being sunk into the mantle, water is separated by heat and pressure. However, with the turning point in the range of 1.0 to 600 million years ago, the water was not completely separated from the plate. In other words, it can be said that the earth was getting colder. As a result, sea water was injected into the mantle, sea water decreased, and the area of the land slowly increased.
Rivers developed and flowed through the land. Sediments were transported to the sea by rivers and became sedimentary rocks. Organic matter produced by living organisms at the bottom of the ocean was trapped in the sedimentary rocks and was not oxidized. Oxygen concentration in the atmosphere increased around 6 to 5 million years ago. As oxygen concentration increased, the living organisms can obtain energy efficiently by aerobic respiration, so the organisms can maintain a larger body. , Anaerobic organisms, found everywhere on the earth until then, have been driven to environments where there is not much oxygen, such as in the soil.
As the supercontinent Rodinia was formed, the rocks weathered and were brought to the sea. Alkali metal ions contained in rocks were dissolved to the seawater, where carbon dioxide was absorbed to neutralize these ions. Furthermore, in the split phase of the supercontinent, a shallow sea spread out between them and cyanobacteria propagated there, photosynthesis lowered the concentration of carbon dioxide in the atmosphere. As the concentration of carbon dioxide in atmosphere decreased, atmospheric pressure also decreased. Carbon dioxide in the atmosphere has been rapidly consumed as the continent has grown rapidly since the 2.7 billion years ago, and the global environment has evolved into an environment similar to the present condition for about a billion years ago.
The sun is darker as it goes back to the past, and the average temperature of the Earth about 2 billion years ago was assumed below zero. Then the Earth should have been frozen globally before 2 billion years ago. However, there are evidences in sedimentary rocks which shows not to be frozen. We call this ‘faint young sun paradox’. Carbon dioxide is a powerful candidate as an atmospheric component explaining the paradox. The Earth, which lost the greenhouse effect of carbon dioxide, has experienced two global freezing since a billion years ago.
There are mainly two evidences of freezing at the equatorial zone. One is diamitite. When glaciers scrape and transport the bedrock, sediments called diamitites are formed in which gravel, sand and mud coexist. At this time, the gravel remains after the glacier has been scraped off. The second one is dropstone. Mud and fine sand at the bottom of the sea deposit offshore. If there is big gravel stuck there, we call it dropstone. Dropstone is thought to have been brought by the iceberg.
If the Earth's surface is completely covered with ice, the most living organisms are thought to have extinct. However, it is known that cyanobacteria survive even on the surface of glaciers, making stromatolite - like structures. It is known that insects and bacteria can live even on ice. Also, at the active place of volcanic activity, where would have been not completely frozen, some living organisms could survive. The last snowball earth is said to be from 800 to 600 million years ago. At this time multicellular organisms were considered to be born and have evolved. A basic group of genes necessary for constructing multicellular organisms is also born at this time (the root of the working genes is here in evolutional phylogeny tree).
It is estimated that the temperature has reached -50 ° C during a snowball Earth of 800 million years ago. However, due to balance with crustal heat, the seawater at the bottom of the ocean did not freeze. While the speed of photosynthesis is decreasing during global freezing, on the other hand, supply of carbon dioxide was made by volcanic activity continuously, greenhouse gases are accumulated and the temperature started to rise. It takes at least 4 million years to accumulate in the atmosphere the amount of carbon dioxide necessary to melt the entire ice of the Earth. Once rising, the albedo effect decreases, so further deicing progresses. Rapid warming caused storms and floods. After a while, the high temperature period continued for a while.
Reductive substances are supplied from the seabed hydrothermal vent, so oxygen dissolved in the seawater is considered to be exhausted during snowball Earth. Under such an oxygen-poor environment, divalent iron ions supplied from the seabed hydrothermal vent can be dissolved. A large amount of iron ions accumulated in the seawater at deep ocean over a long period of snowball Earth to the onset of ice melting.
Grypania appeared 2.1 billion years ago. It was found in Banded Iron Formation (BIF) in the United States. It is considered to be a eukaryote because it is a large alga with a size of about a few millimeters and cannot be this size in prokaryotes.
Algae are regarded as primitive plants. It is classified into 10 eukaryotic plant divisions, which are greatly different in cell structure and function, and cyanobacteria which are prokaryotic algae. It is thought that algae could be formed through multiple intracellular symbiosis of organisms of different origins. Chloroplasts are thought to be cyanobacteria, which have changed by intracellular symbiosis. The chloroplast looks like a wrapped Cyanobacteria with the membrane of the maternal cell. That is, the chloroplast has two cell membranes. This is the primary intracellular symbiosis. Green plants, red seaweed plants and gray plants commonly found in three primary phylum are symbiotic form in the primary intracellular symbiosis, which are the major of the current plant world.
There are algae with three or more chloroplast envelopes. These algae are born from the secondary intracelluar simbiotic plants. It is thought that the first intracellular symbiotic plants have entered other cells and cohabited. Algae that acquired chloroplasts by secondary intracellular symbiosis are regarded as the sixth field independent of the plant kingdom, the chromista world. As a side note, the remaining five are the Monela world (Prokaryote), Protozoic world, Plant world, Fungus world, Animal kingdom.
Cellular organs have evolved that maintain and utilize diverse membranes. For example, a space wrapped by membranes is utilized to create a concentration gradient by enzyme reaction in the membrane. Proteins developed that convert the potential energy through concentration gradient into chemical energy, ATP. In current organisms, most of the ATP is supplied by a concentration gradient (chemical osmotic theory). Typical examples of intracellular organisms that efficiently produce concentration gradients are the mitochondria responsible for respiration and chloroplasts responsible for photosynthesis. Also, there are lysosomes and phagosomes that trap substances that become unnecessary in cells and substances taken from extracellularly, respectively, into membrane bags (vesicles) and digest them. Proteins that are secreted outside the cell are synthesized in the endoplasmic reticulum and processed and modified through the Golgi apparatus, all of which proceed by providing a special reaction field by vesicles.
Eukaryotic cells have not only increased volume, but also evolved important intracellular movement organs, such as cell division machinery, in addition to membranous organs. The mechanism that made the primitive eukaryote has created more complicated intracellular symbiotic organisms. Furthermore, it is possible that more combination was made, and it seems that many gigantic cells may have appeared that are not currently present. It is thought that its driving force was efficient energy production and substance production realized by division of intracellular labor and specialization. Also, energy-efficient oxygen respiration will support the birth and evolution of advanced organisms.
Among parasitic microorganisms, there are creatures living by getting into cells. Shigella and other bacteria attach to the intestinal cells, inject proteins into the cells to acceptable the bacteria, and let them take in. The intracellular bacteria hide from the digestive system and intestinal immune system, and can grow in small intestine cells.
Schizon is one of unicellular algae with the most primitive structure among plants. It is a kind of red algae, it lives even in a strongly acidic, high temperature environment (hot spring). Schizon has every intracellular organs of eukaryotic organism, but there is only one. It is the simplest structure as a plant. Therefore, it is noticed as an ancestor of plants. The cell nucleus contains 20 chromosomes and the genome size is 16,520,305 base pairs. There are 5,531 genes, almost the same number as yeast and malaria parasites which are eukaryotes of single cells whose genome has already been determined. Its mitochondrion has a genome of 32,211 base pairs, and chloroplast has of 149,987 base pairs. Chloroplast genome size was minimal in plants.
Malaria parasite is a unicellular eukaryotic cell organism. When infected in living organisms, malaria first grows in hepatocyte then lurks in erythrocytes. Malaria produces parasitic membranes in the red blood cells and is enveloped in the membranes. The malaria parasite secretes various proteins, disintegrates parasitic membranes, and sends proteins to the whole erythrocytes. The processed erythrocyte escapes to the host's immune function. Molecular mechanisms of malaria that enter and control the red blood cell are now a major research field. The mechanism would have been evolved over several hundred million years before multicellular organisms were appeared on the earth.
Cells started with intracellular parasitism, then their forms progressed complicated and diversified. Their abilities have been refined. Microorganisms have emerged that live in the cells while maintaining independence. For example, Shigella and the like bacteria attach to the intestinal cells, inject the protein into the cells, and make themselves take in. It grows in cells hiding from host digestive system and immune system. The malaria parasite is hidden in red blood cells, wrapped in a parasitic membrane. The processed erythrocyte escapes to the host's immune function. The basis of the molecular mechanism of entering and controlling the cells may have been evolved over several hundred million years before multicellular organisms were formed.
A eukaryotic cell was born and the mechanism of sexual reproduction was arranged.
The gene replication device is not 100% perfect. Replicating devices of the current living organisms make mistakes with a probability of about 1 / 10,000,000. Mutation accumulates gradually as it duplicates and divides into two. Eventually, the organism dies when a fatal mutation occurs. Even more deadly, before the ozone layer was formed, a large amount of ultraviolet rays were falling on the Earth 600 million years ago, and the ground and the sea surface were a death world for organisms where genes made of nucleic acids were destroyed away.
Bacteria just born on the Earth developed a mechanism of exchange their genes each other to repair genes broken by ultraviolet rays. Since the birth, bacteria formed aggregates and lived together, which has become a driving force to have the recombination mechanism. Conversely, having a gene exchange system was essential for stabilizing and perpetuating species. It also became a defense mechanism against accidental mutations.
When the environment got worse, the ability to exchange genes was demonstrated to be highly active. Bacteria gathered together, made the dead friends food, sometimes cannibalized and survived a difficult environment. It is assumed that they provide their genes to fellows to survive. It is also assumed that intracellular symbiosis has been born in this process.
When bacteria started to live as individuals, the mechanism of gene exchange was established as a conjugation. Bacterial cells recognize each other, bind, and form a tube between each cell to convey the DNAs. After that, the genome of one bacterium is duplicated and sent to the other. Transferred DNA is recombined mainly with homologous parts and exchanged. At this time, it is irrelevant whether the homologous part is broken. The gene set of genes necessary for conjugation is carried by the carrier genes called plasmids. Plasmids are maintained in the bacterial population by carrying genes useful for the survival of bacteria such as antibiotic resistance and phage resistance.
When a nucleus, which is an intracellular organ that stores genes, was born, the whole gene exchange has been carried out regularly with the nucleus as a unit. It is the birth of eukaryotes. First, two sets of genes necessary for life (genome) were prepared. In fungi (eukaryotic cells, not eubacteria), one genome is usual (haploid) when proliferating by cell division. Only when they perform sexual reproduction, they stick (join) and exchange a set of genes, that is, exchange of one of the genomes. Two sets of genomes in the participant cells are randomly exchanged with homologous portions of genetic information. The new genomes are separated into two spores, which will be the next generation. Various forms of exchanging genomes may have been tried in ancient era.
Sexual reproduction, one method of proliferation of eukaryotic cells, consists of two processes: conjugation (fertilization) and meiosis. In conjugation, two haploid cells can be fused together not only to the cell membrane and cytoplasm but also to the nucleus into diploid cells. In meiosis, four haploid cells are generated from one diploid cell through homologous chromosome pairing and two steps of mitosis after the genome replicates to 4 sets in a cell. It is estimated that the sexual reproduction mechanism was established about 1 billion years ago.
Even in sexual reproduction of the simplest fungus, the mechanism is complicated. Many proteins collaborate to do this process. Replication of genes uses an existing mechanism, but even if genes are duplicated they are not divided into daughter cells, so new control functions are necessary other than mitosis. Also, the new control function must be programmed to only activate during sexual reproduction. Until the sexual reproduction mechanism is completed, many evolutionary genes were born, and their invocation program would have been reworked. The advanced equipment of modern organisms is the result of continuous improvement of the mechanism. The body of higher organisms is based on diploid cells and produces haploid cells (sperms and eggs) only when sexually reproducing.
At the same time, sexual reproduction accelerated the evolution by periodically exchanging genes. Especially when the genome size becomes large, gene exchange by sexual reproduction is effective.
It is difficult to describe 4-dimensionally of changes in living organisms including time such as development, growth and aging. Large multicellular organisms are too complex, and various researches have been done to describe everything from the nucleotide sequence of genes, which is one-dimensional information, to a stereoscopic three-dimensional structure (From 1D to 3D) in terms of molecules. In principle, lines are made by points side by side, a surface is made by lines, a surface is bent to become three-dimensional structure. Also, the line forms a helix to form three dimensional structure. Whether it is a polypeptide chain or a structure formed by a protein, the same principle is used for the organization of tissues and organs by cells. And genome has evolved little by little through mutation for these changes and has been selected naturally.
Specific genes in the multicellular organism such as genes related to nerve or cell adhesion can be found in the monocellular protozoan Monosiga ovata. Genes necessary for becoming multicellular organisms were already prepared for single cell organism era. When multicellular organisms become involved, the receptor protein for detection of the outside world of the cells and the regulatory proteins linked thereto are remarkably increased. Genes related to cell differentiation such as homeobox gene family diversified 800 to 600 million years ago. The homeobox gene is a regulatory gene that controls morphogenesis in the process of multicellular animal development. It seems that the homeobox gene family, responsible for the body plan and the interaction such as cell adhesion, and related genes, responsible for intercellular information, diversified through gene duplication, and enhanced the function of the organism.
When harmful genetic mutation occurs, the protein is incorrectly folded. As a countermeasure there is a group of heat shock proteins. The heat shock protein plays roles that correct the denatured protein to the correct shape and must have evolved as a protein group corresponding to the sudden temperature change. Organisms can accumulate many genetic diversity depending on the ability of heat shock proteins. This hypothesis was demonstrated by experiments in Drosophila. Drosophila accumulates many gene mutations over the generations, the amount of which depends on the ability of heat shock proteins. When stress is applied such as change of survival environment, ability of heat shock protein cannot catch up, accumulated mutation appears as a phenotype at once. If this phenomenon responds well to environmental changes, is not it a great evolution of living things?
MicroRNA, a small inhibitory RNA molecule discovered in C. elegans in 1993, is widely present in animals with a complex organization. It was thought that genetic information was translated into protein via RNA and had a function, but microRNA is involved in gene regulation as a molecule. With the advent of microRNA, in addition to genes that function as proteins, genes that function as regulatory RNA have been added. Sequencing of total RNA in primitive metazoan phyla and unicellular animal Dinoflagellates revealed that regulatory microRNA pathways would have been born very early in metazoan evolution (when multicellular organisms emerged).
The function of a neuron is to generate an electrical pulse signal for a stimulus, which is transmitted end to end in the cell. Neurons were thought to exist only in multicellular organisms, but similar functional molecules were found in unicellular Chlamydomonas. It is channelrhodopsin. It is a protein that responds to light stimuli. In addition, Chlamydomonas has genes that do not form synapses but are necessary for synapse formation, receptors for neurotransmitters, cell adhesion molecules and lining proteins of the plasma membrane. Chlamydomonas is believed to have appeared in the living world 1 billion years ago. Chlamydomonas, which has flagella and has the function of generating nerve pulses, is reminiscent of hair cell sensors possessed by multicellular organisms. In channel rhodopsin, rhodopsin in which opsin protein and retinal are bound also acts as an ion channel to form a light-gated ion channel. Since it is possible to control nerve activity with a laser in animals into which channelrhodopsin is introduced, it has been applied as a brain function analysis technology (optogenetics technology).
The evolution of unicellular organisms to multicellular organisms seems to have taken place over and over again in the plant family alone. The multicellularization occurred at least in brown algae, yellow-green algae, and so on. In other words, multicellular plants have evolved in multiple lines.On the other hand in animals, multicellularization seems to occur only in a single strain. The immediate ancestors of multicellular animals are thought to be unicellular organisms called the Choanoflagellates. It evolved from the Choanoflagellates through the sponges to many multicellular animals.
In lower multicellular organisms, where the cells are clustered together, there is a high degree of cell independence. All parts of their body have the ability to regenerate the whole body. Today's plants have similar regeneration capabilities. Before the development of multicellular organisms with differentiated functions, the substance that wraps the cells in a group must have evolved as the basis for the cells to gather together. In modern life, it is an intercellular matrix, a complex polymer composed of proteins and polysaccharides.
However, multicellularization is not always an aggregate of one type of cell. Given the history of symbiosis those days, it is highly possible that many kinds of unicellular organisms formed an aggregate. By creating aggregates, cells could increase the probability of survival in harsh environments. When there is no food, some of the cells that make up the aggregate are sacrificed to help the rest of the cells, maintaining the organism as a whole. Gene sharing had progressed among the various types of organisms that have formed aggregates, and changed from aggregates of cells with diverse genomes to aggregates of cells with one type of genome. Some cells differentiated as germ cells and developed a reproductive system that exchanges genes.
In order for cells with a uniform genome to assemble, it is necessary to strictly distinguish cells having own genome from cells having other genomes. When it was a single cell, the cell membrane was a distinction between self and others. It is the receptor on the cell surface that distinguishes self from others (non-self). Receptors on cell membrane capable of identifying self on a large number of individual cells has been prepared and evolved. At the same time receptors that recognize other cells developed to recognize food and enemies.
An aggregate of cells that share the same genome eventually develops into a cluster of cells that share various functions. An example is a germ cell. A germ cell is a cell to be preserved forever to convey all functions as genes to the next generation. Then, all cells of the body with the necessary functions are differentiated from the germ cells. By making germ cells resistant to environmental changes, organisms have new survival strategies.
Estimating from the gene evolution clock, multicellularization began 900 million years ago. At first, marine sponges and other animals diverged. After that, the diploblastic animals such as jellyfish, sea anemone and hydra were branched from the marine sponges, and the triploblastic animals, a group of major animals now, branched from the diploblastic animals.
These organisms are not simply aggregates of cells, but are formed from differentiated (have a role) cells. Roughly speaking, the jellyfish and sea anemone are of a ball with a follow. It splits into outer cells (ectoderm) and inner cells that form the digestive system (endoderm) (two germ layers). In the three germ layers, there are cells between the outer and the inner cell layer, called mesoderm. When considering the human body as a cylinder, the outer side, that is, the skin is the ectoderm, the inside of the cylinder, that is, the gastrointestinal tract is the endoderm, while the muscle and the bone are mesoderm.
On the outside of multicellular organisms a membrane of cells called the epithelium was created. It is necessary to have the ability of cells to strongly adhere to each other in order to protect the organism's body from impact. At the boundary with the outside world is called epidermis (skin). However, mucosal epithelium was formed on the surface followed inside the body (inner side of digestive tract etc.) due to material exchange.
The parts (organs) of the body of an organism are wrapped in a cell sheet called epithelium as well. In the stomach (abdominal cavity), it is called serosa and consists of mesothelial cell epithelium. By wrapping with the epithelium, it created a specialized space. Cells can be placed in epithelial bags, and various functions such as liver, kidney and reproductive organs can be formed as independent organs. Organs are connected with blood vessels and nerves. The environment of the body has become possible to keep in a certain condition, to store nutrients, for internal organs to have specialized functions, and to make their own exercise.
Collagen protein is used to physically strengthen membrane of epithelial cells. The amino acid composition of collagen is biased consisting of simple amino acids, 1/3 of glycine, 21% of proline and its derivative, 11% of alanine. It has a simple backbone consisting of repeating 3 amino acids with a glycine and two other amino acids.
It is thought that collagen was first born on the Earth after the snowball Earth age in the late Proterozoic period (600 - 800 million years ago). Unicellular organisms that produced collagen were used it for cell-to-cell adhesion, promoting multicellularization. Collagen is, so to speak, a clothing, a cradle, a structure to call a room. Collagen is the major protein that constitutes the connective tissue of animals, and in mammals it is the most abundant protein that makes up 25% of the total protein content. In other words, in the animal body cells are wrapped in a collagen cocoon.
About 680 million years ago, the triploblastic animals were divided into groups of deuterostome animals and protostome animals. A group of protostome animals was divided into a group of Ecdysozoa including arthropods and round worms and a group of Lophotrochozoa including molluscs and Plathelminthes. From deuterostome animals, sea urchin and sea squirts appeared. These multicellular organisms are difficult to become fossils, so there is no geological evidence left.
It is a time of the snowball Earth occurred 800 to 600 million years ago. At the same time, the South Pacific Super Plume began to rise and the Rodinia supercontinent began to divide. 600 million years ago, when thick glaciers melted covering the entire Earth, oxygen concentration in atmosphere began to increase sharply. The sea between the dividing continents was warm. It is thought that the evolution of life using oxygen had started repidly, that is, the enlargement of their bodies. By the time around 550 million years ago, the next super continent Gondwana was formed and began to divide soon. As multicellular organisms in those days, Ediacaran biota is left as a fossil
The Ediacaran biota was found on Newfoundland Island in Canada. The animals with only a soft body were preserved as a fossil because a volcanic ash buried the bodies in a short time by a volcanic eruption. In the Ediacaran biota, the big one reaches as much as 1 meter in diameter, but it is a thin flat plate, and it does not seem to actively move around. They are symmetric or rotationally symmetric. Were they slowly moving with symbiotic photosynthetic bacteria on their back?
At that time, many stromatolites were in the shallow sea, and a mat of blue-green algae (biomat: there was slimy texture with rock and microbial membranes covering the ground) attached on the bottom of the ocean. The Ediacaran biota declined at the beginning of the Cambrian age of 543 million years ago. The cause of the decline is thought to be related to the explosive volcanic activity in the early stage of continental division, or because the Burgess shale type fauna animals that appeared in the early period of Cambrian era had been exhausted them.
A large amount of fossils are discovered from the early Cambrian period (543 million to 490 million years ago). It seems that organisms have appeared suddenly, so call it Cambrian explosion. Fossils around this time contain Burgess animals, famous for strange large organisms such as Anomalocalis and Opabinia. They are named after the Burgess shale where fossils were stored. As the soft part of the body remained completely, we were able to investigate the structure and function of the animal's body in detail. Trilobites, well known fossils, also prospered in those days.
Many direct ancestors of the present living organisms also appeared in this period. Arthropods (spiders, scorpions, horseshoe crabs and trilobites), chordates (with the notochord of the backbone) and vertebrates. Chordates animals, which are prototypes of living organisms with backbone that became our ancestors, are only a few centimeters in length and belong to primitive fish, such as jawless fish.
From the evidence of fossils, the appearance of Burgess fauna is sudden. The rapid evolution is the result of accumulation of previous genetic mutations. Crustacean animals and arthropods are known to grow as small plankton during larval period. In the earlier Proterozoic era when fossils are not found, it is thought that living organisms overcame the cold season as a small plankton. There are various opinions on opportunities to achieve large size and opportunities to build armor, but I want to mention that the oxygen concentration in sea water has increased to a certain concentration and the global warming.
Predators can get nutrition and energy quickly by eating other creatures. It is predictable that the predators had advanced eyes and had high motile performance. They would have used aerobic respiration for their movement. Also, they developed a integrating nerve tissues to control their muscles based on the information of the sensor. The neural circuit as a system is thought to appear first as the scattered nervous system of hydra and jellyfish. It is necessary for big body to have a mechanism to efficiently carry oxygen and nutrients to whole body. On the other hand, many animals have developed mineral exoskeletons when the emergence of large predators. It is thought that the relationship of food chain was born in the period of Cambrian explosion. The relationship of the eat and eaten added arms race to evolution process.
The Pax-6 is the gene that gives the first command to make eyes, that is, the master control gene. The most primitive organism having the Pax-6 gene is planaria. The organism created an apparatus with dent on the surface of the body and placing photoreceptor cells on its bottom to know the direction of the light source. Planaria belongs to Order tricladdida in Class Turbellaria in the Platyhelminthes and is the branch point between Ecdysozoa and Lophotrochozoa. The flat body reminds us of the Ediacara biota. As a result of the evolution, the dent has a lens, and the photoreceptor cell forms a sheet called the retina, which projects the external world. The apparatus became an eye to recognize the world.
Trilobites are thought to have taken up mud with a lot of limbs and were feeding nutrients together with mud. There are a lot of characteristic drilling traces (living traces) left. Biomat played the role of canvas for the living traces. Samples of late Cambrian or early Ordovician period (about 500 million years ago) have walking traces of animals left on sediments close to the ocean. It was a large arthropod with at least 4 pairs of walking limbs, probably of a eurypterid, and the trace of the tail could be discerned. While digging under the biomat covering the surface of the ocean floor, some animals were eating humus of biomat, and tunnels are left as trace fossils.
A large amount of phosphate was accumulated in the Cambrian period, and it became phosphate ore. After that, speaking of phosphate ore was bio-origin. A typical example is guano, which is feces of birds.
The Gondwana continent passed Antarctica from Ordovician to Devonian period. Most of the lands at those periods were in the southern hemisphere. The protrusion then weathering of the mountains of the Appalachian range affected the chemical composition of the atmosphere and the ocean. Particularly, carbon dioxide was immobilized as rocks.
The Cambrian creatures mostly died out 500 million years ago and Ordovician creatures emerged. In a word, it was the emergence of the sea of fertility. The relationship of living things became complicated, and landscapes like the current coral reef were created. Octopus, squid, shellfish and other marine produces were born, which the Japanese likes. As the Cambrian creatures suddenly appeared as a fossil, it was named a large explosion of evolution with a meaning of surprise. The Ordovician creatures brought the diversification of living organisms far beyond the Cambrian period.
A representative organ of the organism born in the Ordovician period is a calcareous shell. Stromatoporoid, corals, Brachiopoda (lamp shells), snails, sea lily and nautilus (ancestors having shell of octopus and squid) appeared. The shells are thought to be as equipment to protect them. The creatures in the ocean thrived which can protect themselves from carnivores.
In the Paleozoic era, Stromatoporoid that creates reefs was prosperous. After the Paleozoic era, fixation of carbon dioxide by living things was done on a large scale in the sea. Besides coral, there is plankton with shell made from calcium carbonate in the ocean. Creatures may have contributed to the reduction of carbon dioxide. The Ordovician period was relatively cold.
The evolution of chordates to vertebrates, that is, the birth of fish, occurred in the shallow sea of the late Cambrian. The first vertebrates to appear are jawless fish. Among the jawless fish, there appeared ones that protected the body by adhering calcium phosphate crystals to the body surface, which was advantageous for survival. It was the crustaceans in the Ordovician that completed the armor of calcium phosphate as a carapace. The ancestors of this species of vertebrates do not live today. The existing round-mouthed animals lose their carapace and become naked. During the process of evolution, it changed from the exoskeleton called the carapace to the endoskeleton.
Collagen fibers are proteins of the outer coat that were born when organisms became multicellular. Vertebrate bones are built in cartilage. The primordial vertebrate body surface would have been covered with thick collagen fibers. The first bone was calcium phosphate secreted into the collagen fiber of the skin and covered the body like an armor. Currently the skull bone has its remnants. The carapace is a small piece like a tooth, covering the body like scales.
In the vertebrate animals that lost the exoskeleton, the endoskeleton developed. Bones that protect nerve tissue like spine. Bones that protect visceral tissues like ribs. And limb bones for exercise. The turtle shell is a rib. Teeth were arisen from the skull as ones of the exoskeleton. Vertebrate bodies are also divided into somites like insects, and vertebrae are the basic unit. You can see the effects of somites on the development of bones and internal organs in the fetus.
In the Ordovician period, vertebrate was divided into a jawless vertebrate, such as lampreys or hagfishes, and Gnathostomata which has a jaw. Later, in the vertebrate lineage, Gnathostomata appeared in the sea one after another from Devonian to Silurian period. Quadrupeds evolved from Gnathostomata about 400 million years ago in the Devonian period.
The genes RAG1 and RAG2 catalyze a genetic recombination of V (D) J genes of antigen receptors such as immunoglobulin, and realize diversity of acquired immunity. These genes are thought to encode a transposase derived from a mobile genetic element inserted into the vertebrate genome at 450 million years ago. Therefore the establishment of acquired immunity is around Ordovician period.
The world of various creatures in the ocean produced in the Ordovician period has been partially extinct several times, but lasted about 250 million years until the Permian era. This period is called Paleozoic era. Every time on extinction of a comparatively large extinction occurs, "period" changes. The Gondwana supercontinent reached the Antarctica and became cold, so the glacial period and interglacial period began to occur alternately. There is extinction of living creatures, about 57% of the genus has been extinct. Then the Silurian period started. In the Silurian period, the plants advanced onto the land.
During the Caledonian orogenic movement, the Iapetus Ocean became a land in the Silurian period. In the Silurian period, plants expanded to the land, arthropods followed them. Furthermore, fossils of plants with the vascular bundles have been found at the end of the Silurian period.
When enough oxygen was accumulated in the atmosphere, an ozone layer was formed. The ozone layer acts as a barrier to cut off harmful ultraviolet rays, allowing organisms to move to the land. It is about 420 million years ago. Compared with in the sea, there are still a lot of ultraviolet rays lethal to life on land, and furthermore, a structure to support the body and mechanism for preventing drying are necessary because there is no water nor buoyancy. On the other hand, there was also a favorable condition that the oxygen concentration was much higher than in the sea, and there were no competing organisms. It was an attractive environment for plants in the sense that both light intensity and carbon dioxide amount are much higher than in the sea.
Lichens (mosses) appeared, followed by plenty of Pterophyta. The oldest land plant fossil is the spore and sporangia of a moss found in Oman. It is 470 million years ago (Ordovician period). The oldest fossil of the plant is Cooksonia and it was of the middle Silurian period (425 million years ago). Even though it was a Pterophytum, the leaves were yet not differentiated and it had only a stem. In order to withstand drying, plants must have stomas that allow moisture regulation. It needs a structure bundling thin tubes (plant vascular bundle) that can carry water and nutrients against gravity. The plant vascular bundle evolved more and more efficient structure, at the same time, the stem became robust.
After plants succeeded on land, animals like mites eating rotten plants advanced to the land and then insects did. The oldest insect fossil is 400 million years ago (Silurian period) discovered in Scotland. Since animals need to support the body on the land without buoyancy and to withstand drying, the arthropods were able to land easier because their body was covered with external skeletons. In order to move around on land, the external skeleton was divided by the joints, and the motile organs such as the foot were prepared to support their body.
It was the placoderms that dominated in the sea in the Devonian period. The placoderms are the first fish with a chin and had a hard armor. Fossils with placenta and umbilical cord were found in the placoderms. Early Gnathostomata seemed to have a wide ability of internal fertilization and viviparity. The origin of viviparity dates back to 360 million years ago. Modern sharks have the same mechanism.
The Devonian period is called "the age of fish", and the original form of a vertebrate was created. Early bony fish, which appeared in the Silurian period, had calcium phosphate inner skeleton, that is, a mineral reservoir, so it was able to enter the brackish water and fresh water area. Bony fish flourished in the freshwater area of the Devonian period and were the ancestors of most fish today. As rivers and lakes are under various climates, fish evolved variously, under ecologically isolated environments. They then gradually returned to the sea in the latter part of the Devonian period.
A certain bony fish equipped with lungs. The lungs were the organ bifurcated from the esophagus, and had dense capillary vessels distributed throughout the tissue. Lung fish was able to survive under drying circumstance. Lung fish is a fish called sarcopterygians located between an animal with four legs and a fish. Its arms are bound to the shoulders with fleshy fins ahead. Most of the fishes are Actinopterygian. Their radiating bone is directly attached to the shoulder.
The limbs of vertebrates arose from pectoral and ventral fins of ancient fish. A primitive fish had a fin from the back through the tail to the belly. Fish got two pairs of fins, pectoral fin and pelvic fin from there. The gene that dominates the structure of the body is the Hox gene. The expression of the Hox gene in the American paddlefish, a living fossil (> 250 million years ago), has been analyzed and its origin is under investigation. Fish and frogs have no head. Morphogenesis of the neck is also controlled by Hox gene. The neck evolved since vertebrates began to live on land.
It was supposed 380 million years ago that the sarcopterygians such as Eusthenopteron began to live on the land. It may be that the flesh fins developed to move in the water with many obstacles while pushing obstacles, which is usually seen on the land. It seems that lung respiration develops in a shallow swamp or somewhere, where fish is difficult to breathe due to turbid and stagnant water. To feed insects on land above, the head became flat, the eyes moved upwards. The eyes peek above the water surface while the body is under the water surface. Get food by jumping with flesh fin.
Fossil footprints left by terrestrial vertebrates which had four limbs were dated about 400 million years ago. It was found in the Zachelmie rock quarry in the Holy Cross Mountains in Poland. Some of the footprints are extremely good in preservation state and allow detailed examination of the form of the foot part, which is similar to Ichthyostega, a primitive tetrapod in the early stage. It is 18 million years older than the oldest fossils of tetrapod body.
The amphibian evolved from the sarcopterygians. The most primitive tetrapod is Acanthostega and Ichthyostega in the late Devonian period, and these had 8 fingers and 7 fingers, respectively, on each foot. The emergence of amphibians is the late Devonian. Although the inland area was dry, the large forest kept moderate humidity and created a cradle environment for amphibians.
Again it became globally cooling, and 35% of the genus had been extinct. Probably, the reduction of carbon dioxide caused cooling, due to weathering and formation of soil by diversification of land plants. The relatively slow extinction means global warming was also the cause of the extinction after cooling.
Here I briefly summarize history from the division of Rodinia Continent to the formation of Pangea supercontinent. During the collision of the continent, two large orogenic movements occurred, that is, the Caledonian and the Variscan orogenic movement, resulted two large mountain ranges were formed.
Around 600 million years ago, the Rodinia continent split into four continent, the Gondwana, the Siberia, the sub Laurasia (North America and Greenland), the Baltica (northern European land masses including the Baltic Shield and the land masses of West Africa around Morocco). The Gondwana continent was in the Southern Hemisphere and the other continents were in the Northern Hemisphere. The relatively shallow ocean is called the Iapetus Ocean surrounded by the Siberia, the Laurasia subcontinent, and the Baltica.
In the Ordovician period, the Iapetus Ocean was sandwiched with the Lauracia subcontinent at the West and the Baltica continent on the East. The Baltica continent approached the Lauracia subcontinent and the Iapetus Sea disappeared at the end of the Silurian. We call newly formed continent as the Euramerica continent. At the place where the Iapetus Ocean was, a large mountain range was formed from the Scandinavian mountains in Norway and Sweden, through UK and Ireland, to the Appalachian mountain range on the east coast of North America. This is called the Caledonian orogenic movement. The Caledonian orogenic movement occurred 420 to 390 million years ago (Devonian period).
The Rheic sea expanded during the Caledonian orogeny movement. The Gondwana continent located on the south side of the Euramerica Continent across the Rheic Sea, and the south side of the Gondwana continent reached the Antarctic in the Carboniferous period.
The Variscan orogenic movement occurred during the Carbonifeous period (3.5-2.9 million years ago). This orogenic movement is a subduction of the Rheic Sea under the Euramerica and Siberia continents. The collision between the Euramerica and the Gondwana continent of the west side made the Rheic Sea close in the late Carboniferous period. As a result, a large devastating mountain range from Czechoslovakia, Germany, Belgium, Northern France, to the Iberian Peninsula were formed. The eastern side of the Rheic Sea is renamed the Old Tethys Sea. The Old Tethys Sea was surrounded by the Euramerica continent and the Gondwana continent.
Finally, the Siberia continent collided with Euramerica Continent, the Lauracia continent was completed and the Ural mountain range was formed at the collision surface. The Lauracia continent and the Gondwana continent gradually approached, and the Pangaea supercontinent was made at the end of the Permian period.
Since the two major continents collided at that time, its scale of the influence was the largest in history. The formed mountain ranges is, from the west, the Appalachian Mountains of North America, across Europe, the Iberian Peninsula, the southernmost part of England, Belgium, Northern France, Central Germany, West of the Czech Republic. Furthermore, as the second stage, the old Tethys sea subducted under the Lauracia continent, for extension to the east, Tenshan, Altai, and Great Hingan mountain ranges of Central Asia were formed at the subduction zone. Further going to southward along to the subduction zone, from the mountain ranges of the eastern part of the Indochina Peninsula, it reached from eastern Australia to the Antarctica at the subduction zone of Panthalassa Ocean.
The Sinmeria subcontinent, which was on the north side of the Gondwana continent, moved northward and collided with the Laurasia continent as the Paleo-Tethys Sea disappeared. A mountain range extending from northern Iran to Afghanistan was formed. The sea between the Gondwana continent and the Sinmeria subcontinent expanded, opening the Tethys Sea. By this time, two land masses, Yangtze and China-Korea lumps including North China, collided with the Siberia continent.
Along the Caledonian orogeny stage, the Iapetus Sea became a land in the Silurian period. In the Silurian period, plants moved on the land, arthropods followed them. Furthermore, fossils of plants with vascular bundles have been found at the end of the Silurian period. During the Devonian period, forests were formed, and freshwater fish, insects, first amphibians (Ichthyostega) and others evolved to adapt to life on the land. The Rheic Sea closed in the late Carboniferous period by the Variscan orogenic movement. In the Carboniferous period, forests (scales) of large trees and conifers, which are gymnospermae, appeared in low humidity areas. In the Permian period, a variety of insects and other arthropods have emerged, including mammalian ancestors and primitive reptiles, which can enjoy a complete land life. Pushed by two orogenic movements, organisms accelerated adaptation and evolution to the land life.
A huge coal field that exists from North America to Europe now originates from plants that flourished during the Carboniferous period. In the state of West Virginia in the United States, a coal layer of 17 meters thick formed over 350,000 years are overlapped in 117 layers.
The ozone layer was completed in the Silurian period (about 450 million years ago), then plants were able to evolve on to the land. In the long Devonian period, the fern plants equipped stomata that regulate evaporation of water, fibrovascular bundles carrying water, and spores resistant to dryness. They formed large forests during the Carboniferous period. Fern plants could not leave the waterside because their fertilization requires liquid water in their life cycle.
The oldest tree in the world, Cladoxylopsid, is a tree similar to a palm trees about 12 meters high in the Devonian period (393 million to 372 million years ago). As a result of analysis of the fossils, a large number of pillars of the wooden part forming the vascular bundle were lined up to form a hollow trunk. The common ancestor of angiosperm plants and gymnosperm plants is thought to be 310 - 350 million years ago (carboniferous period).
Because not so many animals were landed which ate plants, the large forests fell down then stacked and deposited as they were. That is, they were buried the carbon under the ground. As the settlement of accounts, the oxygen produced by photosynthesis was reminded in the air, the oxygen concentration in the atmosphere rose. At the time of plant landing, oxygen in the atmosphere was about 1%, but it reached 30% or more (now 21%) from Carboniferous to Permian period (350-250 million years ago). The Gondwana continent, which was in the southern hemisphere, was covered by glaciers 300 million years ago in the middle of the Carboniferous period. It is thought that the concentration of carbon dioxide in the atmosphere has decreased as a result of the great prosperity of land plants.
Arthropods landed after the plants. From the stratum of the late Silurian (415 million years ago), fossils of scissors (spiders, ticks) were discovered and this is the evidence of the oldest crustacea on the land. Because arthropods were covered with shells, they are relatively resistant to dryness. Arthropods were able to live on the land if equipped with a mechanism to take in oxygen directly from the air (stigma. pore opening in the body surface of the stigma is called as spiracle).
Fossil footprints of huge arthropods, eurypterid (330 million years ago), were found in the northern part of England. From the size of the footprints, it was presumed that the body length is 1.6 meters and the width is 1 meter. In addition to the traces marked with three pairs of feet, the traces of dragging the tail remained clearly in the middle, not in a state floating in the water. But it is thought to be a trace that went out of the water and was walking. Eurypterid is an arthropod that is close to contemporary crabs or scorpions that were extinct before 250 million years ago.
The ferns and the arthropods were making soil on the land that had been the desert until then. Soil is a mixture of weathered products of rocks covering the earth's surface and degradation residues of plants, composed by coarse inorganic matter, colloidal inorganic matter, organic matter, microorganism, soil solution, and soil air. It is essential for stable ecosystem on the land.
Arthropods cannot grow huge on the land. Because the weight of the exoskeleton that supports the body is too large to maintain, the larger muscles are required to the heavier exoskeleton. This made the volume of exoskeleton be limited. Depending on muscle performance, the upper limit of the size is determined. Also, since the stigma is a device that passively takes in oxygen, aerobic respiration cannot be sufficient for them.
As the oxygen concentration rose from the Carboniferous period to the Permian period, the breathing problem of arthropod was solved. Insects had been able to evolve to huge size. Since the Permian period, the enormous coal field could not be formed, because the large insects began to eat plants. After that, insects became natural predators of plants, and for 300 million years, the deep symbiosis was developed between them. That is evolved and developed, the battle between insects and plants, and also dependence between them.
It is thought that adaptive emissions of insects occurred during the Carboniferous period. The reason is that insects invented the wings and advanced into the three dimensional world in the air. The oxygen concentration in the air rose greatly during the Carboniferous period. Insects that have wings and fly in the sky appeared 300 million years ago (the Carboniferous period). About 250 million years ago (the Permian period), the current insects almost appeared.
It was extremely warm from 270 to 250 million years ago and the average temperature was 10 C higher than the current temperature. The forests of fern plants flourished and huge insects were flying around. In the early years of Permian period, the Pangea supercontinent was established. The Siberia continent collided with Pangea super-continent, and almost all the land was put together as one super-continent. The Pangea super-continent was like a crescent (C shape) divided at the center with the equator. The big ocean surrounded the continent is called Panzalassa. On the east side of the continent (inside the crescent shape), there was an ocean called the old Tethys Sea, with small continents and islands dotted around.
The emergence of amphibians was the late Devonian period. Although the center part of continents was dried, large forests created a cradle environment that maintained moderate humidity. From Amphibian, amniotes were branched, which produce eggs with shell, and expanded their habitat to more dry land. The catalogue of creatures at the time when they started to advance to the land are not organized, many species were extinct. From the amniotes in the Permian period, the diapsids (ancestors of dinosaurs and reptiles) and snapsides (mammalian-like reptiles, ancestors of mammalian) evolved. Mammalian-like reptiles, such as Dimetrodon, established their hegemony on the land, and their size was reached to about 3.5 meters.
In the Permian period, there were various plants, huge amphibians and reptiles inhabited in the world. Among them, abundant fossils were found of mollusks, echinoderms, and brachiopod from the shallow sea sediments of the Permian period. Trilobites and others were prosperous. In plants, gymnospermae such as Ginkgophyta and Cycads also began to prosper in addition to fern plants.
A large number of insect fossils were discovered in the northwestern part of China during the PT mass extinction (233 million years ago). Insects are divided to the one that undergo complete metamorphosis (have the pupae period) and another that undergo incomplete metamorphosis. The insects that undergo incomplete metamorphosis are older in evolution. In this discovery, 28 families of insect fossils were found. Insect diversification occurred 100 million years earlier than expected, including many fully metamorphosis insects.
At the end of the Permian period (250 million years ago), the greatest extinction occurred in the history of the Earth. At that time, 96% of marine invertebrate species have disappeared. The extinction of the Guadalupian Age occurred 7 million years ago from the PT extinction. The cause is Emeishan Traps in southwestern China. Mt. Emeishan is a mountain in Sichuan, China, around which basalt lava has spread. It was mainly active from 262 to 261 million years ago and produced a large amount of lava of about 1 million cubic kilometers. The Great Extinction at the end of the Permian period was a huge eruption called the Siberian Trap, and the great extinction at the end of the Guadalpian Age was an eruption of the Emeizan Trap.
The oceanic plates that subducted to the surroundings of the Pangea super-continent began to fall toward the nucleus of the Earth at the same time, and as a back-action, a huge super hotplume occurred toward the surface of the earth. A huge volcanic activity occurred in the ancient China, a large eruption lasted about 600,000 years. This activity is said to make the Siberian flood basalt. The Earth was covered with a large amount of volcanic ash, and the plant died due to cooling and darkening. After that, the atmospheric carbon dioxide has doubled with the gas from the volcano activities, and the average temperature had risen by 5 C due to the greenhouse effect. The rise in temperature caused the methane hydrate to collapse, then the released methane further accelerated the greenhouse effect. It is thought that oxygen deficiency was long lasting because methane burned and plants were decreased. Clams with an evolved respiratory system seemed to be able to survive in this change. Unicellular Fusulina species and trilobites proliferating for a long time had been extinct. Small number of Corals, Sea lilies, Brachiopoda, Bryozoa and Amonites were left in the following Triassic period.
Not only in the ocean but also on the land, living organisms have been extinct in large quantities. Mammalian-like reptiles also experienced several extinction phenomena over the long term in the late Permian period. Survivors on the land were organisms with an efficient respiratory apparatus. In the case of mammalian-like reptile, they separated nose and mouth, and were breathing using the diaphragm. In the other case, like birds (also dinosaurs), survived animals developed a circulatory respirator with air-sacs in addition to the lungs. Plants are not extinct so much because descendants can be left as seeds resistant to dryness, although by the end of the Permian period, the plants were also largely extinct.
The Mesozoic era started from the Paleozoic era with the end of the Permian mass extinction. At the beginning of the Triassic period, the ecological space on the Earth was largely empty and not much organism. In the Triassic period, reptiles evolved greatly, and eventually the dinosaurs flourished on the Earth.
The evolutionary mechanism at the gene level is considered to be based on gene duplication. Examining the genes, many genes with similar nucleotide sequences or amino acid sequences are found and each has a different function. It is reasonable to think that gene duplication occurs, then the function has differentiated. Gene duplication may occur partially, sometimes doubling the entire genome. Two stages are hypothesized that genome had doubled.
One is the time when a eukaryote was born, about 1.5 billion years ago. In prokaryotic E. coli, the genome size is about 4,377 genes, the eukaryotic yeast genome size is 5,538 genes, and the malaria parasite is 5,268 genes. Although not doubled, new genes were added dramatically.
The increase in genome size allowed living organisms to afford to diversify the genes and became the basis for the Cambrian great explosion 600 million years ago. Multicellular organisms have double the number of genes compared to single cell organisms. The slime mold, which is usually a unicellular organism like ameba, but at the time of reproduction it becomes multicellular organism, has 12,500 genes. C. elegan, which is a multicellular organism, has 19,893 gene and sea urchin, which is a protochordata (ancestor of vertebrate), has 15,852 genes.
The second doubling in genome had occurred in the Ordovician and the Silurian period, because the organisms appeared whose genome size was further doubled. The vertebrate pufferfish has 27,918 genes and the human being has 22,287 genes. Fish, amphibians, reptiles, birds and mammals are thought to have about the same number of genes. For comparison, a rice plant has 37,544 genes.
In plants, tetraploid, hexaploid, etc. can be made by drug treatment. The polyploid increases the number of chromosomes, but not the number of genomic genes. Wheat was selected hexaploid by artificial choice, to increase the yield. When genome is multiplied, the size of the body tends to become large. The giantization found in mammalian like reptiles and dinosaur might be related to multiplication of genome size. In fish and amphibians, polyploidization is often observed, but not seen in reptiles, birds and mammals. Related to this or not, sex determination is strictly regulated by the number of genes in birds, reptiles, and mammals.
It is not only the case the entire genome duplicated. Multiple genes with similar sequences are found in the genome. It is called gene family. The largest gene family in the human genome is the GPCR superfamily, which has over 1000 members. Also, the Immunoglobulin superfamily contains 765 genes. These genes are considered to be duplicated and diversified from one ancestral gene. The gene duplication mechanism is thought to be a mistake (transfer) at the time of replication, gene recombination, or gene transfer utilizing replication function such as endogenous retrovirus.
There are cases where functional units are duplicated in genes. In other words, many genes have the same functional unit (a gene fragment). In particular, you can find a gene that joins two functional units. Partial duplication in genes in many cases occurs in exon as unit. It is believed to be caused by gene transfer utilizing replication function such as endogenous retrovirus.
Under the state where the function is hidden, that is, even if the gene changes but not affect the phenotype, so it is expected that various trials and errors can be made. Motoo Kimura, who advocated a theory that the most of the evolution at molecular level would be neutral, explained that the mechanism is essential to hide the non-neutral mutations for evolution at the phenotype level. Gene duplication and sexual reproduction are thought to hide such mutations.
Meanwhile, it is also necessary to have a mechanism for putting out the accumulated mutation at once. Such an opportunity is considered as a major change of the earth, or the environment. Molecular mechanisms are under study in which gene mutations are manifest. Heat shock protein, which is one of the candidates, is produced when the cell is subjected to stress, correct three-dimensional structure of the denatured proteins by stress. It is pointed out that the mutation in the heat shock protein may cause many new mutated genes to function, which were originally dormant.
Mesozoic era (Triassic, Jurassic, Cretaceous) came after mass extinction at the end of the Permian period 250 million years ago. The Gondwana continent is a huge continent composed with Antarctica, Australia, Africa, South America, and India, located in the high latitude region of the Southern Hemisphere and was the largest 300 million years ago. In the Triassic period, Pangea supercontinent existed. From the present Turkey, via Central Asia, to South China, the old Tethys sea sank under the Eurasian continent, and was about to disappear. The Tethys Sea had expanded at the south of the region through the present Tibet, Turkey and Iran plateau.
Large-scale computer simulation of mantle convection in the three-dimensional global sphere taking into consideration the physical parameters of the mantle was carried out on the process of the division of super continent Pangea 200 million years ago. The state of continental movement from 200 million years ago to the present was examined. On the actual Earth time scale, the great events on the Earth surface after the Pangea division, such as the expansion of the Atlantic sea and the collision Indian subcontinent with the Eurasian Continent, which moved at high speed to the northward, was reproduced.
In particular, anomaly high temperature of the mantle due to the heat shielding effect beneath the Pangea supercontinent might largely contribute to the division of Pangea supercontinent. The heat accumulated under Pangea was interpreted to have expelled from the mantle to the surface through the rifts. The main driving force that the Indian subcontinent moved northward at high speed was presumed to be a cold plume developed in the northern part of Tethys sea immediately after Pangea division. From the three-dimensional structure of the current mantle constructed by seismic tomography, the low-temperature region is confirmed deeply in the mantle ahead of the cold plume. India subcontinent without a subduction zone still continues northward, indicating that the driving force of continental migration is also a cold plume.
In the early Triassic period, the oxygen concentration fell to the lowest level ever since the Proterozoic era, at 10-15%. Living organisms adapted to that age were characterized by their body plan. The cardiac morphology is more advantageous in the 4-chamber heart (birds, mammals), where the arterial blood and venous blood are completely separated, than in the 3-chamber heart (amphibian, reptile). A good example is a dinosaur. Dinosaurs had a heart with 4 chambers and air sac. In reptiles, owing to the legs protruded sideways then advanced while twisting the body, the lungs are pressed and their breathing is less efficient. In contract, dinosaurs have the foot downright from the body. Also, the diaphragm was developed. The bird's air sac system has a one-way flow of air from the lungs to the air sac and is good breathing efficiency. Reptiles, together with ammonite, are creatures representing the Mesozoic era. In the Triassic period, reptiles expanded their living area to the land and the sea.
Dinosaurs evolved in various ways during the Triassic period. The symbolic stratum is in the Carnian period (237-227 million years ago). The characteristic dinosaurs have evolved during this short 10 million years. The ancestors of Stegosaurus and Triceratops, Brachiosaurus, and Tyrannosaurus have emerged. During this period, it was rainy and warm, and the interior of the giant continent was dry and hot. There are no flowers, no grass, no bird. Mammals have found as fossil teeth. Coral ancestors were born in the sea. It is believed that the Langeria eruption at 232 million years ago would have caused the warming for millions of years. A huge basalt belt remains with a thickness of several kilometers that extends from British Columbia to Alaska in Canada.
Among the gymnosperms, the ginkgo species that appeared in the Permian period gradually extended their living area. In the Triassic period, the ginkgo species, pine woods, and cycads mainly formed the forests, where genuine ferns flourished under the tree. Early gymnosperms, ginkgo and cycads had naked ovules directly exposed to the outside air. In pine trees, ovules were covered with scaly organs made by deforming branches and leaves, forming cones and thus were protected. For fertilization, sperm cells directly extended a pollen tube to egg cells. This mechanism enabled the pine trees expand to almost the whole area on the Earth.
At the end of the Triassic period, magma activity became vigorous in central Atlantic area, raising the concentration of carbon dioxide in the atmosphere. As a result, the temperature rose globally and 47% of the creatures of the genus died out.
When the Pangea super continent was torn, large volcanic activity occurred on land. So there was mass extinction when Jurassic period began. The animals were extinct such as giant amphibians or the Therapsida that connects the dinosaur and the amphibian. Instead, in Jurassic a group of reptiles called dinosaurs came up to the top of the ecosystem. Taxonomically we call Saurischia and Ornithischia as dinosaurs. Dinosaurs are one of archosaurs, along with Pterosaurs and crocodiles. Pterosaurs that can fly in the sky and Plesiosaurs or Ichthyosaurs that lived in the ocean are not included in the dinosaurs. Dinosaurs were so prosperous to differentiate into various species.
Mammalian ancestry is Synapsid. Synapsids flourished in the Permian period, divided into reptile-like Saurischia and mammal-like Therapsida. The Saurischia were extinct by the late Permian period (2.5 million years ago). Therapsida survived in the early Triassic period, but died out in the late period. It is thought that mammalian ancestry evolved from Therapsida in the late Triassic. At that time, it is thought that they were still bearing eggs, but that they raised their child with milk.
Dinosaurs were able to walk with legs stretched right beneath the body, moving back and forth. Therefore, small dinosaurs have high exercise capacity and feed on other small animals. In addition, the legs extending right under the body were able to support a huge body. Large body was a major weapon on land where was easy to dry and the temperature changed drastically.
In addition, the newly emerging gymnospers formed a large forest. The ferns could grow only in places with high humidity, so the dry inland of Pangea continent was a wilderness. In the Jurassic period, gymnosperm plant made big forest and attracted lives. Pterosaur and birds flying in the sky were appeared. Dinosaurs seem to be separated into homeothermometric and heterothermometric animals. Therapoda (herbivorous) and Ornithischia which had a huge body are heterothermometric. Small Terapoda (carnivorous) is highly likely to be a homeothermometric animal.
Angiosperms have flowers and make seeds. The basic structure of flowers is composed of stamens, a pistil and petals. Flowers are soft tissue and are rare to be remained as fossils, but it is estimated that they appeared 140 to 250 million years ago (Triassic period). An evolutionary phylogenetic tree was created by the eFLOWER project integrating the flower shape and fossil data by many botanists. The first flower appeared 140 million years ago and was presumed to have several petals.
Coral reefs were spreading in Tethys Sea. The northern coast of the Tethys Sea goes from the current Southeast Asia to the Middle East (India is still far south), reaching Europe and North America. South runs through the north side of India from northern Australia to the Arabian Peninsula, North Africa. Tethys sea was contact to the Atlantic Ocean, which was being opened, and the west of the Tethys sea extends to South America.
A new movement of crust started and continued from the end of the Jurassic period to the Cenozoic era. One was the opening of the Atlantic Ocean. The rift extended to Gondwana continent, so South America and Africa were separated. Antarctica, Australia and India were separated from Africa and moved northward, except for Antarctica. Along with this movement, the Tethys sea began to subduct under the Eurasian Continent.
The division of the continent created a global equatorial current. This ocean current ran round of the Earth at equator and was always warmed, so it did not cool down. The Tethys Sea is thought to be very warm because it was on the course of the global equatorial current. The Tethys Sea is thought to be full of food because many fossils of coral are found there in100 to 70 million years ago. There was no ice sheet in the Arctic or Antarctic.
In the Mesozoic era, something was made indispensable for modern society. It is oil in the Middle East. The Arabian plate, which accumulated oil later era, was located on the north side of the Gondwana supercontinent from the Precambrian period through the Mesozoic era, facing the big but unstable sea. Since the Gondwana continent was in the south, the Arabian plate was stably maintained within the equatorial region, not to collide with other continents, nor sink into the mantle.
The Arabian plate sank in the Tethys Sea in the Mesozoic era, and it seems to have accumulated a large amount of organic matter there. The temperate Tethys sea gradually closes, not only the Arabian plate, but also the North African and American oilfields were produced. The Arabian plate is currently colliding with the Eurasian Continent, raising the Zacros mountains of Iran. The Arabian plate is going to collide into the huge Eurasian Continent so the current Middle East oil fields will also be destroyed.
From the analysis of the genome it is estimated that the ancestors of marsupials and placental mammals diverged 180 million years ago. Fossils of the oldest marsupials were found in China earlier in the Cretaceous period 125 million years ago. This Marsupial is estimated to be as large as rats 15 cm in length and weighing 30 grams, climbing trees, eating insects etc. Because Marsupial remains in South America and Australia far from China, Marsupials are expected to live on the entire continent. Likewise, a fossil with size of dogs or cats of about 130 million years ago was found in China. The bones of the dinosaur child were found from its belly, and the image that the mammals lived overwhelmed by the dinosaurs should be corrected.
The Australian continent and Antarctica became to have independent ecosystems separated from Africa, South America and the Indian subcontinent by 150 million years ago. Noteworthy animals are marsupials. Especially platypus has properties of both mammals and reptiles. Mammals with a uterus appeared on other continents, and eradicated marsupials. Evolutionary phylogeny of mammals depends greatly on continental migration.
In the Cretaceous period, volcanic activity was active, the concentration of dioxide was high, and it was warm. Evaporation on the surface of the sea was so intense that sea water with high salt concentration accumulated in the deep ocean to stop ocean circulation. The ocean floor of the deep ocean became poor in oxygen (ocean anoxic case). The accumulated organic matter was deposited as black shale and became the source of oil.
Dinosaurs in Cretaceous period became warm-blooded animals, and those appeared that sit on eggs and that feed baby animals. If it evolved as it is, those used free paws appeared, finally species like mankind appeared? However, the dinosaur existed on Earth for about 150 million years, but no one with civilization appeared.
Fossils of dinosaurs that had feathers on the body surface have been found one after another. For a long time, a question mark is attached to an Archeoptery that was originally recognized as a bird fossil, and the feather dinosaurs found in China and primitive birds "Confucius bird" are thought to be the origin of birds. In this case, the appearance of birds is early Cretaceous (about 130 million years ago). The dinosaur survived the mass extinction by the meteorite, which told the end of Mesozoic era, turned out to be a bird.
Angiosperms have changed for gymnosperms. Changes in the plant world also influenced the types of dinosaurs and changed from Jurassic types to Cretaceous ones. Sauropods, Apatsaurs (Brachiosaurs etc.) and Stegosaurs which were more and more gigantic became extinct, Iguanodon and horned dinosaurs (Triceratops etc), which had a more mobility and lived as a group, replaced them.
Angiosperm appeared first in the Cretaceous days when the dinosaurs were standing, then prospered greatly afterwards. It is thought that the species differentiation of insects occurred at the same time is due to co-evolution of angiosperms and insects. Colorful flowers with honey produced by Angiosperms attracted insects, and symbiotic relationships were established between them. Among insects which are prosperous now, bees, flies, butterfly and beetles diversified since early in the Mesozoic era.
At the end of Cretaceous period, 65 million years ago, the living world experienced the second largest extinction in history. The cause is said to be a collision of a meteorite. A comet or small celestial body about 10 km in diameter had fallen at the site of the current Gulf of Mexico. Many creatures were sacrificed by the tsunami caused by the direct effect of the collision. Meanwhile, as an indirect effect, a lot of dust and gas soared to the stratosphere to block the sunlight then to make the Earth cool. The plant was temporarily hit hard. The animals at the upper level of the food chain were received the greater blows. It became a big trigger for extinction of the dinosaurs.
A meteorite collision that extinguished dinosaurs made craters with a diameter of 180 km in Chicxulub region of the Yucatan Peninsula, Mexico. It is estimated that when a 10 km diameter meteorite collides at 20 km/h, the temperature reached about 10,000 degrees at the collision surface and the pressure reached 600 giga pascals. Since 10 km is more than twice the depth of the ocean, not only the seawater but also part of the plate beneath the sea bottom would evaporate in an instant.
Several birds are believed to have survived the devastating event which extinguished dinosaurs 65 million years ago, and since then, they has rapidly evolved into a wide variety of species of around 10,000. Sexual urges that copulate with or attract affection of opposite sex drove a rapid evolution of 15 kinds of pigment genes related to feathers and its decoration in birds. The ability of birds to chirp and imitate sounds appears based on the same neuronal circuit as seen in humans. However, the evolutionary path that humans have reached this ability is different from birds.
Mammals forced out dinosaurs lacking adaptability to the environment, and placed at the top of the food chain instead during a short period of time. After the extinction of the dinosaurs, mammals established the status of predators on the Earth. In the history of evolution, as it has been several times in the past, mammals, a new predator, have become very diverse and have advanced into an ecological niche with changing forms and lifestyles.
Researchers in 20 countries spent four years and deciphered the genomes (total genetic information) of 48 species of birds such as owls, hummingbirds, penguins, woodpeckers and so on. In addition, among the reptiles, they compared the genomes and genes of three crocodiles with birds, which have the closest relationship to reptiles. They discovered that there is a big difference in the rate of evolution. While birds were much faster to acquire new genetic traits, there was hardly any change in crocodiles that branched off from common ancestry with birds and with dinosaurs about 240 million years ago. It is about 116 million years ago that teeth have disappeared from birds.
As the super continent Pangea divided into the several continents, shallow sea was open along the edges of continents as the Atlantic basin opened. Phytoplankton grew massively and more oxygen released into the atmosphere. The plankton carcasses settled and the mass of organic matter increased in marine sediments dramatically. Because the organic matter was not decomposed, the oxygen concentration in the atmosphere almost doubled. The metabolism of birds and mammals requires considerably more oxygen than reptiles. In order to grow a baby in the body (with the placenta), the oxygen concentration in the atmosphere needs to be high. The diversification of placental mammals coincided with the era of high oxygen concentration in the atmosphere.
Due to the outcome of the genome project, it is known that more than a third of mammalian genomes are retrotransposons and the related nucleotide sequences. Retrotransposons are "jumping" genes from one place in the genome to another. Among these, the Peg10 gene, which is essential for the formation of mammalian placenta, was discovered. By evolutional genetic clocks, it seems that placenta species were born with the jump of Peg10 gene 170-140 million years ago.
Mammals did not morphologically evolve so much during the long Mesozoic era, but should have developed significantly in terms of function. They had evolved various abilities necessary for survival in a new environment in the niche of the dinosaur ruled ecosystem. For example, ability of hearing and smelling to live in a dark environment such as night or inside of cave and information processing ability to detect foods or danger. A reliable breeding method of raising a child with milk. Originally milk was sweat; mammary gland was evolved from sweat gland. Omnivorous ability of eating various things by diverse teeth. The maintenance of body temperature and possibly habits like hibernation.
It seems that the basic system necessary for emotions had evolved 100 million years ago when various information was put together. They are the amygdala that controls fear and the neuro-hormones that control feelings, such as dopamine, oxytocin, vasopressin, endorphin, etc.
It is said that Placental mammals (Eutherian) appeared on the Old World on the earth (North America?). The more capable Eutherian evolved while forcing Marsupials out and expanded their living area. Since South America and Australia were isolated before Eutherians invaded, marsupials were to be preserved. It was several million years ago that the Americas of the South and the North were connected (the Panama Strait was made).
Mammals are the animal representative of this era, in addition, birds and teleost in oceans also largely evolved in the Cenozoic era. The evolution of mammals in the Cenozoic era can be seen as a change in the number of species. Many ancestral shapes of mammals appeared during 30 million years. After that, the Earth suddenly began to cool down, and many groups were extinct. Ancestors of existing mammals came in 20 million years ago. The categories of living things are species, genus, family, order, class, and phylum. The basic unit at the time of extinction is the family.
The Cenozoic is divided into Paleocene, Oligocene, Eocene, Miocene, Pliocene, and Pleistocene. Among them, the biodiversity has dramatically increased in Pliocene and Pleistocene. This is because the frequency of appearance increased as well as the frequency of extinction. This is called the species turnover speed. In primates the turnover speed increased to Pleistocene, somewhat later than the other species. Turnover would be the driving force of great evolution eventually.
Looking at the balance between extinction and appearance based on the family, 35 families appeared per 10 million years, during first 40 million years in 65 million years. The number of extinctions has increased little by little, almost the same as the number of appearances in the Oligocene (34-24 million years ago). After that, the number of occurrences decreased, and it became 20 families per 10 million years. The extinction number rapidly increases after entering Pleistocene, it becomes 80 families calculated as per 10 million years. It is the influence of homo sapiens.
Whatever a mammal or a bird, their characteristic is the development of the brain. The species in which a pair of male and female makes a unit to live tend to have a significantly larger brain compared to the size of the body than other similar species. In the case of birds, the brain is even bigger of a species whose mating pair lasts for a long time. It is suggested that crows may possess intelligence equivalent to that of primates because they have the ability to make suitable tools without failure.
In dinosaurs, all teeth were almost the same shape, whereas mammals differentiated function in front teeth and back teeth. They can chew and grind food better. Among mammals, the best adaptation to eat plants is Artiodactyla, such as cattle and deer. This group can keep a plenty of plants in the stomach, soften them, then returns to the mouth and grinds and drinks again. This action is called rumination. By ruminating, they can eat and digest hard plants.
In the Cretaceous period, angiosperms, which have flowers, are diversified rapidly instead of ferns and gymnosperms. Angiosperms are flowering plants that are now normally found around us. The first reliable evidence of angiosperms is pollen fossils of about 130 million years ago at the beginning of the Cretaceous. A major group appeared in late Cretaceous. Angiosperms provide pollen and honey to insects which come to carry plant pollen. The interaction between both organisms is enriched and both have diversified. The basis is a bee. The ancestor of the bee has dates back to 100 million years ago (Cretaceous). Insects such as bees are stored in amber.
Angiosperms are thought to have originated from gymnosperms, but it is not known yet which gymnosperm was an ancestor. The aquatic plants, Hidachiaceae and Sirens, are the first angiosperms that appeared in the Mesozoic era. In Hidachiaceae, the maternal tissue supplies nutrients to seed common to gymnosperms (conifers), not embryonic tissue like angiosperm plants.
Currently, angiosperms have about 400 families, 250 thousand to 300 thousand species. In the Cenozoic era Tertiary period, a genus that is flourishing to the present has appeared. Like mammals, the current species came out about 10 million years ago, and the species that characterize the Tertiary period disappeared by about 2 million years ago.
Gymnosperms and angiosperms have hard bodies derived from vascular bundles. Jurassic dinosaurs could not grind hard plants. Huge thunder dragon had a stone in their stomach. It is like a gizzard of birds. Teeth played only a role of tearing off the leaves. Cretaceous herbivorous dinosaurs are thought to be able to grind plants by developing cheeks and creating grinding teeth.
Angiosperm offers mammals and birds with fruits loading seeds which have shells not to be digested, and has taken a strategy to expand the breeding area. Plants are always in a position to be eaten on the food chain, so this strategy is on the evolution of symbiosis just like insects.
Rapid warming of climate occurred 55 million years ago (Paleocene-Eocene Thermal Maximum, PETM). Its cause as theory is thought to be due to methane hydrate collapse, as well as others, large changes in volcano activities or in ocean currents. It was warm until around 40 million years ago. It was so warm up to the mid-latitude region as subtropical, and even in polar regions, it was subarctic climate not arctic. At this time, vegetation of the Earth was shifted from gymnosperm to angiosperm rapidly. At the same time, mammals also spread all over the world.
Angiosperms are divided into monocotyledons and dicotyledons. The origin of dicotyledons seems to be older. Monocotyledons have the strongest reproductive power in plants. The gramineae family is well known. Its speed of photosynthesis is also great, growing fastest if the environment is good. It is generally an anemophilous flower. It forms grasslands in areas where precipitation is so small that forests cannot be formed.
Dicotyledonas are made up of a large number of species which are greatly different in form. There are various shapes, such as trees, flowers and vines. There are some strange plants with only leaves and roots like duckweeds. Most of them grow naturally, but some are parasitic like mistletoe. The world's largest flower Rafflesia is a family of violets, but it is a perfect parasitic plant. Their habitat environments are also diverse, ranging from desert cactus to water lilies and water hyacinth.
When classified roughly, monocotyledonous species do C4 photosynthesis. Even under the environment where the carbon dioxide concentration is lower, they grow faster than the general C3 type photosynthesis plant, and are strong against drying. C4 plants appeared around the late Cretaceous and rapidly increased 7 million years ago when the atmospheric carbon dioxide concentration became low. Since 2 million years ago, the glacial period with low carbon dioxide concentration started. They became dominant in temperate areas.
Since the end of the Tertiary, the Earth has cooled down and cold winter has come to visit, so annual plants prosper. Annuals do not have hard stems, growing according to the season, leaving a large number of seeds before the winter, their body withers in the winter. In the cold winter, they spend as seeds living long time. Therefore, generation change is fast. In addition, deciduous trees drop leaves in autumn and finish production activities and overcome the cold winter. This was also a consequence of adapting to cooling, and it was a way of life not existed in the Earth until then. The major extinction in the past is always caused by cooling, and the greatest adaptation strategy for plants against cooling may be an annual plant. Insects that live in temperate regions also produce eggs and pupas to be resistant to cold. They live one generation in a year.
The protruding motions on each continent made plateaus spread inside the continent. The cooling has progressed from around 5 million years ago. Dry climate spread in the interior of the continents, and plants of the grass family, which is the C4 plant, developed. Prairies were made on the continents. A new kind of herbivorous animals developed that adapted to such grasslands. The monkey of our ancestor also went out to savanna from forest. They lived on trees in forest but walked on the ground with two legs in savanna. In Africa, climate change has increased and drying has progressed along with the cooling since 3 million years ago. At the same time in flatland, it slowly switched from the forest to the grassland. The time just agree with the appearance and prosperity of the hominid.
The Cenozoic is divided into the Quaternary period, or glacial period, and those before, the Paleogene and the Neogene period. Results obtained by drilling of the floor of the Arctic ocean revealed the climate change during the past 55 million years in the Arctic. It has been cooling down over the past 55 million years, especially 45-25 million years ago, a large area of the Earth has cooled because concentration of carbon dioxide in the air dramatically decreased. This is the boundary between the Paleogene (65-23 million years ago) and the Neogene (23-2.5 million years ago).
The Indian continent collided Eurasia continent, the Arabian Peninsula collided Turkey, Africa approached Europe. The Himalaya and the Alps mountains began to uplift 15 million years ago. There was also a large volcanic activity. The gigantic mountains retained glaciers and contributed to the cooling by the albedo effect. In addition, due to rapid erosion, calcium ions flowed into the seawater and carbon dioxide in the atmosphere decreased. This is also one of reasons of the global cooling.
The Indian continent moved extraordinary fast. It has been moving 20 cm each year. The Australian continent is several cm every year, and the Pacific plate on which the continent does not ride is also about 5 cm each year. The Indian plate carrying the Indian continent has sunk under the Eurasian Continent. Fifty million years ago, the Indian continent collided the Eurasian Continent, then the sea floor, which was in front of the Indian continent, was pushed up onto the plate in the form of a ride over the Indian plate. This is the Himalayas mountains. The lifted part of Eurasian continent forms Tibetan Plateau. The Indian plate sinks into a vast Ganges plain with low altitude.
Antarctica was at the southern end of Pangea supercontinent, but covered with green plants long ago. An ocean current flowed with Tasmania island about 35 million years ago, and Australia gradually separated from the continental mass of the south Pangea. About 30 million years ago, Antarctica arrived at its present position, and the Drake Strait was formed between the Continent of South America, which had contacted at the last. As a result, a cold current of ocean, called Antarctic Currents, formed around the Antarctic continent, which keeps warm current away from Antarctic continent. Forests remained in Antarctica until 25 million years ago.
A deep ocean current was formed from Antarctica to eastern New Guinea 15 million years ago. This deep current conveys cold seawater to throughout the Pacific Ocean, which resulted in cooling down the entire Earth. Antarctica froze as it is now, a thick ice sheet developed. The ice sheet covered the whole land 9 million years ago. The development of the ice sheet and the cooling of the global environment after 5 million years ago proceeded at the same time. The thickness of the ice sheet covering Antarctica reaches 4000 m. Due to the formation of ice sheets in Antarctica, the sea level of the world fell about 70 m. Also, the Antarctica continent sank 500 meters by the weight of the ice sheet. The huge ice sheet in Antarctica affects the global environment as a source of cold heat.
About 10 million years ago, high-temperature mantle material slowly rose just under the eastern part of Africa, thus the African continent began to split. The African Great Rift Valleys is a ridge that appeared on land, The valley penetrates the east side of the African continent in two rows from the north to the south. The end of the north turns into the Red Sea, heading to the Mediterranean Sea. The Africa continent is still breaking to the east and the west on the boundary of this Great Rift Valleys, and earthquake activity and volcanic activity continue in the vicinity of the Valleys.
The rift valleys can be seen in the Death Valley in the United States of America. Death Valley, Salt Lake of Djibouti in East Africa and the Dead Sea of Israel are lower than the sea level, and a lot of salt is deposited in the bottom of the valleys. Several million years later these places will become the sea.
The Gibraltar Strait connecting the Mediterranean and the Atlantic Ocean is a shallow strait with a width of 20 km and a depth of 200 - 400 m. Due to global declines in sea level and crustal deformation in about 5.6 million years ago, the Gibraltar Strait changed to the land. Iberian Peninsula and Morocco were connected, and Mediterranean became a lake. This era is known as the Messinian salinity crisis. During this period, Mediterranean seawater evaporated on a large scale. Gypsum and rock salt, called evaporative rock, are found in countries such as Spain, Italy, Greece and Tunisia on the Mediterranean coast. The layer of gypsum and salt continues to the Mediterranean sea floor. It was proved in the research project of the deep sea drilling program of the deep seabed in the Mediterranean.
About 5.3 million years ago, the water came back again, but the details of this greatest flood of this earth's history are only roughly understood. Drilling survey, seismic wave data, and research using numerical model suggested that this was a drastic change. It initially started with a small stream lasting for thousands of years, but 90% of the Mediterranean water flowed in less than two years. Such a sudden flood may make the sea level rise at a peak rate of over 10 meters per day.
The uplifting movement on each continent has resulted in rapid cooling down from about 5 million years ago when highlands and plateaus spread within the continent. There are currently two theories proposed as a cause of this.
One is the formation of Panama land bridge. The deep water that was flowing from the Atlantic to the Pacific Ocean was blocked by this bridge. And the Mexican gulf stream became largely to flow to the north. The warm Mexican gulf stream increased the amount of snowfall in North America. The ice sheet was expanded when it was cold to amplify the cooling. Greenland was a green island as it was named before, but it turned into an island of glaciers.
The second is the formation of the Himalayas and the Tibetan Plateau. These topographical elevations disrupted the atmospheric circulation of the Northern Hemisphere. The monsoon climate is established mainly in India and strengthened the Siberian cold weather in winter. This is a hypothesis that it caused cooling.
As the average temperature decreases, the amount of water vapor contained in the atmosphere decreases. That is, the amount of water carried into the land by the atmosphere decreases. Because the water is not carried to the interior of the continent, the central part of the continent becomes dry. In general, cooling is drying, warming is moistening. Cooling expands grasslands and deserts, global warming expands forests. Although contemporary global warming and desertification are often discussed on the same stage, the commonality of both is the result of human activities. The desert would shrink as global warming progresses without human activities.
A dry climate spreads in the inside of the continents, there are also development of plants of the grass family just so that the continents have large grasslands. And a new kind of mammal adapted to such grassland has evolved, such as ancestors of dogs and wolves, and horses. And the monkeys of an ancestor of mankind also went out to the grassland from the tree living of the forest, and walked on the ground with two feet. Tweet birds, called songbirds, developed greatly. It seems to be a driving force that dominated communication by singing voice, agile exercise ability.
Cenozoic terrestrial volcanic activity is well investigated. The volcanic territory of Yellowstone National Park moved from Oregon to Wyoming during 16.5 million years. This is because the North American continent has moved west over the hotspots. Large eruptions in Yellowstone National Park occur approximately once every 1.5 million years. The largest ones are the Idaho eruption 8.7 million years ago, followed by the large eruption 2.1 million years ago. Since they were about the same scale as the eruption of Toba volcano 74,000 years ago, it should have been accompanied by a temporal cold climate of several years..
From 2.6 million years ago to the present, the glacial and the interglacial time have been periodically replaced. This time is called as the quaternary period. According to survey of the ice sheet on Greenland, the cycle was about 40,000 years from 2 million years ago to a million years ago, and from a million years ago to the present, the cycle was about 100,000 years. When analyzing the cycle, several waves are overlapped. Several external factors are considered to affect the climate change, by changes in solar radiation amount, due to the change of distance between the Earth and the Sun (100 thousand year period), changes in the inclination of the earth's axis (period of 20 thousand years and period of 40 thousand years). However, changes in temperature, ice sheet volume, etc. are larger than those changes. Changes in solar radiation amount are thought to have been amplified due to air, ocean and continental arrangements, topography, and so on.
Loess began to accumulate in China in Loess Plateau from about 2.5 million years ago, most of which began in the quaternary period which started about 2 million years ago. It is estimated that the uplifting of the Tibetan Plateau would block the atmospheric circulation from the tropical zone and that the inland parts of China would dry out.
Glaciers widely covered the northern part of the northern hemisphere during the heyday of the glacial period, and a massive flood occurred due to the breakdown of the glacial lake every time the interglacial age. In the bottom of the Dover strait, there are evidences that devastating floods occurred twice, 400,000 years ago and 200,000 years ago. Due to the large flood, Britain Island would have been separated from the continent.
The last glacial period started 130,000 years ago. It became gradually cool with some fluctuation since then, until 18,000 years ago. The temperature rapidly rose from the glacial period to the modern interglacial period, because warming was accelerated as the glacier began to melt. It is estimated that rapid warming occurred as well as 130,000 years ago.
Changes in the global environment in recent years since the Industrial Revolution are comparable to catastrophes in the past. Since this environmental change is attributable to human activities, a new period classification of Anthropocene (Fifth century) named after Anthropogenic (by human activity) has been introduced in fields not related to classical geology. This time classification, the definition does not depend on the strata. The basic idea is the same as the classification of the geological age is decided by the annihilation of the species recorded in the strata and the large scale change of the global environment.
Before entering the evolution of mankind, I will summarize the history of the Japanese archipelago in two parts.
Among the rocks in the Japanese archipelago, the oldest are located in Kitakami Mountains in Tohoku district, or Hida mountains. It is thought that these rocks were not the accretionary prism but were accumulated in the shallow sea. It probably accumulated in the north side of the Gondwana continent before the Bariscan orogenic movement, and on the Panthalassa side of the China-Korean subcontinent. Estimated from the Paleozoic fossils included, it located in the southern hemisphere near the equator.
The origin of the limestone caves in Japan dates back to the Paleozoic era. The limestone body of the stratum contains fossils of Sea lilies and Fusulina, which are indicator fossils about 300 million years ago. The huge limestone body that creates limestone caves extends from Kanto to Tokai, Kii, Chugoku and Shikoku to the central part of Kyushu. The limestone body originates from coral reefs developed in the far south ocean. It is located on the basaltic sea mountain on the sea floor. The submarine volcanos that were born at a hot spot on the Pacific ocean floor have moved northward by the movement of the Pacific plate. Coral reefs and submarine volcanoes are considered to be accretionary bodies that detached from the ocean plate and accumulated at the plate boundary. In Mesozoic era, from Jurassic to Cretaceous periods, strata were formed around the bodies with sediments flowing from the continent of that time. They were taken in the Japanese archipelago formed later and appeared on the ground due to crustal deformation.
The Pacific plate has been driven down below the North American plate near Hokkaido, and the Kuril islands were formed at the top of the subduction zone. Below the Eurasian plate in western Japan, the Philippine's Sea plate was driven down, where the Ryukyu archipelago was formed. The Pacific plate was driven under the Philippine Sea plate and the Ogasawara Islands were formed.
It is in the midst of the Cenozoic period that the Japanese archipelago started to be formed like the present shape. The Japanese archipelago up to about 30 million years ago was located in the east edge of the newly created Asian continent, and there was no intense fluctuation. Two inland bays were present at a position of present Kyushu and Hokkaido, and plant fossils were deposited there. Most of Japan's coal was made of at this age. Inner Bays are a sign of the Japan Sea. Adducts from the Pacific plate were accumulated at the Sea near the continent.
The edge of the continent began to split 25 million years ago and moved to its present position 15 million years ago. The living organisms and fossils of dinosaurs that lived on the continent came to the Japanese archipelago on the edge of the continent. The Pacific plate came a long distance thus became cold and heavy. Thus it would sink at a large angle. The plate dragged in the continental margin, a small rising flow of mantle occurred inside the continent. As a result, the continent was stretched and torn. A huge fault activity occurred around East Asia mainly around 22 million years ago. Around 19 million years ago, a big fault was formed on the side of the Japan Sea and the ocean entered into the rifts. At the same time the eruption of the submarine volcano began. The activity of the volcano was very active, lava and volcanic ash spread throughout the region and accumulated in large quantities. Eventually the lowland expanded, the Japan Sea formed.
The same phenomenon was occurred between Australia and New Zealand. A drowned continent Jealandia is supposed, and at the edge of Jealandia again uplift occurred, New Zealand and New Caledonia were formed. Similar terrain is found in Kamchatka Peninsula, Taiwan, and Philippine Islands.
The Philippine Sea plate was born as a result of a new plume 52 million years ago. It expanded northward, began to subduct from the Ryukyu Trench, through the off coast of Shikoku, then reached the Ogasawara Trench in 20 million years ago. As a result, the volcanic islands that were in the border between the Philippine Sea plate and the Pacific plate have been added to the central part of Japan from 14 million years ago. In addition, due to this change, a large amount of magma was supplied to the basement of western Japan, the caldera volcano was active, a large amount of granite was made under the western Japan which uplifted the mountains.
Because the Philippine Sea plate was blocked northward and the direction of its movement changed, East Japan started uplift by pushing from the Pacific plate westward three million years ago. The ocean floor from Hokkaido to Kanto became mountain ranges till the present. The northeastern and southwest parts of the Japanese archipelago moved toward the Pacific Ocean. East part of Japan moved in a clockwise direction, and East Japan rotated in a counterclockwise direction. The bent portion was pulled on both sides and settled, and it became Fossa Magna.
The Pacific plate subducted below East Japan, a trench extending from north to south was formed, and in parallel to it, wrinkles of earth in the north and south direction were formed. A series of outer arc uplift zones were formed on the land on the side of the trench, that is, a mountain range. A central lowland was formed on the west side of the mountains, further west side, a volcanic front and inner arc ridge were formed. The volcanic front is formed just above the magma where the Pacific plate sunk into the mantle and melted. Volcanic activities began several millions years ago and reached the peak in the period from 2 million years ago to one million years ago. Outer arc uplift zone consists of old Mesozoic rocks, volcanic front and inner arc ridge consists of igneous rocks from 23 million years ago to 5.3 million years ago.
Under the western Japan, the Philippine Sea plate subducts obliquely to form the Nankai Trough. This movement of the plate has made a huge lateral fault (Median Tectonic Line) at the part corresponding to the outer arc uplift zone. On the north side, the Seto Inland Sea exist, which corresponding to the central lowland, and further north side, the inner arc ridge and volcano front are formed and it reaches the Japan Sea. The volcano front is far from the Nankai Trough because the subduction angle of the Philippine Sea plate is shallow. Since the plate sinks diagonally, wrinkles of earth are obliquely formed in the outer arc uplift zone, and there are large peninsula and basins between them. Wrinkles of earth also occur in the central lowland, forming a large basin (Nobi Plain, Lake Biwa, Osaka plain) and several open sea in the Seto Inland Sea.
The current Japanese archipelago is located where the land masses on the Eurasia plate heading southeast collide with the Pacific plate moving towards the west. Meanwhile, the North American plate and the Philippine Sea plate are sandwiched. The North American Plate and the Pacific Plate are in contact with the Tohoku from the Kanto to the Pacific Ocean facing the Kuril Islands, forming the Japan Trench. The North American plate moves from the northeast direction to the southwest direction. Both the North American plate and the Eurasia plate have a land mass, and they do not fall inside the earth at the point where they hit. The boundary is a major fault zone called Fossa Magna which passes from Niigata prefecture, passes through Nagano Prefecture, goes to Shizuoka prefecture, Suruga bay.
On the east side of Fossa Magna, the Philippine Sea plate is subducting from the south. The islands of the Izu-Ogasawara arc, formed where the Pacific plate can get in under the Philippine Sea Plate, came to Japan on the Philippine Sea Plate at the position of the Izu Peninsula. The landed lumps of old ages were Tanzawa mountain clumps and the Izu peninsula. They had pushed the land to from winkles of earth such as the northern, central, southern Alps and Yatsugatake mountains. The area around the Kii peninsula is extruded in the southwest direction by the North American plate. The Boso Peninsula is at the intersection where the two plates are submerged. Thus, from Boso peninsula, two outer arc uplift zones are erecting and a huge central lowland (Kanto plain) is made. The reason the Kanto Plain did not become the sea was that a large amount of earth and sand was supplied from many rivers.
Hakone is volcanic area that has been active since 600,000 years ago. Fuji was formed by eruption several times from 100,000 years ago. The volcanic group of the spine of the Tohoku region and the volcano group of the San'in region started from several millions years ago and reached the peak in the period from 2 million years ago to one million years ago. Several volcanoes consisting of a huge caldera have erupted in Kyushu since one million years ago. In the southern Kyushu region, the topography from Mt. Aso to Kirishima to Kinkou Bay is a giant caldera assembly. Aira caldera on the north side of Kinkou Bay erupted about 30 thousand years ago. The most recent caldera eruption was the Kikai caldera in the southern part of the Kinkou bay, 7300 years ago. With this massive eruption, the living organisms in the southern Kyushu area have been extinct.
The anthropoidea of the old world appeared in the Africa continent then entered into the Eurasian Continent. The oldest fossil of an ancestor of a primate is about 65 million years old (late Cretaceous period). About 30 to 25 million years ago, the anthropoidea were divided into two groups, old world monkeys including Japanese monkeys and hominoids including apes and humans. Old world monkeys and hominoids live in groups. From the fossil record, the hominoids were prosperous at the beginning, but the proportion of the old world monkeys increased after about 10 million years ago. Currently nonhuman hominoids (ie apes) are on the verge of extinction.
In mammals in general, the main sense is olfaction, but in primates it changed to vision. For example, in mice, the odor receptor gene family has 1391 genes, of which 328 are pseudogenes. In human, there are 802 odor receptor genes, of which 415 are pseudogenes. In primates the opsin gene were duplicated and their sense of vision to red and orange became better. Communication between primates also changed from smell to vision. Besides primates, mothers and children recognize each other by smell. The vision became important and the expression of emotion was developed in the primates.
The primate's ancestor lived on the tree. The movement and tactile sense of hands in the primates developed and adapted to arboreal life. The thumb was placed opposedly to the rest of the fingers, which makes primates able to grasp. The muscles necessary for movement of fingers are also sensory devices of movement. Animals feel the extent of muscle's elongation and the contraction speed, so they inform their brain how much the finger is bent and how far the fingertip is spreading. Eyes of primates came to the front of the face. The visual information from the eyes passes through the brain, the command goes to the muscles to move the fingers, and prepare the fingers to move. A monkey instantly recognizes whether the grabbed branch is sufficient to support its weight or not, how about the deflection, and takes appropriate action. Brain and hand functions co-evolved.
Bipedal locomotion has been evolved in arboreal life. Orangutan seems to be a direct descendant of a monkey who walked two legs in arboreal life. In Africa the forest became a savanna and the grassland spread. Primates remained in a sparse forest (which cannot make a canopy), evolved into gorillas and chimpanzee, which moving up and down in the space in the forest. On the other hand, primates who live in savanna evolved into pithecanthropus (8-5 million year ago). Gorillas and chimpanzees changed from bipedal walking to knuckle walking, but the pithecanthropus did not do knuckle walking.
Upright bipedal walking and shrinking of cuspid teeth are characters separating apes from human beings. Some of the muscles necessary for upright bipedal walking are also necessary for arboreal living. Some researchers say that the bipedal walking evolved from ape-like knuckle walking, from the bone shape of the monkey's forearm. Among ancestors of arboreal living, apes appeared that happened to have pelvis suitable for bipedal walk. Such individuals were rather limited in behavior on the trees, but were advantageous for collecting activities on the ground.
There are some abilities and properties that are thought to have been acquired in the monkey era (incorporated as genes). Use of simple tools, group life, ranking in herds, skincare such as grooming in herds, fear of certain things. Chimpanzees use simple tools such as lifting ants, crushing hard tree fruits with stones. To use the tool, they need a skeleton that supports their muscles and hands, and a brain that controls harmonious behavior. In order to feed insects in underground and rotted trees, individuals who can control force with dexterous fingers were advantageous.
Phobia can be divided into four distinct categories. 1. Fear to animals such as snakes, spiders and scorpions. 2. Fear to the environment such as high places and dark places. 3. Fear to blood, corpses and injuries. 4. Fear to dangers such as being trapped in a small space. These were programmed to survive.
There are mainly two kinds of Hominina. One is a spindly type (homo genus) and another is a muscular type (Paranthropus genus). The Australopithcus has disappeared as fossils since the Paranthrhophus genus appeared around 2.5 million years ago.
The genus Paranthropus was larger and had hard grinding teeth compared to the genus Homo. Also, Paranthropus seems that the power of the jaw was strong as the cheek bone was developed. It was advantageous for ingesting hard plants with a lot of fiber. Fossils of the head of Paranthropus Robustus were found in the cave of Swartkrans in South Africa. Animal bones of 1.8 to 1.2 million years ago are also found in this cave. It is presumed that this cave is a living place of carnivorous animals where captured preys were drawn in and eaten. Heads of Paranthropus were left to become fossils, because they were hard to eat. Paranthropus coexisted for a while with Homo that appeared almost at the same time, but it was extinct about one million years ago.
It is thought that about 2 million years ago that the Homo genus, the current human strain, appeared. The fossils of the oldest original people were discovered from the stratum of 2.2 million years ago. Homo genus developed to the same size as the modern person. A mother gave birth to a child as immature state, which showed secondary late maturation that the brain develops even after birth.
The rewarding nerve affecting a wide range of the brain is called dopamine pathway. It extends from the midbrain as the base point to enter the hypothalamus. Here, the intensity of pleasure of appetite, sex will be determined by the amount of dopamine released by the nerve. Next it extends through the amygdala in the limbic system, some extend to the mesolimbic system, the rest reach the frontal association area. It is said that the dopamine pathway covers important parts for human mental activity, and human pleasure is brought about by the dopamine pathway.
Humans are born in the state needed the 100% protection from mothers. Although this is disadvantageous in survival, growth of the brain after birth produced plastic intellect and eventually succeeded in survival. If child's maturation took time, it seems that children's education became a joint work of men and women, and sexual bonds were fixed in the early history. In a slightly expanded interpretation, children's education has become more important as a group's collaborative work. In contrast to apes, the male would never fight over sex, sex would be privatized, and the group's cooperation system might have been enhanced.
Hominina evolved in Africa continent, but spread over Eurasia continent 1.8 million years ago. Homo erectus has also been found at the east end of the Eurasian Continent as Homo erectus pekinensis, Pithecanthropus erectus (Java) etc. However, it has not arrived in Japan. Perhaps there was no ability to cross the strait sea. Besides, a small human being of 1.8 million years ago was discovered in the Republic of Georgia and is called Homo erectus georgicus. The shocking finding is Homo floresiensis found in Flores Island in Indonesia. Its height was less than 1 meter and its brain volume was only 420 cc. Bones of from 90,000 to 18,000 years ago have been found.
Homo erectus can spread over Eurasian Continent thanks to rock salt scattered inside the continent. The way of salt is the rope of life. There is no human survival without it. The belt area of Northern latitude of 40 - 50 degree produced rock salt in Eurasian Continent. Homo erectus could not spread to cold regions such as Siberia.
Characteristics of Hominina are significant brain enlargement. Brain upsizing accelerated around 2-1 million years ago. The size difference between the macaque and human brain is 10 times. Considering the developmental process of the brain, if the proliferation period of the progenitor cells is longer by three days, the brain becomes 10 times larger. Human brain has more nerve connections than other mammals, so the brain becomes larger.
There is a possibility that 1-2 genes are responsible for enlarging the brain. Human brain enlargement is observed in the fetal stage. It is characteristic of humans that brain volume continues to grow until the late stage of fetal life. This is not seen in apes such as chimpanzees. Furthermore, in Homo sapiens, the brain grows after birth. The maximum brain volume before birth is determined by the size of the birth canal of the female or the opening of the pelvis. The newborn skull up to 400 cc can only pass it. The volume of 400 cc is the size of the skull of an adult chimpanzee.
Why did the human brain grow in size? The candidate gene is NOTCH2NL. The NOTCH family is a group of genes that induce differentiation during development. NOTCH2NL is a gene unique to humans by comparing the genomes of mice and chimpanzees with humans. 14 million years ago, A part of the NOTCH2 gene was copied to the long arm of chromosome 1 (ape type). However, this incomplete gene was repaired to become a functional NOTCH2NL gene 3-4 million years ago. After that, the NOTCH2NL gene was duplicated and increased to 3 genes. The NOTCH2NL gene is strongly expressed in the human fetal brain and also in the nervous tissue (organoid) made from iPS cells. Duplicate genes are evolutionarily unstable and are prone to deletions and duplications. Scientists are investigating whether hereditary neurological disorders are associated with the NOTCH2NL gene.
The larger brain needs a lot of energy. The cultural difference between the monkey and Hominina is the use of stoneware and carnivorousness. That is, crush the bones to eat bone marrow and brain, which other carnivores have left behind. Later Homonina used processed stone tools and left evidences using fire. Although there is the theory that enlargement of brains has come to eat meat, the carnivorous animals do not necessarily have big brains. It is thought that having a hand that can hold a tool promoted the development of the brain. Another hypothesis is that the genus Homo started using fire two million years ago and succeeded in nourishing the brain by ingesting carbohydrates and enlarging it. In any case, the graph of brain volume started up 2 million years ago.
In the past millions of years, the glacial period repeatedly arrived at a cycle of 40,000 to 100,000 years. Especially, the period of 100,000 years appeared predominantly since 800,000 years ago. The history of the climate cycle is preserved in the deep sea as sediments. It is also recorded in Antarctic glaciers in the past 200,000 years. The isotopes of various atoms in samples excavated from glacier of the Antarctica and rocks in the sediment are examined to determine the temperature of atmosphere. A commonly used isotope is the oxygen 18. Examining content of O18 in the sediment at the bottom of the ocean, it is cold if the ratio of concentration of O18 to that of O16 becomes higher, and it is warm when the ratio becomes lower. It is opposite in the case of the glacier. The amount of O18 relative to O16 contained in ice and snow increases as the temperature rises.
Mathematical analysis divides the cycle of isotope fluctuation into three kinds of waves, which are related to the fluctuation of orbits of the Earth. It is general that not only in the Earth, there are three elements in the planet orbit; eccentricity, inclination angle of the Earth axis, and precession movement.
Eccentricity is a numerical value that represents the extent of the ellipse of the Earth's orbit. The distance between the Earth and the Sun changes in accordance of eccentricity. The eccentricity variation has a period of about 400,000 years and about 100,000 years. The inclination angle of the earth's axis is the angle between the axis of the Earth and the orbital plane of the Earth, and varies from 24.5 degree to 22.1 degree with a period of 40,000 years. When the inclination angle is large, the solar radiation is strong in the summer and weakens in the winter, that is, the seasonal change increases. Precession is a swinging motion in which the tilted axis slowly rotates. I will make a lap in about 23,000 years. In half of the time, summer and winter will be reversed.
These changes only slightly vary in day time and angle of sunshine. However the changes in greenhouse gases (carbon dioxide, methane, etc.) due to biological activity, the albedo effect by glaciers (rearrangement of continents) result in enhancement by positive feedback to fluctuate the average temperature. The air composition in the glacial bubbles of Antarctica was examined on a large scale and it was shown that the concentrations of carbon dioxide and methane in the atmosphere correlate well with changes in temperature.
As the name suggests, the glacial age is the era when glaciers exist on land. As the glacier developed, water moved from the sea to the land. The coldest period of the ice ages is called the glacial period. The range of fluctuation of the temperature slightly increases since 500 thousand years ago, the glacial period tended to become longer. The last three glacial periods are the Mindel glacial period (300 to 230 thousand years ago), the Riss period (200 to 130 thousand years ago), and the Ulm glacial period (70 to 12 thousand years ago). Meanwhile, the sea level decreased by about 100 m. In the vicinity of the pole, the land where the living creatures were able to live becomes narrower, and the land increased near the equator. Also, it seems that the salinity concentration rose by the amount of seawater less. For terrestrial organisms, temperature and vegetation may have been promoting species differentiation due to the relatively short period variation, as the same, salt concentration may have been for marine organisms.
The temperature variation graph shows that the present age is the interglacial period. The present warm interglacial period ends at most 10,000 years, after which the glacial period arrives of about 70 thousand years.
In the classification, the genus is above the species, and the family is, then, the order. There are 180-200 species (so-called monkeys) in the order of primates. Among them, there is only one species of Homo sapiens in the family Homo. Obviously, it is abnormal. Only the homo sapience cannot have made any special evolution exceptionally in the family. Like in other families, many genera and species were born, but it is thought that everything was destroyed.
The nature of departing from home and to the world seems to be a feature of humanity. Apes survive in the fixed place of the jungle and will not move to look for new habitats. Hominina who left Africa more than 1.8 million years ago immigrated to Eurasia continent promptly, from Flores Island (Indonesia) at far East to Spain at far West, where is tropical or Mediterranean climate. From a few fossils and archaeological evidence, Hominina lived primarily in a temperate climate. It was exceptionally only warmer period that the Hominina went beyond 45 degree line of the north latitude.
Homo erectus was born in Africa 1.9 million years ago and left Africa to enter Asia. They reached Java 1.6 million years ago, which was connected to Asia. It was extinct 500,000 years ago in Africa and Asia. However, they lived on Java until 100,000 years ago.
Recent discoveries have found other humans, other than Homo erectus in Southeast Asia. Small human Floresiensis found on the island of Flores, Indonesia. H. luzonensis was also found on Luzon Island in the Philippines. Floresiensis had survived till 20 thousand years ago, but it is thought to be Hominina from the structure of the wrist bone. Height is 1 meter, brain volume is only 400 cc, it is a size of Australopithecus. Therefore, the assumption collapses that the brain upsizing occurred in cooperation with the evolution of human beings, that is, the use of tools and sociality. There is a genetic disease called Microcephalic osteodysplastic primordial dwarfism type II. It is a mutation of the gene PCNT. Human being with this mutation has a small body and brain. Is Floresiensis a progressive Hominina with this genetic mutation?
The melanocortin receptor gene controls the proportion of melanin pigment in skin, which determines the color of the skin of hominina. When examining the silent mutation in the melanocortin receptor gene in current black peoples and applying it to the gene clock, it was fixed 1.2 million years ago. Melanocortin receptor gene mutation is thought to have spread over 120,000 years ago, that is, throughout the Hominina. Did the color of the black skin be chosen because their hairs became thin? Analysis is awaited of genes involved in dwarfing of body hair. On the contrary, the invention of clothes overcomes the temperate of freezing winter and became the basic technology crossing the glacier.
Traces of human beings using fire trace were found back to the Middle East of 790,000 years ago. Homonina used fire first. After this, traces of fire use were discovered about 500,000 years ago in China and about 400,000 years ago in Europe. To use fire is to have technology to control fire. There should have been knowledge and tools to obtain and maintain fire. The method of using fire that hominina invented was handed down to Neanderthals and modern people.
To use fire has various merits. Heating, cooking, light and weapon. Human beings could expand their settlements around the world due to the use of fire. There is the winter even in temperate areas. Fire would provide men a heating system to get over the winter. The technique to withstand the cold was also a technique that crossed over a highland which is a cold district. Furthermore, when heated, all microorganisms, such as bacteria, die. When boiling or baking, hard food also softens. In addition, it was heated to eat hard fruits and dried meat with high storability. Many foods found in unknown places could be edible by heating. It is unknown how the hominina got the fire.
Mankind has acquired digestible food by using fire. Their internal organs had shrunk and the energy used by internal organs had become to use for the brain. Human brain grows slower than brains of other mammals. The maturation of the body is also slow. There is a theory that body growth has been sacrificed in order to develop a brain with high energy consumption.
In the ruins of Grand Dolina 780 thousand years ago, evidences of cannibalism are found. In addition, the outrage is a routine matter in an undeveloped society. In a typical undeveloped society, 80% of tribes perform tribal conflicts more than once a year, and the deaths from battles are one in 200 every year. Moreover, there are many extermination fights. For early hominina, cannibalism may have even been a valuable source of food. In East Africa, a cradle of human beings, several species of Australopithecus and Hominia were inhabited together. I cannot think that they had mutual consciousness as a human being.
Human being closer to modern people appeared among Hominina remaining in Africa. Neanderthal people are famous. Genomic DNA was analyzed from the Neanderthal fossil bone, and at least 99.5% of the genome were found to be identical between the current human being and the Neanderthal. They branched about 706,000 to 330,000 years ago from the ancestor of the present human race.
The Neanderthal people have slightly larger brain volumes than the current human beings, and the skeletons are almost the same. They produced a new stoneware technology. The Neanderthals are said to have lived in Europe and West Asia, but recently their fossils have been found in Uzbekistan and southern Siberia. A mixing between the ancestors of the present human race and the Neanderthal surely occurs, and a part of the Neanderthal genome sequences are found in the modern human genome. Modern people settled in Europe 45 thousand years ago. Analysis of 51 genomic DNAs from 7000 to 45000 years ago showed that the Neanderthal DNA in the genome decreased from 3 to 6% to 2% during this period. The Neanderthal people disappeared from the fossil record about 30,000 years ago.
Analysis of the hyoid bone of the Neanderthal people discovered from the Kebara cave in Israel suggests that the Neanderthals had the same speaking ability as us. The hyoid bone is a potential role in speaking and its position is adjusted by 12 muscles. The Broca’s area, which is the center of speech, is probably well-developed as estimated from Neanderthal brain volume. Between Neanderthal's DNA and current human beings have the same version of "language gene" called FoxP2. It seems that the Neanderthal people could talk with each other.
The genomic base sequence of an old woman excavated at the Denisova cave in the southern part of Siberia was examined using DNA extracted from the finger bones of the hand. From the shape of one tooth, Denisovan was suggested to be evolutionarily different from both Neanderthal and present human beings. The group to which the Denisova woman belonged has the same origin as Neanderthal. It is estimated that the Denisovan and Neanderthal ancestors diverged from today's humans 800,000 years ago. After that, the two humans separated, but the time is unknown. The characteristic base sequences of the Denisovans remains in humankind today and is found in the natives living from Siberia to Oceania. Mixed-race bones of Denisovans and Neanderthals have also been found.
The Denisova Cave was discovered in 2010 and is located at the foot of the Altai Mountains, the boundary of four countries, Russia, Mongolia, China and Kazakhstan. Humans began to live in the Denisova Cave 300,000 years ago, and judging from the stone tools, they were Denisovans or Neanderthals, and from 200,000 to 55,000 years ago, the cave was mainly used by the Denisovans. During this time, it seems that Neanderthals lived together 190,000-100,000 years ago.
Not only did mankind come out of Africa, there should also be a return group. In particular, the Middle East is the area of intersection of the going-out and the returning human beings. There is expected direct crosses and diverse cultural interactions. Genes from Neanderthals can be found in the African genome. There is no evidence that a new human race was born on the Eurasian continent. If it is all African origin, there will be some reason.
The direct ancestor of the modern human, Homo sapiens, was born in the Riss glacial period (200 to 130 thousand years ago). The birthplace was in Africa continent. In the glacial period, the tropical regions of Africa are thought to be dry. The tropical rainforest shrunk and was surrounded by spacious savanna. The desert expanded.
Naked modern human beings were unable to leave Africa for tens of thousands of years, during the Riss glacial period. Meanwhile, the modern human being was able to develop and maintain advanced technology compared to the other human being. Present human race invented polished stone tools. They also developed heavy stone instruments (such as axes) with fine workmanship, in consideration of stone quality. When they started agriculture, they developed stone sickles for harvesting grains, stone dishes, stone bowls, stone pestle for milling, and stone arrowhead etc.
The stoneware developed by the present human race is designed according to the application. They also used bones and ivory in combination. Perhaps they would have changed the design of the tool to match the ecosystem (such as prey animals and plants are, the geographical conditions of the hunt).
A phylogenetic tree based on mitochondrial DNA of modern people, one of the African branches is corresponding to other races, such Caucasian and Asian. When chimpanzee's DNA sequence is added as a reference to this phylogenetic tree, assumed that human and chimpanzee branched five millions years ago, the common ancestor of the modern human beings is calculated to be about 200,000 years ago. Because the phylogenetic trees are made with the hypothesis of "branching", this alone is not enough for evidence of the time of birth. After Homo sapiens idaltu (about 160 thousand years ago) with quite similar characteristics to the current human race was found in Ethiopia, and "African single origin theory" was almost confirmed.
Evidence was discovered that ancester of modern human used coastal resources at the Sea cave near the Pinnacle Point in South Africa. It is 164,000 years ago. In South Africa there are archeological sites of Brombos cave and caves of the Klasies River. Bone tools were found to process leather goods. For the decoration of the body, they used a red paint or carved a geometric pattern using bone tools. They also used fire on a small fire pit, and hunted various animals and fish. They lived near the sea and can prosper by use of sea food, especially shellfish as a revolutionary food. In the hunting and harvesting society, shellfish is easy to collect and provided high quality protein to mankind. Perhaps women's contribution has been enhanced to food security.
It is unclear which is the hometown of modern people, Ethiopia or South Africa. Both are possible, but there may be another possibility.
Africa suffered from droughts from 135,000 to 90,000 years ago. Human being experienced a severe bottleneck. Probably it decreased to about 2000 people. From the analysis of genomic DNA, it was then expected that as many as 40 populations were scattered on the African continent. 74,000 years ago, the Toba eruption in Sumatra make human being experience a bottleneck again, and about 60,000 years ago, two small groups began great migration.
In the group hunting for a group of large mammals, it was necessary to consult in advance about how to catch prey and the target animal to catch. Hunting for large animals is dangerous, but fruits are so great. It can provide much food to live for a long period of time for a group of human beings. It can provide fur to surpass the cold and a lot of hard bones that are easy to process. The co-conspiracy is thought to develop their logical form of the language. Words or abstract gestures like words were used, sometimes pictures and figures are drawn on the ground. The words were arranged to clarify causal relationship, to have logics, the spatial position and time.
For the ability to speak a language, various factors are involved. The function to understand and produce languages is thought to be Broca's area or Wernicke's area of the cerebral cortex. Both areas were born in the Hominina. The nervous system related to motor control of vocalization has changed markedly in the course of human evolution.
Anatomically speaking, vocalization involves the jaw, tongue, laryngeal organ, and head muscles. It is the muscles that control the vocal organs. They move in cooperation to create various phonemes. The rich vocalization of human beings should have developed the set of muscles of the head and the nervous system governing it. The area that controls head muscles is next to the area that controls the hand in the cerebral cortex. Possibly, the two regions might have developed in relation to each other.
In mammals, control of movement of the jaw, tongue, and laryngeal organ is performed by the premotor reticular formation. Cerebral cortex directs the premotor reticular formation. That is, the cerebral cortex controls the vocalization indirectly. The nerve extends from the premotor reticular formation to the trigeminal nucleus, the sublingual nucleus, and the pseudo nucleus. Each nucleus controls muscle movement of jaw, tongue and laryngeal organs. That is, control is near the periphery.
In nonhuman primates, the cerebral cortex for vocalization directly dominates the trigeminal nucleus and the sublingual nucleus. Direct control of the cerebral cortex also extends to the movement of hands and fingers. That is, motion commands in the cerebrum are reflected directly in the motion of the fingers.
Direct control of the cerebral cortex has developed further in humans, and the respiratory system and visceral motor nucleus are also under its control. Vocalization involves the jaw, tongue, laryngeal organ, and all breathing exercise. By controlling these movements directly by the cerebral cortex, we made possible complicated and agile vocalization. This means we can learn the control.
FoxP2 was reported in 2001 as an essential gene for the ability of conversation. It was found as a mutated gene in a family with a defect in conversation. FoxP2 is a transcription factor. The person with FoxP2 gene deficiency cannot understand such as the regularity of the sequence of the sounds in the conversation, the information of the context or the relationship with the action.
Mice lacking this gene cannot produce crying of ultrasound to attract opposite sex. Sonar of the bat is related to the function of this gene. Inhibition of this gene in Zebra finch decreased their learning ability of the song and their stability of the song. Apes also have one change in nucleotide sequence that occurred five million years ago.
It took a long time before the language system was born. First of all, we distinguished things by giving an individual name, such as to fruits, small animals, and fish. Next, words were born to indicate the location, time, how to eat, differences from similar poisoned items. Then, taking the tool as an example, the meaning as a material of the tool, its strength, its weight, ease of processing, how to use it, and more, effective usage. Words were refined during communicating among generations, and were arranged as a language. The brain already had enough capacity to store the much information. Individuals with excellent linguistic ability were also advantageous in terms of evolution. I believe that this selection is still continuing.
85,000 - 50,000 years ago: Modern human was born in Africa 200,000 years ago, and reached Eurasia after a period of time. The dairy life of modern human beings was a little better than other human beings during from 200,000 to 50,000 years ago, judging from the tools such as stone tools. The ancestry of humankind actively started to move to the Middle East about 85,000 years ago, and spread to all over the world.
It is calculated that the size of gene pool would be 5,000 of the modern human at the beginning in 200,000 years ago. The human race seems to have advanced from Africa to the Middle East 125,000 - 90,000 years ago in the final interglacial period (Riss-Wurm interglacial period). It seems that the human race who left Africa collided with the Neanderthal people who lived in the Middle East. Entering the Last Glacial Period (Ulm Ice Period), the Sahara Desert was expanding. Modern human being was expelled from the green belt left near Ethiopia so their movement was acivated. Mankind's advance into the Middle East was more than once. In addition, there are various routes to advance, such as via the Sinai Peninsula and the Arabian Peninsula. It is likely that they went north along the coast. The Red Sea was a sea dotted with islets during the Ice Age. It is estimated that the gene pool when entering the Eurasia continent is about 500,000 people in 70,000 years ago.
At that time, it is estimated that there were huge continuous deserts in the Arabian Peninsula, the Middle East, Iran, and Central Asia. Furthermore, the desert was connected to the tundra desert in Northeast Asia. The spread of mankind has taken a path around the edge of this desert. Mankind mated Neanderthals in the process of expanding into Europe and Denisovans during expanding into Southeast Asia.
The Toba volcano on Sumatra Island erupted about 74,000 years ago. It temporarily lowered the temperature of the Earth so that mankind faced to be endangered. In particular, since the continent of India was covered with thick volcanic ash, mankind should have been near extinct if arrived.
Modern people advanced into cold weather by devising a hooded clothe with cold weather-proof. In the glacial period, Siberia was not covered with forest (Taiga) but grassland. Large mammals such as mammoth lived. The hunting prey was large, enough food was obtained by one hunting, and the cold climate was suitable for preserving raw meat and other foods. There are two subspecies in the lice parasitizing and sucking blood: the head lice in the head and the body lice in the clothes. It is thought that the body lice have diverged from head lice, since human began to wear clothes. As a result of comparing the genes of both lice, the branch was calculated to be about 72,000 years ago.
Our ancestor arrived approximately 66,000 years ago at India around the Arabian Sea, which was relatively greening. Analysis of genetic variations on 132 individuals from 25 different groups of Indians revealed that two genetically different ancient populations are the ancestors of the current Indians. One of them, the group named Ancestral North Indian, is genetically related to Middle Easterners, Central Asians, and Europeans. The other line, the Ancestral South Indian, has no population close to the Indian subcontinent. Negrito ethnic minorities living in the Andaman archipelago were isolated from the south Indian population in ancient times.
The human race divided into two from India. One is to enter Central Asia, and spread from Siberia to the Americas. It was a race adapted to cooling. One subgroup heading from the central Asia to the west advanced to Europe. It is thought that this expansion was a battle with the Neanderthal. In Europe, the latitude is high and the amount of ultraviolet ray decreases. If the skin is black, human being cannot make enough vitamin D. Vitamin D is essential for calcium metabolism, skeletal abnormalities appear (rickets) if it is deficient. White skin was essential for spreading in Europe. Change to white skin occurred twice, one in Neanderthal, other is in modern human.
The other route was to advance to Southeast Asia. Although it was the glacier period, a horizontal movement near the equator did not take long time to advance. In the Wurm glacial period, the sea level declined, Sumatra, Java, Kalimantan (Borneo) islands connected with the Malay Peninsula, the surrounding continental shelves also landed, collectively, formed the Sunda continent. The Sunda continent was adjacent to the Sahul continent composed of Australia and Papua Island and its surrounding continental shelf. There were narrow straits between the two continents. Modern human expanded by tracing the seaside, which provided similar natural environment. Provably, this spread was rapid due to applying the hunting and sampling technique once established at the beach.
50,000 - 20,000 years ago (1): Human being had been producing tools led to modern technology from 50,000 years ago. The climate is corresponding to Wurm glaciation. Human beings lived with mainly gathering and hunting, by having developed various tools and adapted to various environments.
As shown by figures and decorations at the ruins of South Africa fifty thousand years ago, human being has clearly an ingenuity since this time. At the latest at 25,000 years ago, human beings have expressed and presented various relationships between individuals, or individuals and groups, by art expressed in tools. The needles and threads invented 30,000 years ago helped lives in cold circumstance. They made a rope from threads. A bow has been invented 20,000 years ago.
As humanity expanded the area of accommodation, large herbivorous mammals also died out. Especially in the Americas and the Australian continent, about 80% of these animals were extinct compared with the species found in fossils. Elephants remaining in South Asia and sub-Saharan Africa survive, escaping the tragedy of fellow mammoths and mastodons. In Africa, since elephants and large herbivores of grasslands survive, hunting in group is considered to belong to ability of human being who reached to Asia. Especially, groups immigrated to Australia and the Americas, who had advanced hunting technique, did hunt them effectively.
There were evidences that 23,000 years ago human being collected grain seeds. Because of ruins using a furnace by old human being, they are considered to be a semi-settlement life. Also, evidence of baking bread was found from the furnace 14,000 years ago. In order to make bread, techniques are needed such as threshing and grinding grains.
The oldest painting of mankind was found in a cave on the island of Slavesi, Indonesia. It is a picture of a pig, a small buffalo, and Anoa, estimated to have been painted 40,000 years ago, when humans arrived in Indonesia. The first European cave paintings discovered were 14000-21000 years old. 40,000 years ago. In addition to animals, the painting depicts a half-beast man with protruding a nose and a tail, and there was also a figure hunting anoa. It is presumed that human beings at that time had myths and metaphors of the supernatural.
Mutation of the microcephalin gene (MCPH1) involved in frontal lobe development dominated 37,000 years ago (between 14,000 and 60,000 years ago). It probably affected human culture afterwards, especially language formation. Mutation occurred somewhere from Africa to India because this mutation is not detected in human beings in the south of the Sahara. In fact, there are 1800 genes that have recently been mutated. Mutations in these genes are thought to have been naturally selected with the civilization of humankind.
There are not many measurable points showing the sea level of the mid Wurm glaciation period, but 35,000 years ago, the sea level seems to be 60-80 m lower than the present. A sharp drop about 40 m in sea level occurred around 31,000 years ago. In other words, rapid development of glaciers occurred in the northern hemisphere. It is estimated that 26,500 - 19,000 years ago the sea level decreased by about 125-135 m from now. Over the next 10,000 years, the glacier developed and the sea level remained much lower. The sea level declined rapidly by 20 m from 22,000 years ago in 500 years. Rapid warming started 19,000 years ago and the glacier melted. It became the interglacial period.
The origin of agriculture is unknown. I think that the trace of the agriculture is on the current continental shelf, and everything submerged. However, agricultural technology could have been spread even in the middle area of the river and in areas not submerged, but no evidence is found. According to Greenland's ice core data, in the glaciation age, cold and dryness fluctuated greatly with a cycle of several years. Nobody could expect the harvest of the year where they made the field. That is why people chose a moving life, looking for food that was easy to get at that year. After entering the interglacial age there was little fluctuation in the temperature, so human beings were able to start agriculture.
50,000 - 20,000 years ago (2): Mankind who left Africa before 85,000 years went the East along the coast and the river. They moved inland from India and Anatolia. By 20,000 years ago, human beings expanded their habitat to southern Europe, East Asia, high latitude regions, and Australia.
A modern human being expanded from India to Central Asia along the Indus River. They headed the West and entered Bulgaria near 50,000 years ago. The whitening proceeded as it advanced to Europe. From the analysis of mitochondrial genes, it is presumed that they had entered Europe as a group several times before 15,000 years ago. Modern Europeans are considered descendants of the people who emigrated these days. The group who moved to Europe got body features as a Caucasian, high stature, white skin, high nose, and colorless hair and eyes.
There are groups emigrated from Central Asia to Southern Pacific via Siberia. Analysis of mitochondrial DNA suggests that the indigenous American people's ancestors were those who lived in Siberia. They also have mitochondrial mutations adapted for cooling.
The prosperous group on the Sunda continent formed a race as Mongoloid. The body features of Mongoloid are like Neoteny (short arms, legs and a relatively large head) and pale skin color. Yellow skin Mongoloid is considered to have expanded northerly in the final glacial period and mixed with a group migrating from Siberia to the East. Genes that have lost the skin color of Mongoloid have not been identified yet. Mongoloid has moved from Southeast Asia into South China and India.
There were human race groups emigrating northward from the Sunda Continent. They went north along the arcuate archipelago located near the coast of China and the Philippines. Utilizing ocean current, they moved along the arcuate island from South China Sea northward, then arrived in Japan. Human beings migrated from the coast to inland areas along the river basin of the Mekong River, Yangtze River, or Yellow River. Since these large rivers are flowing from the Tibetan Plateau, human being have lived in the Tibetan Plateau early age. They could move to Alaska along the arcuate archipelago, but there is no evidence. It should have been mixed with a group from Siberia to East Asia.
Modern Human reached Australia about 47,000 years ago. When mankind landed in Australia, the sea level was not so low, so that humans would have crossed the continent of Australia (Sahl Continent) by ship. That is, there was group who invented ships while moving South Asia to the East. Indigenous Australian, Aboriginal has a black body color, seems to inherit the characteristics of the African ancestors as they are.
20,000 - 15,000 years ago (1): The Earth entered a period of great freezing. North America, Siberia, Europe were covered with glaciers. The sea level decreased by 150 m from now, and the continental shelf expanded. The climate has reversed in 19,000 years ago and the rapid warming started.
Evidences of art have been discovered in Europe for about 50,000 years ago, but especially at this time, human being elaborated fine cave paintings. Lascaux is drawn at 15,000 years ago, Altamira is a ruin of 18,000-10,000 years ago. The origin of the Great Eurasian language family proposed by Dr. Greenberg dates back 15,000 years ago. The Indo-European language family, a big branch, is said to have been established 8,000 years ago.
In the Wurm glacial period, it was coldest about 19,000 years ago. Temperature was 6 degree lower at the average than now. The ice sheet went the most south and the land above 50 degrees north (North America, Canada, the Scandinavian Peninsula, Siberia) is covered with ice sheets and Greenland and North America were connected by ice sheets. There are large rivers flowing into the Arctic Ocean in Siberia now, but they were stopped by the ice sheet and a huge glacial lake appeared. Europe was covered with glaciers to England and the Baltic Sea.
The volume of the ice sheet is estimated to be three times the current ice sheet in Antarctica and Greenland. As the water was on land as ice, the sea level declined. It is estimated that when the glacier was the largest it was 150 m lower than the current sea level.
Inland parts dried. Of the land between 30 degree both North and South latitude, the area of the desert is about 10% now, but before 19,000 years ago, it reached 50%. In particular, they were distributed in two belt-like shapes centered around both 20 degree North and South latitude, and sand dunes developed in North Africa, South Africa and Australia. For this reason, the human race remaining in Africa is divided into three groups in the north, the south and the equator, there is a possibility that the genetic difference became larger among them.
The yellow sand has been brought from the desert inland China. Examining the yellow sand, in addition to deserts distributed in mid-latitudes such as Takla Makan and Gobi, it also flew from the northern Asian continent such as northeastern China, Mongolia, Siberia widely from about 75,000 to 10,000 years ago. It is thought that the desert had spread in the central Asian continent of the last glacial period.
20,000-15,000 years ago (2): There is a vast continental shelf on the sea side of the area where an ancient civilization appeared. The history of ancient civilization before its birth may have been developed on the submerged continental shelf. In addition, ancient civilization appeared around 30 degrees north latitude, where crustal movements are severe due to continental collisions.
It is thought that the continental shelf was coastal plain during the ice ages. The average depth of the continental shelf is approximately 130 m and the width is 78 km on average. It reaches about 10% of the ocean area. This land was given to our ancestors in exchange for the ice sheet and the desert. From the distribution of continental shelf, we can infer the distribution of human beings 19,000 years ago.
First, Persian Gulf. The Tigris / Euphrates's large river would have been one and would have given moisture to the valley of the Persian Gulf. The shelf off Bombay in India and Bengal Bay provided pretty large plains. Human beings left for Central Asia from here.
The Red Sea and the Mediterranean Sea became inland Sea. The Mediterranean was divided into two by the Italian Peninsula, and the Aegean Sea became a plain where the island and the lakes entwined. The human race in Europe ran down south of the Mediterranean coast according to the expansion of the ice sheet. The vicinity of the UK became a vast plain. The Baltic Sea became a frozen, wide valley. The European plains were high in latitude and cold, so population density was low. The water overflowing from the lake of Siberia flows as a river from the Caspian Sea to the Black Sea, on the other hand, also poured into the Baltic Sea.
Many human beings lived in the Sunda and Sahl continents, centered in Southeast Asia. In East Asia, there was a large continental shelf now called the East China Sea. It was a relatively temperate even during the ice ages. Also, as a result of the distribution of many islands, the human race might have developed greatly here. The Sahl continent was so closer to the Solomon Islands (which was one island) that human being could go by ship.
Northward from the Sunda continent, there was a land from the Philippines through Taiwan, so the South China Sea may have been inland sea or a lake. The East China Sea became land, where Yellow River and Yangtze River gave moisture. Were the two big rivers joining one? Its estuary will be around Okinawa. The northeast area where human beings could live might be Hokkaido island. In Okinawa island, the oldest human bones were found in 2007, estimated to be 20,000 years ago. In the case of the Japanese archipelago, global warming preceded about 3,000 years because there were no huge ice sheets like in Europe and North America. Earthenware was invented in this area at around those era
The Sakhalin and the Syria are inland. The Kuril Islands divided the Okhotsk Sea from the Pacific Ocean. The Aleutian Islands surrounded the Bering Sea with the Bering Cross Bridge. This area is called Beringia. Beringia is the third largest in the submerged continent.
The Gulf of Mexico and the Caribbean sea became the inland Sea, but the human race would have not yet reached.
15,000 - 10,000 years ago: The Earth became warm and glaciers melted. Especially the destruction of a huge glacial lake caused the sea level to rise all at once, so human beings had to move to inland from the coastal plain. As heavy thicker glaciers pushed the crust down, Scandinavian peninsula and Canada are still rising now.
Glacier melted gradually due to global warming. As the continent was tilted towards the Arctic Ocean, water was caught by glaciers to form a huge lake. The glacial lake broke down and a large amount of pure water flowed into the vicinity of the Arctic Ocean. This caused oceanic floods. It is estimated that the oceanic flood happened 3 times (about 14,000 years ago in the first time, about 12,000 years ago in the second time, 8,000 years ago in the third time). Sea level rose rapidly about 10 m by one marine flood. The flood hit the coastal plain. This 10 m rise of sea level at a time was enough to destroy the human culture which had spread to the beach.
Among the three, the most famous one is the marine flood of the Younger Dryas cooling of 12,000 years ago. The lake of Siberia reached the Arctic Ocean, and a lake of North America flowed out, the Arctic Ocean and the North Atlantic Ocean were considerably desalinated. As a result, the deep-sea circulation stopped that sea water had been submerged from the North Atlantic into the deep sea. The warm Gulf of Mexico Current ceased, which had been flowing northward in the Atlantic Ocean. Temporary cold season hit Europe and North America. During the cold season, human being developed agriculture in the Middle East and Mesopotamia region. The population 12,000 years ago when agriculture began was about 5 million.
During the cold season, humans developed agriculture in the Mesopotamia and the Middle East. As the ice sheet receded, forests expanded again and deserts shrank. In Levant region, wild wheat, rye and barley were overgrowing, and a group called the Natufs established the first settled society. The cooling of Younger Dryas struck them when the population increased due to rapid warming.
Here are my guesses of the main areas that were submerged and the new destinations of human beings living there.
People who lived in the Mediterranean East Coast Plain went back along the Nile river and founded the Egyptian civilization. Other of them moved to the Aegean Sea, Anatolia. People who lived in the coastal plain of the Persian Gulf migrated to Iraq along Tigris and Euphrates River, and built a Mesopotamian civilization. In the Middle
People who lived in the coastal plain of the west of the Indian continent migrated along the Indus River and built the Indus civilization. People who lived in Sunda moved diversely as the sea level rose. West to Indochina peninsula, East to Polynesia, North to China, Japan and Korea. People who lived in the coastal plain of the East China Sea migrated northward along the Yellow River and the Yangtze River. The first cereal (rice) cultivation was made about 15,000 years ago is the Yangtze civilization.
Families who moved to Siberia lived in south region of the glacier. The candidates are in the coast of the Japan Sea and the Okhotsk Sea, where had become inland sea. Also, Mongoloid adapted to the cold climate had lived in the southern side of a huge glacial lake. Along with global warming, glacier lake moved to the north, and they may have moved north along with the lakes. After the glacial lake broke down and disappeared, they may have moved to the Americas across the Bering crossover. The Bering crossover was accessible from 14,000 years ago to 11,000 years ago. When the Bering Strait landed, the Kuroshio current should have flowed towards the North American continent in a substantially horizontal direction. There are records that Japanese fishermen in the Edo era were flowed to the Aleutian archipelago. In the past, some of the people can get in the ocean current and can migrate from Aleutian Islands to North America.
The first culture in the Americas is Clovis culture which makes spears with characteristic stoneware around 11,500 years ago. When they first appeared in the Midwestern part of North America, they spread quickly throughout the North American continent and then expanded to Tierra del Fuego at the southernmost point in South America only in 1000 years.
Around this time, Jomon pottery was made in Japan (bean grain pottery found in Senpukuji Cave, Setogoe-cho, Sasebo City (12,000 years ago)). With the addition of earthenware, the meal changed completely. Until then, raw vegetable and meat were barbecued on stones. The staple food has been replaced by preservable starch-based foods such as walnuts, chestnuts, acorns, and grains. Animal meat became rare, with the addition of fish and shellfish. The distribution of various precious stones in the Jomon period was about 200 km from the production area. This distance was within the scope of logistics, politics, mutual understanding, etc.
Dogs were domesticated in East Asia 15,000 years ago. Dogs are rare animals that have a strong sense of belonging to a group and can grasp human facial expressions. It was useful as a watchman in the hunting life.
10,000 - 8,000 years ago: The Earth warmed rapidly and the sea level rose. Agricultural technology was discovered all over the world. Human beings have developed agriculture and spread to various places along with the language.
Agriculture is said to have started in a fertile triangle 10,000 years ago, but occurred around the world almost at the same time. It is estimated ten independent areas that agriculture started in the world. In China, rice farming started 8,000 years ago. There are ruins of rice field, where people pulled water and irrigated. Pumpkin was cultivated in the America continent 10,000 years ago, corn was 9,000 - 8,000 years ago, peanuts 8,500 years ago. In New Guinea, agriculture of banana, taro and yam potato started 7,000 years ago. As the temperate climate had continued, the people who settled and began agriculture became relatively rich.
There are 200,000 kinds of angiosperms that makes flowers bloom and seeds, but there are only thousands of edible plants. Among them, there are hundreds of things economically possible for cultivation. Currently, only 80% of agricultural crops consumed in the world in one year are a dozen or two cereals, beans, root vegetables, vegetables, and fruits. These main plants have been cultivated for thousands of years. Only five species are domesticated in mammals as major ones. Such as sheep, goats, cows, pigs, horses only. There are camels, donkeys, alpacas and buffaloes, but the environment is limited that they can be bred, and also the areas that humans use them for food or for production.
Livestock seems to have established at about the same time as the establishment of agriculture. Livestock has the great advantage that meat can be obtained without hunting. Since 10,000 years ago, sheep have been domesticated in the Taurus Mountains and goats in the Zagros Mountains in Levant. At the same time, cattle were domesticated from the wild Aurochs in the Near East and India. Pigs were 10,000-9000 years ago in Asia and Europe. Chickens were in South Asia 8000 years ago. 8000 years ago, Mongolian horses were domesticated in the central grasslands of Eurasia. Llama was 5000 years ago in the Andes in the Southern America. Turkey was 3000 years ago in Mexico.
The use of "secondary" products such as milk, hair, traction force which obtained without killing livestocks were one important advance in agricultural development. Analysis of the organic residue of more than 2,200 pottery excavated from the Middle East to the Balkan Peninsula estimated the first use of milk 9,000 years ago. The use of milk was particularly important in the present Northwest Turkey, and the environmental conditions in this area were considered particularly suitable for cattle. 15,000 years ago, dogs were domesticated in East Asia. According to the analysis result of the gene, it was estimated that the cat separated from the wild cat in the Middle East 100,000 years ago. It seems that it was domesticated by humans kept in the Middle East since 9,000 - 10,000 years ago.
Traditional hunters kept living as they were in mountainous areas, forests, coastal areas where agriculture cannot be done.
Clams were cultivated in the Salish Sea in eastern Canada 9000 years ago. When the size of the fossil clams was examined, the size of the shellfish was larger than before 11,500 to 10,000 years ago. Humans, who arrived 9,000 years ago, began farming clams, and 5,000 years ago they were developing shellfish farming technology. The ledges of the shallow sea were surrounded by walls to protect the shellfish from predators such as fish and crabs, and to feed plankton and mollusk meat.
The Indo-European language family originated from the Anatolian Plateau of Turkey and began spreading about 9,000 years ago. The geographical distribution of the language, the time when farming started in that area, and the distance of closely related relation of language are correlated. The people living there are not descendants conquerors who conveyed farming techniques and the Indo-European language. Only agricultural skills and language were conveyed. People with excellent technology introduced languages with technology, to those who learned actively the language. Grains can be preserved for a long time, so wealth can be preserved. Agricultural culture with grain as a staple food has developed greatly.
8,000 - 6,000 years ago: The Earth was warmed towards the Hypsithermal period, and the climate became warmer globally than in the present age. A prototype of the walled city was built. People with white skin appeared with a mutation.
During the Hypsithermal interval, the area from North Africa, India, to East Asia became wet climate. In particular, the current Sahara desert had become extremely moist, and large vegetation had spread inside it. Sea level rose around the world 5,000 - 7,000 years ago when global warming peaked. It is thought that half of the Kanto Plain was covered by the ocean deduced from the distribution of kitchen middens (Jomon/Flandrian transgression).
As the sea level rose, a large amount of water flowed into the Black Sea through the narrow Bosporus Strait from the Mediterranean Sea. Perhaps the Black Sea coast would had been hit by a gigantic flood. In the sea bed of the Black Sea, a trace of a large amount of water flowing about 7,600 years ago, that is, canyons were discovered. The Great Flood of Noah, the Great Flood of Gilgamesh epic poems may have been handed down a major incident at this time. In addition, the shallow Bosporus Strait may have been made over land bridges several times due to climate change. Moses' miracle of breaking the ocean may have actually happened. Similar incidents would have taken place all over the world.
The oldest ruin of the walled city was Jericho of Jordan 8,000 years ago. Rectangular buildings using sun-dried bricks were preferred. Storage facilities and bread kilns were also provided. Buildings are interpreted to be used for defense or religious facilities. There are also large-scale residences in the vicinity 11,000 years ago. People have lived in Jericho since ancient times and have built a rich culture that makes cities.
In the ancient Orient, the use of earthenware was from relatively old, about 7,000 years ago. Earthenware was first made with sunburn, after that it became to strengthen by adding heat. Heat of 700 ~ 800 C is necessary to make earthenware. This level of heat was achievable by making a large bonfire or using a furnace.
Mutation of the ASPM gene determining the number of neurons in the cerebral cortex is estimated to have occurred about 6,000 years ago. The ASPM gene was identified as a causative gene of a genetic disease that became encephalopathy with a recessive mutation. As ASPM mutation coincides with the time of character or city formation, is it a genetic cause of urbanization ability?
Eyes of European people are blue (blonde hair, white skin), which is derived from mutation of HERC gene 6,000 - 10,000 years ago. From the analysis of genes it was thought that a group with a blue eye gene migrated from the shores of Black Sea to Europe. The HERC gene controls the neighboring OCA2 gene (expressed in black pigment cells, which seems to be involved in the biosynthesis or intracellular transport of melanin). Is the blue eyes spread among Europeans due to gender selection?
Most Africans and Asians have an old type (111 A) of SLC24A5 genes involved in skin color. The new type of gene (111 T) differs by 1 amino acid, 99% of the Caucasian has it. It is estimated that this change became dominant among Caucasians 5,000 - 12,000 years ago.
Several city names (including Ur of Caldea) were found among the letters written on Sumerian clay board known as the oldest letter, but most of them were not Sumeric. On the other hand, it was written in an unknown language, not the language of other Semitic people that had hostile relations. This suggests that the Sumerians were not from this area from the beginning but people who emigrated from other places and borrowed words from unknown people who originally lived in Mesopotamia .
The ancient English who made Stonehenge is believed to have been hunting-gathering life 6000 years ago. The origin of the people who lived in Britain during the Neolithic Age are regarded as Anatolia (modern Turkey).
Since 8,000 years ago, Mesoamerica began cultivating life changed from hunting-gathering life. Maize is a typical example. Making pottery and weaving cloth started independently.
6,000 - 5,000 years ago: The hypsithermal period ended, then the interior of the continent dried. Nomadic people gathered around the large rivers. Around the area, farming and nomadic culture fused. The development of agriculture and livestock farming had made human living stable and affordable. The population had increased more than ever, the settlement developed into a large village, a city state emerged.
Mesopotamia was located downstream of the Tigris / Euphrates river, which was a very suitable area for agriculture at that time. The oldest ruins are of the Sumerians. Flood control and irrigation were done in 6,200 years ago. Agriculture was the main industry. Although the village was scattered, several city states were established 5,500 years ago. Letters called sphenogram began to be used. Sumerian city states fought each other over a farmland. One of them is the land of Eden. The nomadic people of this time had great military power, sometimes they seemed to eradicate the agricultural tribe and the forest people.
5,500 years ago, in the Sumerian city-state, clay pieces called tokens, engraved with the prototype of letters, were used as a record of trade. This is the prototype of both money and sphenogram.
The oldest library in the world in ancient Babylonia was built about 5,000 years ago and contained a large number of clay tablets engraved with sphenogram. In addition, the number of clay tablet documents found in the Sumerian ruins was about 300,000, 95% of which were records of the national economy. Bills, receipts, sales contracts, adoption and contractual consents, testaments, worker and salary lists, letters. The rest are votive texts of goods and buildings, accounts of temple property (mainly grain), educational documents, religious documents on spells, and literary works. Literary works are myths and epics, including lyric poems (threnody, hymns) and didactic poems (proverbs, wisdom literature).
The oldest copper product was made 6,000 years ago on the Anatolian Plateau in Turkey. Bronze was first made in Anatolia and Mesopotamia 6,000 years ago. Copper was relatively easy to obtain, but tin was not found in the both regions and was found nearby near the German-Czech border or in the Britain. It is said that the Phoenicians transported the tin. Bronze spread to Egypt, China and Indus.
Downstream of the Nile River was also a fertile land. The Nile River regularly flooded every year, and flood control project created the history of Egypt. Because Egypt was surrounded with deserts and a relatively isolated area, the development of the Kingdom occurred first in the world. The flood control project of the Nile River required enormous labor and large-scale collaboration, so a strong leadership was born. By around 6,000 years ago, 22, 20 Nomos (small tribal state, city state) were formed, respectively in the upper and the lower Egypt. Eventually they gathered up in the upper and lower Egypt. Finally, 5,000 years ago, the first dynasty was unified by the legendary King Menes, first Pharaoh of Egypt. Hieroglyphs were used in Egypt.
Varna civilization was established on the west coast of Black Sea 6,000 years ago. Gold products are featured. Horseback races with Kurgan culture spread old Indo-European family of language in Europe and the Middle East. Beakers formed their own culture on the Iberian Peninsula 5,000 years ago, emigrated to Central Europe and spread their culture. The original Beaker people was from a nomad who lived in the meadow area spreading from Ukraine to Kazakhstan.
The oldest rampart of China is the castle wall of Chengtoushan. It was a city surrounded by a 360 meters diameter circular wall built in 6,400 - 6,200 years ago and has a castle gate in north, east and south. The altar was built and rituals wishing for the rich rice farming were held there. Yangtze civilization is a civilization based on a rice farming and fishery, it was an ancient civilization heterogeneous to so-called the four great civilizations based on upland dry field and pastoral type.
5,000 - 4,000 years ago: As agriculture became popular, civilization developed dramatically. Demand for fire increased due to brick making for city construction, earthenware making, smelting metal, and growing population. In the plain, forest trees were cut down and used as firepower. At the same time, the destruction of the environment began that turns the forest into agricultural land.
There is a mystery that there is no evidence that people lived in ancient Southeast Asia from 6,000 to 4,000 years ago. About 5,000 years ago, Southeast Asia was hit by a drought that lasted for 1,000 years. Examination of the annual rings of the stalagmites in the Tham Doun Mai cave in northern Laos found evidence of a drastic decrease in precipitation 5,100-3,500 years ago. During this period, the green Sahara turned into desert, the Akkadian Empire collapsed, and the city of the Indus Civilization was abandoned. In addition, in a climate simulation where Sahara is desertified, not only the monsoon in Southeast Asia disappears, but also the El Nino phenomenon is prolonged in the Pacific Ocean, and floods occur frequently in East Asia. In China, Yu the Great, who ruled the flood, built the first dynasty, Xia.
The northern part of Mesopotamia is called the Assyrian region, and the southern part is called the Babylonian region. The Babylonian region is further divided into the Akkad region in the north and the Sumer region in the south. In the middle region of Mesopotamia, Akkadian started to live, a nomadic branch of Semite peoples. They accumulated power while learning the culture of the Sumerian people. Finally, the Akkadian conquered the area of the Sumerians in the south and founded the Akkadian dynasty 4,200 years ago. King Sargon was able to conquer the Sumerian due to their out-standing army which had a swift mobility with the bow and arrow as the main weapon. King Sargon of Akkadian unified the tribes of different languages, so he decided to use Akkadian as a common language. He also made a zoo. Since Sargon ruled humans, he might have thought to control animals next time. Naram-Sin, the fourth King of the Akkadian Empire, declared himself a god first in history. The Akkadian dynasty declined in 200 years. In the political confusion, the Sumerians recovered their forces again, the Ur 3rd dynasty was formed. King Ur-Nammu, the founder of this dynasty, is known as the publisher of the world's oldest law (Ur-Nammu Code) prior to the Hammurabi Code.
In Egypt, the pyramid was built during the Old Kingdom era (5,000 - 4,100 years ago). Especially the huge pyramid was made in Old Egyptian Kingdom 3rd-6th Dynasty era (4,600 - 4,200 years ago). The Three Great pyramids and Sphinx are very famous of the 4th Dynasty, located in the suburbs of Cairo, of the King Khufu (the largest pyramid), Khafre and Menkaure.
The Crete civilization was established in the Aegean Sea in the eastern Mediterranean. People who came across the sea from the advanced regions such as Egypt, Anatolia, Syria and Lebanon and others actively worked around Crete. About 4,600 years ago the Bronze Age began in the island. Agriculture was done such as wheat and olive, livestock farming such as sheep and goats. In addition, maritime trade has developed, and the Cretan is regarded as the oldest maritime commerce navigator in the world.
4,500 years ago, Beakers moved from Europe to the UK, and almost began to occupy the population of Britons, to 90%.
In the Indus river basin, ruins are found such as the planned cities Mohenjo-Daro and Harappa. These cities were constructed 4,500 to 3,800 years ago. Indus civilization is a bronze civilization, irrigation agriculture and livestock farming were the main means of production. Indus characters and stamps are left. They had traded with the Nations in Mesopotamian region. Hypothesis has arisen that one of Mesopotamia's Nations made the cities for trade or the colonies because it looks like as if high-level of civilization would suddenly appear.
The situation of China in this era is currently being constructed. In the Yellow River Civilization such Yangshao and Longshan culture, villages were formed depending on farming and hunting. Coloring earthenware is characterized by Yangshao culture, and black pottery baked at high temperature is in Longshan culture. As the heyday of Yangtze civilization, where rice cultivation was main industry, there are Qujialing culture and Liangzhu culture. Many tools made of gemstone were excavated, and trade with Yellow River civilization was also demonstrated. Although the age has not been confirmed, the Sanseitai ruin of Sichuan Province was established around this time and had its own culture.
There is reliable evidence that production of Chinese silk dates back to 4,570 years ago. The old silk found in the city of the Indus civilization is considered to be 4,450 to 4,000 years ago. For production of silk, oak silkmoth was used in India and silkworm was in China.
4,000 - 3,500 years ago: The kingdoms were established in various places, and built city civilizations. The letters were invented in ancient Babylonia, Egypt, China, Maya civilization. By using letters, society was recorded, organized, authorized and became the foundation of the kingdom.
In Crete, large palaces were built about 4,000 years ago in Knossos, about 3 700 years ago in Faith, and in Maria. The city developed around the palace. Labyrinth of Knossos is famous. The palace without a wall shows they were a bright and peaceful marine civilization. They already had characters. They made progress from early pictograms to line characters. People recorded the accounting of the palace on the clay board. Cyprus produced abundant copper which was traded by the Minoans. The eruption of Thira volcano destroyed the Minoan city 3,600-3,500 years ago.
The middle Kingdom era (4,100 - 3,600 years ago) was started by local big families living in Thebes at the middle of the Nile river. They extended the power to unify all Egypt and set the capital on Theve. In Egypt, they further developed technology to make copper from copper ore. As a burial item of King of Egypt, many copper needles, pins and bracelets are excavated. In 3,600 years ago, the Hyksos of Semitic semi-nomads invaded into Egypt from Syria. The Hyksos overwhelmed the Egypt army with Chariots pulled by horses, conquered the Middle Kingdom. Egyptians were to be under the control of foreigners for the first time for about 100 years.
After Sumer and Akkad, it was Semitic Amul who dominated Mesopotamia. About 3,900 years ago they built Babylonian kingdom with Babylon as the capital. King Hammurabi of the sixth unified the Mesopotamian region by the war of 30 years of conquest and built a centralized nation. Hammurabi enacted the law which is the culmination of the laws of the past. The ancient Babylonian kingdom became the center of thought and civilization in West Asia. The King Hammurabi set a calendar and developed the legal system. The King declared release of people from slavery and debt, which was regarded as a deal with God. Using copper, metalware was made. The Babylonian and its sphenogram became the diplomatic language of West Asia. Their astrology, calendar, building technology, weight unit and so on affected Greece as well. The ancient Babylonian kingdom declined after King Hammurabi's death and was destroyed by Hittites 3,530 years ago.
The prosperity of the ancient Babylonian kingdom stimulated the surrounding ethnic groups. A large number of ethnic groups advanced to Mesopotamia aiming for wealth. Also, nomads in Iran and Asia Minor, Central Asia, Northern Russia's Indo - European tribe have made a big move. Hittites first moved to the Anatolian peninsula where they learned the production technology of ironware. Hittitis conquered the surrounding tribe and beat the old Babylonian kingdom, but their kingdom was short-lived. The Aryans migrated to ancient Afghanistan from 4,000 years ago to 3,500 years ago. The Aryan people are divided into two, one migrating to Punjabi (Indus basin). The other moved to Iran and became Iran-Aryan. Some historians have a doubt about the existence of Aryan people.
4,500 years ago, the Phoenicia merchant had a record of carrying tin. Bronze (an alloy of copper and tin) was invented 4,000 years ago. Copper was too soft for weapons, but it became harder when turned into bronze. Furthermore, bronze was free to deform, weapons such as swords and spears developed. The technique of making bronze quickly spread all over the world. In the ancient China, sophisticated bronze wares were made in the age of the Shang (Yin) 4,000 years ago. Bronze and its accessories also functioned as money.
A city state Erlitou was born 4,000 years ago at the middle of the Yellow River, China. Erlitou is regarded as the legendary Hsia dynasty. A large amount of jewel instruments and bronze ware was excavated. About 3,500 years ago, the Han Chinese people arrived in northern China and oppressed the indigenous people of the Yangtze River Basin (originally thought to be people who lived on the continent of Sunda). The Han people established the Shang Dynasty. Ethnic groups of the Yangtze River basin spread to Japan, Southeast Asia, Polynesia. They are the people of the Altai language.
Many ancient civilizations appeared on the plate boundary. There are risks of earthquakes, volcanoes and tsunamis, but in general, they are rich in water. A moderate natural disaster may encourage people's cooperation and preparation, and may have revived the challenge spirit.
3,500 - 3,000 years ago: Nomadic people in Central Asia moved to various areas. This is the oldest record written that nomadic tribes entered into the ancient civilization area. Ethnic groups who lived near Egypt and Babylonia became civilized under the influence of ancient nations. Iron was made in Anatolia 3300 years ago, but at that time, it was lump iron. The iron was not completely melted, so it was reheated and beaten to make wrought iron.
The Phoenicians started to form city states 3,500 years ago. They developed shipbuilding and navigation technologies from 3,200 years ago, and conducted sea trade, and advanced from North Africa to the Iberian Peninsula. The alphabet is thought to have been invented by the Phoenicians as a convenient letter that mediates Mesopotamian Sphenogram and Egyptian hieroglyphs which are both trading partners. The prototype of the alphabet was born in the ancient Orient. The Phoenicians conveyed the excellent civilization and culture of Mesopotamia and Egypt throughout the Mediterranean, and promoted the development of ancient Greece and ancient Rome.
From 3,500 years ago for several hundred years, Dorians and Achaeans, move down to south of the Balkan Peninsula. They destroyed Mycenae and Creta civilization 3,200 years ago, and swept the eastern Mediterranean as sea people. They built many cities called Polis like Phoenicians. Later, they are called Greeks.
Egypt ran out Hyksos. Egypt came to the most prosperous era in 3,500 years ago, including strengthening militarism and conducting expeditions abroad. King Tutankhamun of Egypt 3,300 years ago is famous for its golden mask and coffin. Egypt battled with the mighty Hittite Kingdom at Kadesh, but later had a co-prosperity posture such as got marriage. Egypt declined gradually from 3,000 years ago and received invasion by Assyria and Persia.
The ancestors of Hebrews are people who emigrated to the present Israel from Mesopotamia around 4,000 years ago. Some groups moved to Egypt (due to famine? Hittite's mercenary? Egypt invasion?). They were treated as a slave under the New Kingdom of Egypt. About 3,200 years ago, a group led by Moses escaped from Egypt. They established Judaism and became the backbone of the later Jewish people. They built a kingdom and prospered in era of King Solomon.
Mesopotamia invaded the nomadic tribe from Central Asia, and many kingdoms such as Hittite, Mitanni, Cassito were established in parallel and were in a state of antagonism. Meanwhile, practical academic technologies advanced such as arithmetic, 60-digit method, astrology, formation of calendar, law, etc.
The Indus civilization flourished in the plains that crossed the Indus River Basin to the present Bombay, but it was destroyed about 3,800 years ago. Later, Aryan people gradually moved to the same area by clan from 3,500 years ago. As the Aryans had technology of iron usage, they could dominate the Dravidans who had a dark skin color. Creating a caste system (class system) based on their religious thought, they were in the ruling classes Brahmin and Kushatria.
In China the King Tang opened the Shang dynasty 3,500 years ago. In a history book Shiki, it is called Yin. Characteristic of politics of the Shang is theocracy, decided by divination all the national affairs such as politics, military affairs, agriculture, etc. by using the oracle bone script. The oracle bone character is a prototype of Kanji. Production activities were carried out by clan, and ancestral worship was regarded as the root of their religion. Many large bronze bowls with bizarre designs were discovered, showing that they had advanced technology to make bronze ware. The Zhou dynasty that occurred in the western part of China gained a know-how to make iron through trades with the central Asia region. 3,000 years ago, King Wu of the Zhou dynasty beat the King Chou of Shang dynasty.
In Central America, the Olmecca civilization was established about 3,200 years ago, and reached its peak in 2,500 years ago. In addition, the Sapoteca civilization was established for 2,600 years ago. They devised a Maya character, and built many monuments. They also created a long-term calendar that starts in 3,114 BC. The Maya character is a pictogram that contains pictures and symbols characterized by the profile of a human or animal in a square.
2,500 - 3,000 years ago (BC 1,000 - 500 years): The national backup is necessary for practical use of iron. Iron technology was also necessary for military power to maintain and expand the nation. Roman was founded. Hebrew was at its peak. Brahmanism and caste were established in India. In China, Zhou dynasty collapsed due to the invasion of nomadic people, and entered the spring and autumn period. Iron was spread in Europe.
It is thought that modern nomadism was established about 2,800 years ago. They were control of flocks such as castration and equestrian, technology of milking and processing. Nomads have a lot of dependence on agricultural production. Nomad industry was trade and livestock supply. They governed grassland areas where agriculture is impossible.
The Celts in Eastern Europe (Romans called Gaul) had resided in the upper line of the Rhine, Elbe and Danube rivers. They had the power gradually to drive away the aboriginal people, and spread to almost all Europe before 2,700 years ago. The Celts were the first European representatives of ironware culture. Basque people who live in the Pyrenees will be one of the aboriginal groups that was depressed by the Celts.
It was the Scythia that made the kingdom for the first time in equestrian ethnic groups. It was confronted with the two countries of Greece and Orient, based on the northern Black Sea coast, around 2,600 years ago. They were accustomed to riding horses and were the strongest troops that could use bows and arrows while riding. The army with high mobility overwhelmed Chariot, the main force of the military of other big kingdoms. The equestrian people invaded the civilization area many times in the future history and became the driving force which made Empire. The ethnic group of the Varna civilization that flourished on the east coast of the Black Sea was later called Thrace, and reached its peak as a kingdom 2,600 years ago.
Each Greek police has developed from 3,000 years ago. Although economy of Athens was based on slavery, Athens invented the Republic. Democratic politics created Ionian natural philosophy (Thales: the origin of all things is water, Heraclitus: all things flow, Pythagoras: all things are numbers, Democritus: all things are made of atoms), and in Athens, Sophists (Socrates etc) were active. 2,800 years ago, the use of casted money began at Lydia. Since Greece is a land with low productivity, they developed commercial, trade and craftsmanship and built up the monetary economic zone. 2,700 years ago, Rome was founded. Rome shifted to the Republic by influence of Athens 2,500 years ago.
In Egypt and Mesopotamia of rich river basins, neighboring ethnic groups repeatedly invaded and built the kingdom. Assyria dominated Egypt, Syria, Mesopotamia, and eventually unified Orient 2,700 years ago. Assyria has powerful armies, mainly of cavalry. They built and maintained the highway. Assyria forcibly moved many ethnic groups that defeated militarily, and imposed heavy taxes to them. The Jewish people were one of them, and in the Old Testament, Assyria is portrayed as an ethnic who favorite blood. After about 140 years of control, Assyria declined due to the independence struggle around of each country.
In India 3,000 years ago, Aryans who acquired steelmaking technology advanced to the east area along the Ganges River. Agricultural production increased, commercial and industrial yield were developed, accordingly villages developed into cities or urban states. Mixed with indigenous people (such as Dravida), progress of differentiation of the status class, the caste system was born. Brahmanism, which is the basis of the thought of the caste system, used Veda as a scripture, and the ceremony of the religion was prepared. As society evolved, the power of Kushatria and Vaisha strengthened, who had political and military power or economic power, respectively. Some of Kushatria and Vaisia, who were suffering from the domineering of Brahmin, sought new ideas to adapt to the new era. Religious people who train in the forest and conduct training and inner thinking have emerged, and the oldest philosophy called Upanishad was born. Jainism and Buddhism were established based on Upanishad philosophy.
In the Zhou dynasty established 3,000 years ago, territory was given to the family by the king (the head family), and politics was managed by the clan feudal system. When the power of the Zhou royal family declined, it became the spring and autumn period when many kings competed against each other. In the spring and autumn period, iron making technology became popular, and productivity also increased. The kings had scaled up policy of increasing wealth and military power in each country and sought talented person. In the trend of realism, many thinkers and schools appeared, and many books were written. These are collectively called "Hundred schools of thought". It gradually changed to the Ages of the warring state 2,500 years ago.
Individuals who revolutionized the interpretation of humanity appeared at the same time around 500 BC in the world. Jaspers called this the Axial Age. Great philosophers and religions were produced in the east and west, such as the Greek Sophist, Zarathustra in Zoroaster, Buddha, and Hundred Schools of China. They thought that slavery and human sacrifice should be denied, which were regarded as evils of ancient society, and that family values and laws should be respected. However, according to the historical database Seshat, the birth of new philosophies is scattered over a wide range of times from 1200 BC and cannot be simultaneous.
2,500 - 2,000 years ago (BC 500 - 0): The Earth warmed since BC500 years ago, the productivity of agriculture rose. Empires such as the Roman Empire and Han Empire have stabilized and thrived. From the introduction of steelmaking technology, society became stratified in 1,000 years, and people were separated to aristocrats and slaves. A philosophy was born from the affluent life of aristocrats.
After the Assyrian Empire is destroyed, the Neo-Babylonian Empire was one of the countries where independence had recovered. The reigns of the two Nebuchadnezzar are famous. Since the Neo-Babylonian Empire captured the Jews as slavery, the capital Babylon has a poor reputation as a evil religion or a depraved city in the Old Testament. Two kings built magnificent Jigrads and aerial gardens. The Jigrad is regarded as a model of the Tower of Babel. Achaemenid dynasty of Persia was the next empire that has expanded its power. 2,500 years ago, when Darius I established the empire ranging from northern Greece to Turkey, Egypt, Middle East, Mesopotamia, Iran. Departing from one of races of the Media kingdoms, it is their feat in just 50 years. Although Assyria did tyranny politics, Darius I was tolerant of religion and culture of the ethnic groups within the Empire. He improved the way of the king and made Aramaic a common language. He divided the whole country into 20 regions and ruled with Satrap officer. The Jews captured in Babylon was also released. The Jews who came back to Jerusalem compiled the Old Testament. This book is their foundation.
Poleis in Greece formed a Delos alliance under a hegemony of Athens and fought against Persia. Persia was destroyed the large fleet in the battle of Salamis and was forced to withdraw. Persia quitted the advance to Greece. Greek poleis, mainly Athens, had prospered. In Athens that established the Republic, Greek philosophy represented by Socrates, Plato and Aristotle was established. On the other hand, it conflicted with Sparta which was a totalitarian regime. The confrontation between them developed into a Peloponnesus war and led to the decline of the Greek society.
Filippos II stood in Macedonia, which was occupied by the Persian empire. He made a powerful army with the tactics composed with heavy infantry and cavalry, then in BC 336, conquered Greece under internal conflict. Although Philipps II was assassinated, his successor Alexander destroyed the Achaemenid dynasty Persia which was the center of the world at that time. He made an expedition to the Indus River. Alexander got the territory of the former Achaemenid dynasty Persia, but he had gone in young age. The vassal lords of Alexander gained independence in each region, and the Hellenistic countries were formed. Hellenistic culture blossomed around Alexandria city in Ptolemy dynasty in Egypt.
On the other hand, Rome, which was only one city on the Italian Peninsula, established a political organization with the law and the Roman Senate. It unified the Italian peninsula. In BC 146, Rome destroyed Carthage, the other crucified player of the Mediterranean. Rome unified the Mediterranean coast in around 100 years, with Hellenistic countries as the territory. The enormous Roman Empire put an Emperor, organized the bureaucratic organization, organized specialized armies. Rome made political control thoroughly outside of Italian peninsula as the provinces.
In India 2,500 years ago, small nations rallied, Kosara and Magata countries were the biggest two. The invasion of Alexander to India has created a unified momentum and has brought the appearance of a unified nation in India. Chandragapta lifted himself from the castle's low class and became a warrior of the Nanda dynasty. At the confusion of Northwest India by Alexander's army, he destroyed the Nanda dynasty, established the Maurya dynasty. Chandragapta expanded its power from the Ganges River basin to the south of Afghanistan and the Indian peninsula, and built the first unified state in India. The 3rd King Ashoka was the manifestation of the heyday of the Maurya dynasty. He became an enthusiastic Buddhist follower and encouraged and protected Buddhism. The Maurya dynasty declined rapidly after the death of Ashoka. Since then, many states of small powers repeatedly rushed in India.
In China, economic development is remarkable due to popularization of iron tools, each country competed against each other by accumulating power. In BC 403, after the Zhou dynasty went out, seven influential Lords in the Zhanguo period fought each other. The kanji that had been monopolized by Zhou spread out throughout the country due to the collapse of Zhou dynasty. Qin dynasty became powerful, which was located in the remote frontier of the west. In BC 221,the Qin dynasty destroyed other countries in China. The King of the unified dynasty is Sei. He became the king at the age of 13, and began to manage at the age of 21, and achieved unity at the age of 38. He called himself "Emperor" (the First Emperor).
The First Emperor made a centralized system to dispatch local governments to govern and stopped domination by clan relationship. He did revolutionary big projects such as unification of weight balance, money, and letters which were different for each country. But the rebellion increased against his brute forced method, the nation was disturbed after his death. Liu Bang (Gaozu of Han dynasty) re-established kingdom and succeeded the measures of the First Emperor. In Han dynasty, the Emperor Jing and Wu stood after the internal bloody battle, and they established Han's heyday.
In the northern part of China, there was Xiongnu with a strong cavalry army. The First Emperor built a Great Wall against them. Gaozu of Han were almost killed at the expedition to Xiongnu. In the case of the Han dynasty, Jing and Wu Emperor attacked Xiongnu and weakened their power. Han took in to the division of Xiongnu latter and drove it to the west. Military actions against Han's fellowships have brought information of the countries of Central Asia of that time and are recorded. Wang family got the power in Han, which a mother of the Yuan Emperor belonged, who pushed Xiongnu away. In AD 8 years, Wang became the emperor, by going away the Han's Emperor
AD 0 - 500 years: Compilation projects of holy books were held. The environment was cooled at around AD 300 for more than 500 years. Races with horseback people moved to the West globally, especially in Europe, it was the great movement of Germanic people.
The Roman Empire celebrated its heyday. The largest version is; England, Rhine, Borga River in the north, Mediterranean coast north of the Sahara desert in the south, Iraq in the east with battles with Parthia and Sasanian Persia. However, dispatching troops for the conservation of the territory and power battle went the Rome havoc, the senate system collapsed. Rome shifted to the centralized politics to the Emperor. After the transition to the tyranny, the Emperor Diocletian began divisional rule. Emperor Theodosius used Christianity as a national religion in order to utilize the organization network of Christianity in 380 years. In 395 the Roman Empire split into the east and west.
Xiongnu lost in war against the Han Empire and escaped to the west. Xiongnu appeared in Europe as Hun tribe. They conquered the East Goths who lived in the North Shore of Black Sea across the Don River in 375 and oppressed the West Goths. At that time, Germanic tribe of an undeveloped tribe lived in the European frontier of the Roman Empire. The government of Germanic people was based on blood relationship, with looted-type agriculture and hunting as industries. Pressured by the Huns, the Germanic tribes entered the confused Roman Empire. In 476 the Western Roman Empire was destroyed by army led by Okeador. The Western Roman Empire with a low degree of culture was divided by the Germanic tribe into the Kingdom of the Western Goat, Kingdom of Vandals, Kingdom of Burgund, Anglo-Saxon 7 Kingdoms, Frank Kingdom, East Gotha Kingdom. It is the prototype of the current Europe.
Large religious books were compiled between AD 0-500. In AD 77, Avesta of Zoroastrianism which became the state religion of Sasan Dynasty of Persia. The Buddhist scripture was translated in the book from the previous oral messages at the King of Kanishka (around AD 130 - 170). It is said that the New Testament was formed around AD 150. Buddhism spread to northwestern India during the Kushana era in the first to third century. Buddhism came there up with the faith of Zoroastrianism, Brahmanism, Jainism, Greek/Roman gods. Mahayana Buddhism was created by Nagarjuna, from religion originally only for priests to general people. In India, Buddhism was absorbed in Hinduism (philosophically approaching). Vairocana and Brahman are identical.
In India, after the confusion period in which the Maurya Dynasty collapsed, the Kushana Dynasty which was an invader from Iran was established. Buddhism prospered with the protection of King Kanishka and created Gandhara art. The Kushana Dynasty declined in the fight with Sasan Dynasty of Persia, and in exchange the Gupta Dynasty (around AD 320 - 550) was established. Under Gupta Dynasty Buddhism faded.
The East Asian society had double-layered structure of the Chinese hegemony order and the similar order of neighboring countries. In China, Emperor Kuang-wu killed the Emperor Wang and the Han Dynasty revived (AD 25). The territory became the largest at the time of the next Emperor Ming and diplomacy was actively carried out. After that the emperor continued ninth generations by relatives and eunuchs. Han did not recover. The powerful people of various places fought with the Yellow Turban Rebellion (AD 184), it became the Three Kingdoms era. Liu Bei, Kanu, Zhang Fei are famous for their Three Kingdoms. Wu (Sunkuan) and Shu (Liu Bei) united against the biggest power Wei (Cao Cao) and fought against each other, Liu Bei died (AD 223) due to split of fellowship. Zhuge Liang (AD 181 - 234) who succeeded Shu's real power dispatched against Wei, but Sima Yi prevented them. Mr. Sima held power, destroyed Shu, Wu and established West Jin. During the Chinese chaos, the surrounding ethnic groups (Five Barbarians: Xiongnu, Jie, Xianbei, Di, Qiang) entered North China. Starting from Former Zhao by Xiongnu, 13 countries rose during around 100 years. At the end of era, the northern Wei (AD 386 - 534) of Xianbei was prosperous. In South China, the three nations of the Han Chinese were established in turn. The reason why the unified dynasty was not established is that the power of local rulers was strong.
Teotihuacan civilization (BC 250 - AD 400) and Maya civilization (AD 250 - 900) were established in Central America. Teotihuacan ruins are including the pyramid of the moon, the street of the dead that extended to the east and west from the pyramid, the pyramid of the Sun along the street, Quetzalcoatl temple at the end of the street. It was estimated to have a population of 100,000 and dominated central Mexico. Teotihuacan may have been a group rule like the Roman Empire, not a royal government. Maya civilization is famous for Acropolis temples in the center of Copan ruins and Tikal ruin. A long-term calendar and a Mayan letter inscription engraved on a stone remained, and many city-states flourished around the central and southern lowlands. The royal system that adopted the advanced culture of Teotihuacan was their basis of politics. Unlike the so-called four major civilizations of the other continents, the civilizations of the Americas did not use the large river. Many cities flourished in the tropical rainforest. It was a city civilization in Neolithic age without metal instruments such as bronze ware nor ironware. They did not have domestic animals such as cattle and horses. The wheel was not put to practical use. Because of that, the dynasty which unified the whole region was not born.
AD 500 - 1000: Global warming occurred mainly in around AD 900. The activities of the northern ethnic groups had increased. The area that nations were established expanded toward the North.
In the UK, after the Roman Empire withdrew, seven countries of German, consisting of Anglo-Saxons, were fighting against the Celtic country. Essex unified England in 829. After that, UK got the entry of Viking. Several German countries and the Byzantine Empire (East Roman Empire) were fighting in the central part of Western Europe. The Kingdom of Frank has expanded his powers. The King Carl (reign 768 - 814) expanded the domain to France, North Italy and the western part of Germany at the time. The Byzantine Empire also strengthened its power from the Balkans to Southern Italy. The Kingdom of Frank and the Byzantine Empire became the military background of the conflict with the Roman Church and the Constantinople Church, which became Orthodox faith. The Kingdom of Frank was divided into three countries by the grandchild of Carl the Great in 834, into the West Frank Kingdom (France), the East Frank Kingdom (Germany).
In 610, Islam was established with Muhammad as a founder on the Arabian Peninsula. Muslims built a caliph country and destroyed the Sasan dynasty Persia who had fought with the Byzantine empire. After Muhammad, the caliphate was elected and lasted until his fourth generation. In 650 the only Quran was compiled. Moawiyah assassinated the fourth caliph, Ally, and established the Umaiya dynasty. Muslims have divided into Shia Islam who do not recognize anything other than Ally as a valid caliph and Sunnah Islam who accept other caliphs. Islam may be the result rather than the cause of the Arab conquest. Both Christianity and Judaism claim similar historical grounds. The religion insist that there was an inevitable reason for its birth, and that became history.
The Umaiya Caliphate robbed the territory in North Africa of the Byzantine Empire, expanded its territory to Iberia Peninsula, Morocco at the west and to Iran at the east. Later on, the Abbasid Caliphate pushed the Umaiya Caliphate away. The Umaiya Caliphate moved its capital to the Iberian Peninsula. In the Abbasid Caliphate they introduced paper technology through the war with Tang. They translated Hellenistic culture and Chinese classics and constructed a huge library. Shia Islam founded the Fatimid Caliphate mainly in Egypt. The economy developed in the Islamic cultural area, a culture blossomed that blended Greek, Hellenism, and the heritage of India.
In the height of the Abbasid Caliphate, Islamic merchants used Dow ship to create a worldwide trade network. The center of the network was Bakudat. When they went to the west, they entered the Mediterranean from Damazukus, went through Tunis, Cordova, throughout the Atlantic, to Tombuktu in West Africa. When going south, to Mecca from Persian Gulf, Aden, reached to Malindi and Kilwa in East Africa. When going north, from Samarkand to Chang'an via Kucha (Silk Road), or from Constantinople to Kiev. When going east, cross the Indian Ocean from Calicut to Malacca, to Guangzhou and Yangzhou of China. It is the world of Arabian Nights story.
In India the Hindu kingdoms had battled each other repeatedly. In Southeast Asia, the conquest dynasty developed due to the influence of civilization in the Indian sphere. The influence of India was presumed from the transmission of letters. Cambodia's Angkor Wat (around 800) is famous as the ruins of this time.
In China in 588, Yang Ku established the Sui dynasty and put an end to the era of Sixteen Kingdoms. Sui dynasty was short lived because the Emperor forced large scale civil engineering works and wars. Then Tang dynasty (618 - 907) was founded. Tang dynasty developed into the global empire, its territory was to the west to Turkestan. It was because the foundation necessary for maintenance and operation of the empire was established in the era of the Sixteen Kingdoms. First, the ranking system of the executive branch (nine class system: incorporation into the regime of local strong ruler) was established, then it moved to a clan (a government official appointment system by examination). The Chinese examination system was a selection system that guarantees fairness and objectivity. It also established the land ownership mechanism and collect taxes (Equal-field system). The bureaucracy was set as the three ministries plus six divisions which was the system of three powers under the emperor. Paper technology made a big contribution as a medium for recording and transmitting information to support the bureaucracy. Tang dynasty was destroyed in 907. After that, the Dynasty diverged in the north and the south, the two major cultural spheres named the fifth generation ten countries were established.
In the Eurasian grassland region, new nomadic forces from Eastern Siberia, such as Mongolia and Manchuria, appeared one after the other, and they moved to the agricultural area in the south and the grassland in the west. In Central Asia, the Turkic people first expanded their forces and founded Gokturks dynasty. They built a great empire ranging from the west the Aram Sea to the east to Manchuria, and conflicted with the Islamic empire or Tang dynasty. Gokturks was annihilated by Uighur of the same race (744 - 839). Then, the Kyrgyz ethnic group is founded. In Manchuria, after the Tang faded, Liao (916 - 1125) was founded. The founding movement came active in Japan and Korea, and the conquest dynasty was formed respectively.
Maya civilization celebrated in Central America. Many cities representing Teotihuacan have been built. But suddenly the city was abandoned from the 820 to the 889 (the last date of the monument). The cause may have been written in the book incinerated at invading of Spain and Portuguese. Analysis of the annual stripes deposited on the Cariaco Basin on the coast of Venezuela revealed that discontinuous but severe drought occurred several times at the time of the destruction of Maya civilization. There were 6 droughts in 9 years from 810, then 3 years from 850 and lastly, three droughts during 6 years from 910, hit the Maya civilization. No matter how flourish a civilization goes, but when food shortages continue for three years, it would collapse. After Maya civilization, the Torteka people advanced.
List of African empires.
The characteristic of the African empire is that it disappears from the map without invasion and occupation by another country.
1,000 - 1,500 year: The birth of a global society
The Iranian Buyid dynasty invaded the capital city of Abbasid dynasty, and in 945, the caliph of the Abbasid became a mere facade. In 1055, a Turkish Nomadic, Seljuq Turkey, in the Central Asia released Bakudat from Buyid dynasty. Abbasid caliphate appointed the King Tughril Beg of Seljuq Turkey as Sultan and allowed to administer as an authoritarian state. Seljuq Turkey entered Anatolia and oppressed the Byzantine Empire.
In Europe, living Germanic ethnic groups were under aggression of Viking from the North, Islam from the South, Majar people from the East. European countries began to function as a national group centered on the Western Roman Church. The Pope of Byzantine Empire asked Western Rome church for assistance against Muslim invasion. European countries pretended to help the Pope, and formed the Crusade to invade the Middle East region for a new territory (1096 - 1270). Initially the Seljuq dynasty was in a state of division so the Crusader occupied the eastern coast of the Mediterranean. Jerusalem was plundered, the inhabitants were massacred, the kingdom of Israel was founded. Saladin who set up the Ayyub dynasty (Kurdish) organized army and kicked out the Crusaders (1187). Although the crusader's invasion continued thereafter, the Ayyub dynasty that the capital city was Cairo and then Mamluk sultanate repelled them all.
The period from 800 to 1300 was a mild temperate period of global warming. Viking was active in Europe, from England to France, to the Mediterranean. The Kingdom of Sicily is a Norman country. They went to the west for Iceland and Greenland. Viking, who explored North America, was Reef Ericsson, and his mythology remains. It was about 500 years ago of Columbus trip. Viking headed to the east established the Kingdom of Novgorod, and Kievan Rus'.
The Turkish ethnic group worked as a foreign soldier in the Abbasid dynasty. They determined Muslim as the state religion, established the Karahan country in the Central Asia. They also reached the Ganges river basin of India and established the Ghazna dynasty, the Goal dynasty in the 13th century (Delhi sultanate dynasty, 1206 - 1290). Since then, conflict between Muslim and Hinduism began in India.
The Slave dynasty was held in India in the 13th century by Aibak. Since then, until the Mughal Empire of the 19th century, the Muslim dynasty dominated in India. Muslims were open to other religions, so Indian domestic religions never went out.
In China, Zhao Zhengu established the Song dynasty (Northern Song) after era of the fifth generation ten countries. His brother Zhao Ming was reunified China in 979. Song dynasty was pressed by the northern ethnic Liao and Jin dynasty, but Song had governance by law and reason rather than by military force. Its culture had prospered greatly. Especially since the South Song (1127 - 1279), the development advanced in Gangnam, agricultural production improved dramatically. Special products such as tea, ceramics, silk were born. Merchants dealing products had political power, and economic systems also developed. Compass, gunpowder, and printing technique were invented. Cheng Zhu school which summarizes the Chinese thought and respects a rational mind was born. Weapons using explosives invented in China were developed in the war between Song and Jin, and evolved as weapons to throw fire. Mongolia used these firearms and improved explosive bullets. Mongolia transferred them to the China.
It was Mongolia that oppressed Muslim countries after the Crusade. The Mongol army led by Genghis Khan destroyed the West Liao dynasty, obtained key cities of trade in Central Asia, destroyed the Kingdom of Islamic Horasm which dominated Central Asia and Iran (1231). The Mamluk sultanate won Mongolia and prevented the invasion of Mongolia to North Africa. After conquering Eastern Europe, Russia and the Middle East, Mongolia began to invade into China of great powers.
Mongolia beat Jin dynasty (1234), destroyed the South Song (1279). Invading Korea and Vietnam, it also attacked Japan. At this point Eastern Europe to China was to be tied up in the Mongolian Empire's transportation and economic system. Islamic culture, science and technology of West Asia was transferred to Han Dynasty. When the expedition of Mongolia ended, Arabian, Iranian and Turkish Muslims moved to China one after another. They were called Semu, estimated to over 1 million people. Mongolia retreated to Central Asia when Red Turban Rebellion occurred in China. After that, the Timur Empire took over Central Asia and in the Middle East Ottoman Turkey expanded its influence. Ottoman Turkey, founded in 1299, was one of the local governments, but organized a powerful army and advanced from Anatolia to the Balkans. Once destroyed by the Timur Empire, it was revived and restored its territory. Mehmet II in 1453 fell Constantinople and destroy the Byzantine Empire.
In Europe, the merchants in each city on the Mediterranean coast accumulated property since the crusade activity. Greek and Arabic literature was translated into Latin in the 12th century. The Islamic scholarship, which was at the highest level in the world at that time, was transplanted to Europe and Renaissance of the 12th century started. The modernization of Europe can be thought of as the result of people moved to the South due to transition of climate from warm to cold. The kingdom was centralized while the powers of the Pope and the small owner were weakened. Europe was not invaded at last by Mongolia having its domestic problem, and also by the Timur empire. However, the Nomadic tribe is a major threat to Europe and prepared a military regime to prepare for their invasion.
In North Vietnam, Lee Dynasty was founded. The Pagan dynasty established in Myanmar imported the hinayana Buddhism from Sri Lanka and made it the state religion. Buddhism was transmitted to Thailand, Cambodia and Laos.
In Central America, the Tortekas came to hegemony until the year 1200 after the Maya civilization. After that, the Aztec empire invaded and the Central America was under Aztec until the Spaniard destroyed the Aztec empire. The Cusco Kingdom was established in the 13th century on the Pacific side of the Andes Mountains in South America. It was united as the Inca Empire by the King Pachacuti in 1438. In the heyday, there were 80 ethnic groups and a population of 16 million in Inca Empire.
The plague struck the countries united by Mongolia. The plague, which was endemic to the steps of Central Asia, reached China in 1345. It struck Constantinople in 1347, was brought to Genoa and Venice by ship, and spread to Europe the following year. It has killed one-third of the population of Europe and China. This plague shook the feudal system and brought about a more fluid society.
1500-1900 years (Asia: from 40 degrees east longitude to 160 degrees west longitude): The empire system with hereditary leaders has Limited prosperity.
Ming (1368 - 1644) was established in China who kicked out the Mongolian people. Advanced bureaucracy based on the rule of law was set up, and a tyranny was born. After governance by Emperor Yongle, its heyday period, domestic politics were appropriated by mediocre emperors. Disturbance by neighboring ethnic groups often occurred. However, the national consciousness of the Han people greatly increased.
Manchuria constructed political power over three generations from around 1600, dominated China by the corruption of Ming regime, and established Qing (1636 - 1911). The era 140 years of Kangxiang, Yongzheng and Qianlong Emperor were at their peak. The Manchu people became Chinese civilization about politics, economics, and culture, but forced to the Han people through clothes and hair styles. Resistance of the Han Chinese continues long, and Qing has expanded the territory every time it drove the resistance away. Many Han people became displaced people, and formed an overseas Chinese society mainly in Southeast Asia.
Russia was under Mongolian rule, but in 1480 the Grand Duchy of Moscow became independent under Ivan III. Russia culture was a Central Asian style. They converted farmers into villeins and built a tyranny. At the time of the next Ivan IV, he expanded his territory, hired a Cossack soldier and advanced to Siberia. After this, confusion continued for a while, Romanov dynasty was established, especially Peter I (1682 - 1725 years) changed culture to European style. Russia entered the Baltic Sea, had a war with Sweden to build a port town of Petersburg, and signed a treaty with Qing, thus obtaining control of Siberia.
Migration and diffusion of Islam made progress towards Asia from the 13th to 18th centuries. First, India. From the Goal dynasty to the Delhi Sultan dynasty developed, finally established the Mughal Empire. And to Southeast Asia. Most of them are mediated by commercial trade.
In the 15th century, a huge and complicated trade community network appeared with autonomy from the coast of China to the Indian Ocean. Even if the state power was trying to control them by force, they fled to the sea, shifting their base of activity to a distant port far from the state power. This network is composed of mainly Muslim, local people, China, and Hindus. Japanese pirate, which has mainly exercised power in the East China Sea from the 14th century to the 16th century, is one of them.
In East Asia, there was a principle that the rulers guarantee security and equal trade opportunities in the trade zone and leave the problem handling to merchants and residents to their autonomy. From the 16th century Europeans came to appear in East Asia from South Asia and Southeast Asia. The Portuguese brought in maritime control. Fearing the Hideyoshi's approach to the south, Spain will send a battleship to Taiwan in 1598. It was 1597 years that Ming took the troops stationed in Penghu Islands in preparation for Hideyoshi's southward movement. Europeans succeeded in industrial revolution in the 18th century, developed low-price textile products, gradually dominated the commercial network. After that, with the backdrop of armed force, European politically intervened in the unstable period of Asian countries, expanded their colonies.
A ban of pirate policy was implemented to crack down on Japanese pirate activity. This is the origin of closure of Japan. In Japan, the closure policy is for the Shogunate to monopolize relations with foreign countries, and it excludes Christianity related powers which can be said to be the essence of Western culture. The selective acceptance was strengthening of foreign culture by the Shogunate. Closure policy was never a system to block all external relations and reject foreign culture.
Descendants of royalty of the Timur empire invaded northern India from Afghanistan and built the Mughal Empire (1526 - 1858). Although the royal family was Muslim, it adopted a consolidation measure against the Hindus and expanded the territory to the south. Aurang Zebue (ranking 1658 - 1707) conducted Islamic-centered politics, inviting resistance of Hindu and other religions. British intervened in that turmoil, the Mughal Empire became a colony of UK.
Ottoman Turkey fell Constantinople in 1453. They determined the city as their capital and renamed as Istanbul. It expanded the territory to Egypt, Iran, seized governance of the Mediterranean Seaside and approached Eastern Europe. The Ottoman Empire kept pressing on Europe for a long time, maintaining a powerful force. In 1922, the Sultan system was abolished with the democratization revolution of Turkey.
In a major cultural area with a long history, a new state was born even if confusion occurred, the central government was immediately recovered. In stable society, merchants are guaranteed property, so credit transactions were smooth and active. The developed transport system, a unified money system allows merchants to operate in a wide area. Besides currency that was functioning only in daily transactions within the region, the currency necessary for settlement was set between long distant regions. Gold or silver was used as the material for such a currency and gained consensus as an international currency in a wide area. Accumulation of wealth was promoted after expensive currencies circulated. As the bureaucracy matures, it restricts free trade and international exchange to maintain domestic order.
1500-1900 (other than Asia: from 160 degree west longitude to 40 degree east longitude) European countries got super power and started to reform social structure on a global scale.
In the historical view of Europe, the era of the great voyage began at the end of the 15th century. However, it was small scale. European adventure team crossed the Pacific Ocean about 1,000 years after indigenous people of Micronesia and Polynesia made a voyage. Since Ottoman Turkey was a great diplomatic enemy, Vasco da Gama bothered to discover a route to India through Africa going to the Independence Peak. The Santa Maria was a so small ship that Columbus got on and found the American continent, which was only about a sixth (one sail) of the ship that Zheng Hu had sailed to the east coast of Africa 100 years before Vasco da Gama. Zheng Hu led a fleet of 1,000 vessels.
Ottoman Turkey was the biggest military threat to Europe, on the other hand, played an important role to grow Europe countries socially and culturally. In addition to the support of the Renaissance by cultural exchanges, Ottoman Turkey interfered with the internal conflict and religious reform in Europe.
The year 1492 is a memorable year for Spain. Spain displaced the Islamic forces from the Iberian Peninsula (Reconquista). Also, Columbus arrived at the America continent which opened the way to enter the America continents. In 1533, the Inca Empire was destroyed. The kingdoms of the America continent without cavalry and iron-making technology succumbed to the pressure of Spain. The Inca Empire was looted by a large amount of gold and silver, the people enslaved by mining development and farm management by Europeans. It resulted the population of the continent decreased to one tenth. Spain plundered a large amount of gold and silver, but practically it only improved the trade deficit against Asia and Islam.
Around 1540, the firework gun developed in Spain transformed the ways of the wars. On behalf of a well-trained cavalry party, civilians with guns became the main power of solders. The horse-riding nomads ruling actively in Central Asia were completely sealed up. Europe has advanced to the world centering on trade, with a background of military force. East India Company was established around 1600. European countries have come to interpret the world with Christian standards. Therefore, Europeans clearly distinguished, discriminated, and disrespected to the world deviating from their standard. It is a basis for physically consolidating the residential area of other people as its own area. European countries have expanded their dominant regions in Asia and forced the natives of their values.
Europe has supplied labor from the African continent for the development of the America continents. Triangle trade, exporting goods from Europe, buying slaves in Africa, exporting slaves to the America, buying sugarcane and cotton etc, and processing it into industrial products in Europe, is particularly profitable. Europe increased its economic power and technology to the world level. On the other hand, Africa's population was said to reduce by one third.
Europe was a backward region, and was struck by the invasion from the East regions and the wave of the global monetary economic system. Now Europe became equal to Asia in the 1700s. Europe has developed its own culture since the Renaissance. They invented three fundamental concepts, human rights, capitalism, and scientific methodology.
Europe created a system other than the monarchy for governance of the state. Until then it was common sense that the conqueror would become the king. The foundation of new government was born in the UK, the United States without the king was born (1776). In France, the revolutionary army executed their king (1793). The state administration by Congress was democratic. The concept of public was born, fundamental human rights were invented. On the other hand, the war became a work of the people, the war itself became a harsh political act. With the emergence of a national war, European countries colonized the world against the background of a strong army. In 1840 Opium War. In 1877 the UK colonized India. Only colored race who kept complete independence at the beginning of the 20th century was Japanese.
In the United States and Europe, black people became absolute lower-class citizens who were abandoned African culture (by being destroyed) and brought to the America continents and Europe as slaves. Yellow races were able to act as a citizen who can compete equally with Caucasian because their home culture is preserved. At the time when the Chinese began immigration, they were under pressure and discriminated. After slavery was abolished, Asian immigrants to the US increased rapidly.
The Japanese archipelago stretches over 4,000 km from north to south, and there is archaeological and anthropological evidence that humans have lived there for more than 30,000 years. Currently, three ethnic groups, Ainu, mainland, and Ryukyu, are distributed in order from the north. It was the descendants of an old type of Asian population who lived in Southeast Asia that first emigrated to the Japanese archipelago about 15,000 years ago to form the Jomon people.
The distribution of various precious stones in the Jomon period was about 200 km from the production area. For example, obsidian, which is hard and smooth and is the best stone tool material, is not so common. This production area is Shirataki in Hokkaido, and Kozushima in the Izu seven islands in the Kanto region. Obsidian on Mt. Kozushima is said to have spread all over the Kanto region until about 3,000 years ago. Kozushima has never been connected to land even during the Ulm glacial period, so people needed a ship to get obsidian. 200 km was the range of daily exchanges such as logistics and politics in the Jomon period.
The Amano-Iwato myth is said to be a memory of a solar eclipse. However, solar eclipses are not so rare and do not cause any damage. It wouldn't be handed down as a myth. Imagine that the prototype was the eruption of the Kikai Caldera 7,300 years ago. Volcanic ash covered the whole of western Japan and probably covered the sun in the short term. West Japan is a region that would become the prototype of the nation later, and is also the place where the ancient affairs were compiled. The eruption of the volcano was not felt directly, but it is provable that a cloud of black ash would cover the sky. It was a large eruption that turned Southern Kyushu into a land of death, but although it caused disasters in distant regions, people remained who inherited the story. The myth peculiar to Kojiki is considered to be the memory of the Jomon people.
In the Jomon culture of Japan, we created a system that allowed people to settle down by collecting, hunting, and fishing. A variety of cultures and societies have emerged due to the natural environment of the region and each cultural tradition. A village was built at the Sannai-Maruyama site in Japan for 6,000 years.
About 3,500 years ago, the Han Chinese group arrived in northern China, oppressing the indigenous people in Yangtze River basin. The Han Chinese founded the Shang dynasty. The people of the Yangtze River basin spread to Japan, Southeast Asia, and Polynesia. Immigrants to Japan had different morphologies from Jomon people such as faces due to cold adaptation. The Yangtze River people brought the technique of paddy rice cultivation to Japan. The advent myth of Emperor Jimmu in Kojiki and Nihon Shoki seems as memory of this migration. Due to the civilization they brought, they moved to the Yayoi period. After the Yayoi period, migrants via the Korean Peninsula settled from northern Kyushu, moved on the coast of the Japan Sea to the Kinki region in Honshu. they repeatedly mixed blood with the descendants of the indigenous Jomon people and became mainlanders. However, the descendants of the Jomon people in Hokkaido were separated as Ainu people after almost no mixed blood with the migrants. The Ainu are likely to be mixed with the peoples around the Okhotsk Sea. The Ryukyu people in the Nansei Islands, centered on Okinawa, were also a unique ethnic group mixed with the ethnic groups of the southern islands. It is not as clear as the Ainu because of the large number of immigrants from the mainland since the Warring States period. They retain the characteristics of the Jomon people more strongly than the mainland people.
Japanese and Korean are Paleo-Far East Asian languages and belong to the Altaic language family. There is a language similar to Japanese in the Tamir region of South India. In addition to the language system that the Jomon people had, Japanese was formed by incorporating words that entered via the Korean Peninsula. The historical era of Japan began with the import of Chinese characters in the 7th century. The import of language is also the import of culture. Japan was strongly influenced by the Chinese civilization. However, due to the wars in China and the Korean Peninsula, trade was often closed and the sea was separated, forming a unique culture.
From the latter half of the Muromachi period, the Japanese shogunate and Fudai Daimyo traded and made huge profits. The disorder of the balance of power against the background of the profit caused the Onin War, which in turn caused the Warring States period. The Tokugawa Shogunate, which ended the war, banned the free trade of Japanese people for several reasons and adopted a so-called seclusion system. The direct reason is the prevention of Christian missions. Christianity was the first powerful religion since the introduction of Buddhism. In addition, as missionaries brought in their own colonial policies, diplomatic relations were abolished with Spain and Portugal, and other Catholic countries. In addition, big trade would flourish commerce and industry in the daimyo area and wealthy commerce. If they would become huge, there would be a risk that the shogunate would be relatively weakened. There, trade was controlled and foreign information was monopolized by the shogunate. However, instead of closing the door completely, information was actively gathered, and officials of the Shogunate were dispatched to investigate if necessary.
The Edo Shogunate at that time had world-class military power, so it was able to adhere to its own policies toward other countries. Although China and Korea could not be as thorough as Japan, they adopted a seclusion system to stabilize their countries. At that time, many of Japan's imports and exports were munitions such as raw materials for gunpowder, and weapons themselves were also imported. Since the Taiho Code, cows and horses have been valued as a means of production in Japan, so it was forbidden to slaughter them just for leather. Leather was imported in large quantities from Southeast Asia. A few necessities were imported through the Netherlands.
Until the Edo period, Japan was the world's largest producer of gold, silver and copper. According to Arai Hakuseki's Oritaku Shiba no Ki, in the latter half of the 17th century alone, there produced 2.4 million gold, 370,000 pieces of silver, and 70,000 tons of copper. Since gold was more abundant in Japan, the exchange ratio of silver and copper was different from that of other countries. As a result, foreign exchange trading was active, and one-quarter of domestic gold and three-quarters of silver flowed overseas.
I made summaries on the history of human beings every 500 years, focused on way of thinking. Current human beings were born in Africa approximately 200,000 years ago. We stayed in Africa a hundred and several tens of thousands of years, we spread to the continents of the Earth. Since the climate has warmed up, we established agricultural technology (10,000 years ago). We invented the use of letters and metals to create cities and comunities (6000 years ago). Technology and knowledge have been accumulated and systematized in the state (2000 years ago). People explored knowledge and skills and organized the wisdom they got. And modern scientific knowledge was highly organized (200 years ago). It can be said to be a period of great revolution.
Through these times, human beings have not changed as species. There is no big difference in intelligence. Therefore, the human who went south of Indian continent 30,000 years ago, the Dravidian warrior who faced the invasion of the Aryans 3,000 years ago, the merchant of the Mughal Empire which had traded with the British merchant 300 years ago, an Indian physicist who observes the fate of elementary particles by driving a synchrotron, all belong to the same species.
Since all human activities are never preserved, we cannot deny a possibility of existence of the destroyed civilization. During the history of human beings of 200,000 years, if it allows a time of progress for only 5000 years, there is a possibility that some people built a civilization of 200 years ago somewhere on the Earth. However, when becoming a civilization of the modern level, even if it would have been destroyed for some reason, its footprints cannot be completely erased due to a big change on the Earth. Therefore, I can conclude there was no civilization existed in the past at the same level of contemporary one.
The influence that human being exerted on the Earth is more abrupt than the change caused by living creatures before the human race, crustal deformation, and meteorological phenomena. In the earth history, it took thousands of years for the grassland to become a large forest. In addition, stable forests will continue to exist in the order of tens of millions of years. Human beings plant trees to convert the grasslands into forests in hundreds of years, and conversely turn the large forests into grasslands (ranches) in decades. The biosphere cannot keep up with the environmental change caused by human activities, so to speak, the extinction of species in present days is equivalent to the mass extinction in the past.
Since mankind has invented agricultural technology to control natural energy circulation, they have created their living area in the ecosystem on the Earth. Understanding of the natural world is indispensable for maintaining their living area. Since the method of understanding has shifted from religion to natural science, human beings have become able to expand their living area more efficiently. We have maintained the living area by scientific principles, only about 200 years ago. However, the change is rapid. The values of scientific civilization have already entered the period of comprehensive evaluation.
Until now I have described along the flow of history, but as the information volume becomes enormous as approaching the present age, it is difficult even to summarize. The history in the world is usually described as the history of politics, therefore the history of the war between the states. Politics is treated as small as possible in this thesis, and instead chose the foundation of contemporary civilization as a topic. I will outline as the development of basic technology in each field of energy technology, chemistry, agriculture, medicine. After summarizing the history of war, I will look at urbanization, democratization, the Internet which is the result of complex technology. Then I will look at the 21st century as the near future and conclude with a summary of the future of the Earth.
Perhaps in 95% of the time since the human race was born, the main power source was human. Thousands of years ago, we got more power when capturing large mammals such as cattle, horses, or buffaloes, into human society as livestock. Livestock has greater output than humans, but rearing management of them is necessary, and control of them is difficult. Humans were still necessary as power sources. Large mammalian livestock was mainly used as a means of transportation, and it also became food.
Next, a water wheel, windmill, and sail were invented. A description on the water wheels is preserved in Greece around the 1st century BC. I could not find the oldest windmill, but it will be in the same time and area as the waterwheel. A power unit that uses natural energy saves human labor in a simple operation for a long time. However, the amount of water in the river or the wind was influenced by natural conditions, and there was a defect in the stability of the output. Still, they became widespread, improved and used around the world until steam engines, internal combustion engines became common.
Steam power was put into practical use in the 18th century with the change that parts of various machines became iron. In the early days of the Industrial Revolution, steam engines and steel industries fueled wood. Eventually, when the forest decreased, the fuel turned into coal. Especially in the UK, there is a large vein of coal and iron ore, and two resources are tied together. An inventor, Mr. Watts improved the steam engine and put it into practical use. After that, it was incorporated into a steamship, a steam locomotive. Coal was used in coke furnace for ion manufacturing, production amount of ion increased at a stroke. Steam power was available even without river and wind, so we could make factories even in cities. We were able to consolidate production activities as factories by supplying power in cities.
In an agricultural society, we can barely make foods we eat, but there is little left to feed others. Therefore, very few people have extra energy to build castles, coats, and armor. The use of cows, horses, wind and water produced a small amount of surplus energy, but not much. The Industrial Revolution has dramatically increased the amount of energy per worker. The surplus energy has built houses, machines, software and tools that enrich our lives today.
The power plant is basically an energy conversion device. The windmill transforms the kinetic energy (wind) of the air into rotational motion of the shaft. Water turbines also convert the positional energy of water into kinetic energy. The steam engine converts (burns) the chemical energy of fuel into thermal energy, creates steam, and the controlled expansion of steam is converted into kinetic energy. The internal combustion engine explodes fuel in the confined cylinder and transmits the expansion energy to the piston. That is, the chemical energy of the fuel is converted into the kinetic energy of the piston for use.
An internal combustion engine has put into practical use in the latter half of the 19th century. It was a power technology that can be downsized and lightened by integrating the combustion part and the engine part. Internal combustion engines have been applied to various applications. Especially automobiles and ships have developed as transportation power. We have changed the trade of the world while infrastructures were prepared such as arranging roads and gas stations, and large harbor, Suez Canal, Panama Canal and so on.
At the same time, an electric power generator was invented. Wind power, hydraulic power, steam engine, and internal combustion engine are also used to turn the generator, converted to electric energy to be used. Nuclear energy was also added in the 20th century. Electric energy requires initial investment in infrastructure such as transmission line, but because of its low cost of transportation, small size of power plant, and high safety, it has spread rapidly.
Furthermore, batteries and accumulators that store electric energy in the form of chemical energy have been developed and spread. Batteries and accumulators are convenient to carry because they do not have to be connected with generators and transmission lines, further promoting device compactness. At present, fuel cells are being developed that directly convert chemical energy into electricity without burning.
Electricity travels through the transmission line, but it also travels in the air as electromagnetic waves. The technology which sends information as electric waves (radio waves) to a long distance via a transmission line or atmosphere accelerated the handling of information. It was 1890 that a submarine cable was laid between the UK and India. After this the submarine cable extended to China and Australia.
The international specialization supported by transportation and telegraph technology is a structure of the world history created since the era of the great voyage. International division of labor has developed in the form of supporting the industrial society of Western countries and promoted colonization of Asia and Africa. Conversely, after the Great Wars it became a driving force to raise national consciousness of each region.
The research theme of natural philosophy is matter, life, and prediction of future. Natural philosophy is trying to understand the material world, including physics and chemistry. To clarify the fundamental principle of the material world, for example, it was thought that gold could be produced. Alchemy is a technique that turns a substance into a more complete existence. Likewise, a medicine to change the human body into immortality was sought. In the ancient nation it was called an elixir. An anecdote of the Chinese emperor is famous. Medical arts for explanation on complex life phenomena and to improve the pathological condition were born in many civilizations. Astrology was established as an academic exercise to accurately predict the future with the movement of the celestial bodies. The idea that ordered motion of stars would be in conjunction with the movements of this world has brought about the concept of time to humans. It also became the basis of fortune-telling that the future is implied in various forms.
After Kepler, Galileo, Descartes and others, Newton introduced mathematics as a language to describe the law of dynamics, thus physics separated from natural philosophy. Physics is a discipline to explain natural phenomena by utilizing the results of mathematics. By using mathematics, we could explain nature more deeply, not limited to the phenomenon of real world. Moreover, it gained a calculation method which is convenient for application. The idea that celestial movements are mere physical laws has driven astrology into superstition.
On the other hand, the natural philosophy on objects and substances has developed another way. The medieval alchemist accumulated extraction techniques of various materials and created the foundation of chemistry. Gas is generated when mixing acid and metal. Hydrogen was discovered because the gas generated by the reaction of acid and metal is different from air. In the second half of the 18th century, gases such as nitrogen and oxygen were discovered one after another. By quantitatively analyzing the weight of the reacting substance and the weight of the products, it became clear that there is a certain proportional rule in the chemical reaction. The law of conservation of mass was proposed by Lavoisier, the concept of elements, atoms, molecules was also organized by Dalton.
At that time, the European countries expanded their forces and explored all over the world and gathered samples from the natural world such as animals, plants, and minerals as specimens. To record information such as the type and nature of specimens, and further to classify them is called as "natural history".
In the 19th century, the chemical reaction of matter was understood by combining atoms and their bonding, and various chemical reactions were discovered. Searching of elements began and the results were summarized as the periodic table. Also, synthesis and extraction of new molecules were carried out based on the list of chemical reactions. Chemistry is characterized as the science of understanding by the concept of molecules the myriad materials themselves existing on the Earth and the Universe, and the world where materials and life are interwoven.
At the same time, the chemical industry has spread all over the world. At first, pigment was synthesized, then explosives (such as dynamite) were synthesized. With knowledge of chemistry, it is possible to create substances that do not exist in nature and use them for industry. Chemical reactions were examined more comprehensively with accuracy far beyond by alchemists. Among them, a new industry that produces convenient substances for industries was born, and it was alchemy in literally.
In the 20th century, molecules constituting the living body were added to the analysis targets. In 1907, the world's first synthetic plastic "Bakelite" was born. Also, in order to explain theoretically the interaction of molecules, physics was introduced into chemistry, and a boundary science called physical chemistry was born. One representative product of this new area is a semiconductor that is the basis of electronics technology.
It is not too much to say that our civilization is supported by chemical knowledge. Many of the things directly and indirectly used in daily life have been obtained from the results of synthetic chemistry, from petroleum products, medicines, chemical fertilizers, semiconductors, iron, cement, plastics, synthetic fibers, cosmetics and stationeries.
Mankind has used various living organisms, plants and animals that grow on land and oceans as well as invisible microorganisms. Living organisms are nutrients for maintaining our lives and activities, and resources that support and enrich daily life. We have chosen a biological resource from the natural world that meets the purpose of our usages through long history. In addition, we have kept them close to us, selected desirable properties, and breed. At the same time, we have developed cultivation methods and breeding methods that maximize the ability of these living organisms.
The method of breeding depended on experience. The nature of the parent is inherited to their child or sometimes not. In order to ensure stable harvest, we have bred strong crops against cold climate or pests. Mendel revealed that genetic elements behave as independent units mathematically. The units are named genes, and the chemical substances is called DNA. Genetics has extracted useful traits from a vast breeding collection and helped to fix advantageous genes (to produce breeds).
Basis for breeding of rice and wheat was founded in Japan, and new varieties of corn was commercialized in the United States. Rice and wheat are dwarfed. Plant nutrition is made by photosynthesis. It is a breed that reduces the amount of limited photosynthetic products to distribute to root, stem and leaf growth and distributes as much as possible to the grain. The allocation to grain has been raised from 20% to 50-55%. At the same time, because of its low height, it became resistant against the wind not to fall down even if the crops were heavy. It is suitable for automating harvesting. For healthy growth of plants, enough roots, sufficient leaves for photosynthesis, and sturdy stems are required, so modern dwarf species is considered to mark the upper limit of harvest index.
In 1840, Liebig of Germany discovered that the inorganic components required by plants are carbon dioxide, water, nitrogen, phosphorus, and potassium. Nitrogen, phosphorus and potassium could be supplied from the ore, but nitrogen (nitrate) was also a natural resource derived from feces of birds and was a material of explosive, so it was sometimes in short supply. A method to chemically fix nitrogen in the atmosphere was developed from the beginning of 1900, and in 1913 the German company BASE developed a technology to mass-production of nitrate industrially. The technology of nitrogen fixation also allowed the mass production of explosives, so it is considered to be one of reasons why Germany took the World War I. It became possible to perform nutritional supplementation by chemical fertilizer artificially that relied on soil microorganisms. After World War II, chemical fertilizer was produced in earnest. It was said that the gunpowder factory was turned into a chemical fertilizer factory one after another. In addition, herbicides and insecticides that kill and eliminate organisms other than crops were also put into farmland. These chemicals promoted grain growth and minimized wear damage.
When reclamation is done with civil engineering machines equipped with power and cultivation is done by machine, hard labor which had been dependent on the power of livestock and people until then has become unnecessary. In addition, construction of dams and agricultural canals by civil engineering machines make it possible that meadow or forest were used as cultivated land. Groundwater was also pumped up by the power plant and it became available as agricultural water.
Giving chemical fertilizer to new varieties that grain harvesting is large and is difficult to collapse, further reclaiming and cultivating using large machines, the world grain production amounted to 2-3 times in this half century. Together these three technologies are called green revolution.
As a result, food and living goods are overflowing around us today. However, on a global scale, conversely the increase in food production causes an increase in population, and food production is unlikely to catch up with population growth. Excessive use of water resources and cultivated areas simplifying complex ecosystems cause deterioration of the global environment and destruction of ecosystems.
Advanced countries have spread agriculture using chemical fertilizers and agricultural chemicals, and assembled developing countries into the world market. Developing countries prioritize the production of commodity crops such as coffee and cocoa to acquire foreign currency, and are forced to import grain for their life. In addition, traditional agricultural production is declining, a lot of farmers are produced with full of dissatisfaction with liabilities. The seeds of traditional edible plants are decreasing. Genetically modified crops (GMOs) are being alerted by developing countries as they strengthen agricultural and economic control by advanced countries.
Until the 18th century, scientific advances were hardly seen in medical technology. In the nineteenth century, great progresses have emerged in medical technology. One is safe surgery using anesthetic and disinfection technology, and the other is the development of vaccine.
As for anesthesia, there is a description saying that Hua Da, a doctor in the early 3rd century in later Han dynasty, performed general anesthesia using Mandarin (Korean morning gloria, thorn apple). The Mandarin contains chemical substances with strong sedative action called scopolamine. Since side effects are also strong, it was not used in general. Anesthesia as a medical technology was established in 1804 by Hanaoka Seishu in Kishu. He devised how to use Mandarin, improved efficacy and reduced side effects. Anesthetic effect of chloroform and ether was also found in the 19th century. It is easy to obtain because it can chemically be synthesized easily. However, the effect is not sustained, so it is necessary to control the amount of inhalation, side effects such as liver disorder. Nevertheless, the anesthesia method significantly reduces the patient's burden in surgical operations and raises the success rate of surgery.
Large injuries are often suppurative and fatal. For the treatment of suppuration, the affected part was incinerated with burning trowel to arrest bleeding and to prevent infection. After we understand the cause of suppuration is microbial breeding, in order to remove microorganisms as much as possible (disinfection), we wash hands before surgery and treat instruments and bandages with hot water. Also, chemicals to disinfect the wound have been devised, and the wound wrapped. The times of the discovery of pathogenic microorganisms was the same time as damage by battle of soldiers became worse, because large firearms such as cannons were used for war. The surgeons at battlefront decided to try the disinfection technique on the field to prevent suppuration of the wound.
Pasteur denied experimentally the theory of spontaneous microbial generation around 1860 and proved the presence of environmental microorganisms in air, water and soil. He thought that microorganisms cause rot and disease. In 1885, he developed a rabies vaccine. The idea that some diseases are caused by infection with microorganisms has become the basis for development of disinfection and sterilization methods. Many microbiologists have studied pathogenic bacteria causing gangrene, septicemia, puerperal fever and isolated as pathogenic bacteria. The first vaccine is smallpox vaccine (1796) by Jenner. The vaccine is a drug that makes animals resistant to infectious diseases, and surely confined epidemic infections. Especially in 1980, smallpox who was an enemy of human beings for many years was eradicated by the spread of vaccine.
In the 18th century, the number of dead by war was those who died from infection overwhelmingly more than those from attack. The control of microorganisms by disinfection and sterilization enabled drastically to decrease the dead. In 1804, Mr. Appert invented canned and bottled food. The army adopted them as a portable food, then infectious diseases such as diarrhea drastically decreased. Still, the pandemic influenza epidemic in 1914 was raging in soldiers gathered for the World War I, and killed 20 million people worldwide.
Many drugs were discovered in the 20th century. Antipyretics, analgesics, anesthetics have advanced rapidly to be more effective and with few side effects. Using such as antibiotics, anesthesia and blood transfusion, surgeons began to perform complicated surgical procedures such as cancer resection, heart surgery, or organ transplant. In particular, the power of antibiotics is enormous, dramatically improving the survival rate of newborns. In about 1950 when antibiotics were popularized, baby-boomer generation was formed in advanced countries, and distortion by age occurred in the population. In addition, antibiotic-resistant bacteria have been selected and have been shown to cause infections, especially in hospitals that use large amounts of antibiotics. The development of new antibiotics has not caught up with the emergence of resistant bacteria. Modern policies have been taken to use as few antibiotics as possible.
When the control of microorganisms that killed a lot of people was almost completed, the next target of medical treatment became cancer and lifestyle diseases. While microorganisms are foreign enemies, cancer and lifestyle diseases can be said to be internal enemies. Human beings have changed their lifestyles to self-manage their bodies and spirits for healthy life. Due to progress in medicine, the culled genes in the past become preserved. A good example is myopia.
Race improvement has been done empirically from a long time ago. Plato envisioned a dictatorship elite society dominated by philosophers. He insisted that the ruler should secretly arrange a desirable male and female union. It should make a choice by lot. In Sparta, the newborn was interviewed by the tribal chief and frailty was abandoned deeply in the mountains. In the Roman times, people with malformations and incurable diseases were thrown away from the cliffs. Babies unwanted in the medieval Christian society were abandoned in public places, normal children were sometimes picked up, but children with disabilities were left alone. Since genetic analysis is possible in modern times, such screening is possible not only by phenotype but also by analysis of potential genes.
As a reference, epidemiological factors of high risk are opened in modern times. Low body weight, dangerous sexual intercourse, high blood pressure, tobacco, alcohol, dirt drinking water, hygienic hazard, high cholesterol, indoor smoke from solid fuel, iron deficiency, obesity, zinc deficiency, insufficient intake of vegetables, lack of exercise, Job injury risk, lead exposure, illegal drugs, infection with needles, not taking contraception, childhood sexual abuse (WHO, 2002).
In the 18th century, the Asian empires gave priority to stabilizing internal affairs against economic growth. On the other hand, the Europe countries began the political competition. The war between European countries has intensified by colonization of the African and the America where civilization was delayed. In addition, European countries has advanced to and promoted colonization of the Asia using the wealth gained on both continents. The European strengths that gained vast colonies led to the world wars.
Spain and Portugal were the first to win hegemony. Spain lost the naval battle with the UK and then declining. The UK got Africa, India and advanced further to the East. Meanwhile, the Netherlands and Belgium enhanced economic power with a focus on trade. France has advanced to North Africa, Russia and Austria robbed territories from Ottoman Turkey, whose power has declined. In addition, Russia acquired Siberia and advanced into the Sea of Okhotsk and Alaska.
Because the national state was established in France, it was attacked from the surrounding kingdom. Napoleon led the national army as a military, and removed their interferences, swept across Europe with its aggressive war as its mission. Other European countries had sense of crisis against the power of the national military. They also became national states one after another and had a national military.
On the other hand, the United States became independent from England. Then the countries of Latin America became independent. The United States issued the Monroe Declaration, completely denying the stereotype that the new continent (Americas) equals colonies by Europe.
Capitalism is fully dependent in expansion and growth. Capitalism at the national level was adopted by imperialism, and compete to gather colonies. It was inevitable that the world war brought about just before colonization of most of the world. Austria and Ottoman Turkey were divided into racial nations after the World War I, and the Russian revolution took place. Although the capitalist economy temporarily rallied due to the recovery from the World War I, the world economy and politics became confused by the 1929 World Depression. Among them, a totalitarian state (planned economy) such as the Soviet Union and the Nazis emerged. Fascism was inevitable where the national state system was extremely promoted. Nazi Germany, Japan Empire, Soviet Union developed a powerful military force. As a result, World War II broke out. Beginning with the tragedy of Guernica, an indiscriminate attack on the city was instantly started. In the nation-state regime, when the nation decides to war, the people must fight unlimitedly.
After the World War II, Europe was exhausted. The two major power system established of the United States and the Soviet Union. The Soviet Union succeeded in industrialization by the planned economy which started from the World War I, and at the same time established a system of totalitarian communism. The influence of the Soviet Union dominated Eastern Europe, China and mainly the major parts of the Eurasian Continent. Meanwhile, the United States dominated global shipping by the mighty navy. The United States promoted the liberalization of trade by setting the disappearance of totalitarianism and colonialism as an international standard.
As a result of the two major powers being armed with nuclear missiles, direct confrontation became impossible. Two strong forces in the international community brought about waging war in each region. The Korean turbulence is its first, the Soviet invasion of Afghanistan is the last. Eventually, when the European society and Japan recovered their national strength, the Soviet regime became relatively weak and the economy of the Soviet Union began to stagnate. When the Communist party dictators became politically unstable, the Baltic States and Eastern Europe took a democratization campaign. Gorbachev accepted it, then the Soviet regime collapsed and the Cold War ended.
At the end of the Cold War the civil war has intensified in the developing countries that had been stable due to the balance of the two powers. The United States, who confessed the world police, were also criticized by international society for the two Gulf Wars. When the demand by the Cold war disappeared, low-cost firearms were offered all over the world and the cost of war fell. Many local conflicts with army frequently occurred. Several countries are in ambiguity between normal time and wartime in various places. Moreover, the destruction activity by terrorism was activated in these countries with blank of power force. The symbol event was the September 11, 2001 terrorist incident in New York.
When agriculture started, people settled and built a city. Cities are centers of power, information, and goods. City is suitable for persons with power for managing their belongings directly. In modern times, city is necessary to maintain high quality living environment economically.
When the power used in industry switched from natural energy to steam engine etc., the place of production began to move to cities. The people who were forced to leave their land moved to the city in search for the new industry. The city also has functions as a production factory and delivery center of labor force. Due to the large number of people gathered in a small area, the works in the city have become subdivided. Segmentation is a specialization, that is, a high skill is required as a professional. The City has been attractive for young people to test various talents. The city also welcomed the pure labor force that is not tied to local customs. Occupational differentiation encouraged the penetration of the monetary economy. The consideration for products and labor was exchanged for money.
In order to have a large population within a limited area and to carry out production activities, it is essential to provide an infrastructure to smoothly supply water and energy, and effectively to dispose of waste water and things. Since the 19th century, cities equipped with independent water supply and drainage systems separating water and sewer from rivers and canals. Internal combustion engines with coal as an energy source provided power around the city and were used for various production activities. Also, as the transport network by railway was improved, the city further developed and expanded to the suburbs.
In the 20th century, two energy sources further enlarged the city. It is electricity and petroleum. When electricity was supplied, the internal combustion engine was avoided because of the waste and exhaust gas. Instead, the motor was used as power. Motor can be further miniaturized than internal combustion engine. Besides production activities, it was used in various life situations. By using gasoline, small internal combustion engines similar to motors have become widespread. In particular, mobile machines and automobiles equipped with small engines were put to practical use. Thus, the roads were also maintained for automobiles at a high cost. The railroad is a transportation system connecting the stations, but the car is connecting the doors, which was suitable for free movement in a narrow area.
Cities gathered water, electricity and food from the suburbs, and discarded the waste in the vicinity. When various industries concentrate, services diversified, raising the productivity of the city. As the population density rises, economy of scale works on the construction of public networks such as electricity, water supply, sewerage and information. The city became more comfortable space. Today, the cities become higher strata and concentration to the cities is accelerating. According to UN statistics, half of the world population (about 6 billion (2013)) lives in cities. Furthermore, it is estimated that the world population will exceed 8 billion people in the next 30 years and urban population will exceed 6 billion people. In advanced nations including Japan, three forth are already urban population. Japan is considered to have formed an urban society throughout the country.
Japan is entering an aging society. As a remnant of the migration of population in the era of high growth, many cities still have relatively young generation. However, in the next thirty years, the age structure of cities rapidly catches up with those of provinces and the metropolitan area will become aging. The flow of rural regression is a topic now, but conversely in fact, the flow to the downtown area is larger by the generation that knows the comfort of the city life. In the future, elderly people will move to the city and young people to rural area.
In a long history, we have been working on nature and have chosen something useful and valuable for us. The produce was transported, processed and stored where needed. Wastes generated during the production and transportation process were treated properly. As the scale of production activities increased, there was more work to do and more labor management. Professional occupations using advanced tools developed and productivity increased through division of labor. We have created a mechanism to share the benefits of production activities, and have operated the organization and society. People have developed an attitude of working systematically in a hierarchy, and have arranged an educational system to create a career from simple tasks to complex administrative tasks. An employment relationship has been established to employ talented people as assessing their talent and knowledge.
From the 18th century, the industrial revolution shifted production facilities to a city where labor is easy to obtain. Managers increased working hours to raise sales. Thus, workers were forced to overwork. It is believed that 90% of the world's population was in enslaved state until about 200 years ago. Factory owners formed a wealthy class with landowners and traders, and became a driving force for democratization. In advanced capitalist countries, industrial capitalism expanded to absorb excess rural population. Over time, when the excess population was depleted, the real wage rate of factory workers began to rise, and the gap between labor productivity and wage decreased. With the transition to a democratic society in European society, workers went on massive strikes for human rights. Managers were also forced to consider the welfare of workers, and a labor union was formed to discuss working conditions with employers.
The industrial revolution began with the mechanization of a simple textile industry (light industry), then proceeded into a heavy chemical industry requiring huge equipment in the early 20th century (the second industrial revolution). Productivity has also improved significantly, but it also requires huge capital, accelerating the concentration of wealth. The Second Industrial Revolution, which began in the West, created a conveyor system of work. Before modern times, production relied on the skills of craftsmen. The skills were broken down into simple tasks and organized so that unskilled person could do it in a short period of training. As a result, the craftsman was incorporated into factory labor, and the character as an independent worker and the spirit of independence were also lost.
As the industrial structure changes, the occupational structure also changes. Labor has become an act of earning wages in exchange with providing physical and brain health. Before modern times, most people were engaged in the primary industry, but as the second and third industries became major of the economy, the number of office workers increased significantly. With the accumulation of knowledge and the sophistication of production technology, the capacity of society expanded further, and human rights protection was enhanced in the name of welfare. In the late 20th century, as cities and business organizations matured, occupations providing services such as restaurants, entertainment and leisure, and large-scale retailers developed.
As the monetary economy pervaded, daily life and life satisfaction became increasingly dependent on money. A loss of work means the end of life. Without cash income, education, securing of transportation, going to hospital for illness will be difficult. Because labor is tied to wages, activities that do not earn wages are neglected. The natural environment and social capital, which are not directly linked to profits, were neglected.
When people were incorporated into companies as labor, the communities and common sense that existed in each area collapsed. The local community is an active place for elderly people who have knowledge and experience so far, and at the same time, it is an education that provides the communication skills and sociality necessary for young people to become full-grown person by participating in local activities. In a society mainly consist of self-employed persons, it was possible to work in a community based on individual will.
The occupation was generally hereditary during the long history of humans. When the number of office workers in the city increased, hereditary system ceased. The job of a parent cannot be seen by their child in case of a salaried worker. The children were free to choose the occupation they wanted to be in the future regardless of their parent's work, and it became natural that their working area was also different from their parent. In other words, the number of people increased who work different area from where grew up.
In the past, physical differences between men and women limited the types of jobs. In a hereditary society, the ideal life cycle of women was the eldest daughter-in-law. The position of the second son, the third son's wife, was very low. Now a day, women's life cycles are also available for women to choose. Young women want to become full-time housewives due to the harsh conditions surrounding professional women. At the same time, women's social advancement also progressed through the work-oriented workforce.
In general, children repeat trial and error to discover what kind of actions they take to lead to mutual sympathy of emotions, and as a result, to make others happy and to make themselves happy. It is said that a system of morality that is shared by everyone through adapting their own desires to the desires of others. With the development of science and technology, humankind has gained, freed from the hard labor of the past, a foundation on which everyone in the world can enjoy freedom of choice and a healthy life. Furthermore, thanks to the benefits of ICT technology, everyone in the world can know that fact. It was the beginning of the 21st century.
Science and technology are progressing in relation to each other. The computer technology goes same for the advancement. Progress began with the construction of logic circuits by semiconductors. Integration of logic circuits progressed on the basis of technology to increase the purity of silicon. The etching process by photoresist technology enables fine wiring and mass production of LSI. Although only one operation unit of the semiconductor element does not produce much efficiency, the LSI can execute many operations at high speed. LSI can be miniaturized by integration technology, which is the greatest advantage of computer.
It became possible to temporarily record information as an electrical signal on the device. Software that analyzes and processes information is also recorded on the device as electrical signals. The operation of CPU is to read the software's instructions in order, then to read the information from the memory along with the instruction, to process it, and to output it to the specified location on the memory.
Electronic data cannot be accepted as it is by human senses. Therefore, the computer is equipped with a keyboard for inputting data, a pointing input device such as a mouse or a touch panel, and a peripheral device such as a display or projector represented as an image, a printer, and a speaker. Magnetic or magneto-optical recording media for exchanging electronic data have been in frequent improvement, and their miniaturization and capacity increase are remarkable. Also, electronic data can be sent and received by the communication device.
Because the function of the computer is largely plastic, there is a possibility that the specification may vary depending on the product or producer. This situation made social mechanism to unify man-machine and machine-machine interface. Specifically, it can be found not only in computer OSes but also in communication devices such as telephones and the Internet. The commonality of procedures and systems as well as the operation of equipment reduces problems that cannot be connected, reduces education costs, more people participate, more knowledge is concentrated, and finally, it created a positive feedback circle of concentration of capital and investment.
Some inefficiencies remain in computer function. Like the typewriter's key layout, there are actually more efficient schemes, but they cannot be changed anymore because they have become widespread. But over time, advances in hardware and software will reshape the standard. The rapidly advancing and versatile computer and communication technology has been restructured into the ICT industry, involving related industries.
Once communication of a large amount of numerical data and character data was possible at high-speed using a computer, a communication facility became common, and a system was created that could transmit data directly from one person to another. It is the Internet. Internet was originally a communication control technology that was born out of research on communication networks with multiple pathways, in order to be resistant to destruction due to war and so on. Because internet was a communication technology in both directions, provided free of charge, it quickly spread in the industry. A powerful communications network has emerged because cables and terminals have been put in place to transmit large amounts of data. The ability to easily carry out international communications in real time has created business opportunities.
Originally the Internet was a collection of links of information. It was a mechanism that stores information on the server and makes it available for free access. Processing is easy because it is electronic information. Not only text data but also images and sounds can be freely exchanged and stored. The Internet opened the journalism, information communication, and publishing, which were exclusive occupations, to the general public. Today's Internet society creates links by the keyword search. The Internet is the third cultural revolution after establish of letters and printing technology.
With the spread of the Internet, the notion of global standards and globalization dominated in politics and economy. When common means and procedures in the world come to produce benefits, goods, services, and lifestyles become more uniform and rational. Since various activities were provided on a common platform, competition was intensified and became social stress. In addition, there are international tensions in which developed countries use globalization to take over economic industries in developing countries. There are also flows that respect the diversity of ethnic groups, religions, cultures, etc. in anti-reaction to the Internet.
In major cities in the world, it became possible to access and communicate information using a portable computer such as a smartphone. You can use high-speed communication to access the server, where you can perform complex calculations, and download the results. Even if the performance of the terminal in hand is not so high, it is possible to obtain high-performance computer-like performance. Also, a large amount of data can be stored in the server and freely accessed by high-speed communication. This cloud technology has boosted the popularity of mobile devices.
As the performance of computers has improved, it has become possible to analyze a large amount of data stored on the net in early in 21st century. In addition, data generated worldwide can be analyzed in real time. The cost for accumulation and analysis of information has dramatically decreased. The large amount of data generated by performance logs on the Internet or image analysis is called big data. From the analysis of big data, the pattern of the action of the human network will be analyzed, and the society will come which various aspects of our status are recognized. The results are applied to our business and politics.
So far, I have overviewed the history. I understand the principles of change and assemble the flow of history then apply these principles to the future forecast. Humans live a life predicting the future. Prediction of the future is essential to consider where to invest money or one’s abilities for a stable life. There is a field that predicts the future by quantitative model calculation, which is called futurology, but such a quantitative approach is impossible for individuals. While referring to those research results, I would like to select the result based on the principle of change I have drawn. First of all, I show four principles.
(1) As evolution is accelerated by the transfer of knowledge from parents to children, evolution and progress are accelerated by the transfer of wisdom in the state and society. Human activities have spread to the global scale so civilization will no longer die only when global catastrophe occurs.
(2) In the capitalist economy, employment is the main means of wealth distribution. How to distribute wealth in the past has also determined the society. In modern times, ICT is the technical solution. The principle and technology to equally distribute the wealth obtained in the future determine the social structure.
(3) In the past, a successful nation has developed basic public infrastructures such as schools, public health, justice, and territory. In an orderly society, entrepreneurs, inventors, financiers, politicians, artists, scientists are active and develop new wisdom and technology. It was the king, the religious leader and the army who made the nation. Groups with power in the future will create society.
(4) Technology is overwhelmingly born of technology rather than science. In other words, not geniuses innovate, but the activities of many people innovate. Technology finds the inventor, not the inventor finds it. Technology evolves on its own, no matter who is involved. Technology automatically advances to adjacent possible areas, like the evolution of living things. There is no leap into the distant future.
Reports that warn of the future often contain two unimportant points.
One is overpopulation. The theory of warning for overpopulation is built independently of the actual world population. It may be a mere sense of crisis for the author. If there is a lesson, it is that global pessimism is usually wrong. The global apocalypse industry (the lobby groups, groups of subsidizing agencies) is funded by threatening the government. To avoid the pessimistic future of mankind, technical bureaucrats advocate various savings, moderation, isolation and restrictions on freedom. Be careful of the easy use of the vague pronoun "we" and the abominable word "must".
The second is geopolitics. The geopolitical point of view is European view and does not adequately address contemporary issues, including the America continents. Geopolitics holds on two premises. First of all, human beings organize larger units than their families, and they must be involved in politics in the process of organization. The basis is their loyalty to the organization that has been born. The second is that the character of the state and the relationship between the states are greatly influenced by geography. In addition to land routes, sea lanes are important in modern times, and it is also necessary to incorporate the characteristics of the information society. Geopolitics seems to be finally taking over naval strength. However, in the modern world where the Internet and space technology are greatly influenced by power, geopolitics seems to fall into visual field constriction.
Below, I will predict the history of the 21st century with year in a venturous manner. In fact, it has already passed 20 percent of the 21st century. The realistic predictions of "when" and "how" do not make much sense. It is important to know what happens next. Therefore, my prediction will become thematic history of 100 years (80 years), not be arranged by year. Actually, it is necessary for construction of prediction to arrange the events per decade. I will continue to make corrections in my next version upgrade (3 years later?).
In the 2020s, IC tags are attached to most goods and people (identification cards). Tracking data of things are managed as big data and analyzed to construct rational logistics. More than 50% of people in the world will be connected by mobile networks by 2030, reaching almost 100% by 2080. Communication data is extracted from the cloud data and is used by various industries until 2040. Then, the government analyzes the data about social welfare and happiness, integrates them. The cloud data are used for policy decision.
The amount of time decreases spent for works directly by human beings. People has a lot of spare time (life) to kill, so a killing time industry becomes major. For example, people enjoy the universal themes, which Hollywood currently handles, such as money, sex, and violence. The Hollywood model industry is emerging around the world and so many games are produced. Interactive games adsorb movies to become a virtual reality industry since the 2030s. It develops to an integrated industry that entertains many people all over the world.
Virtual reality technology digitizes human interaction. Rather, avatars are created to reflect real people and are used to exchange information in real time in audio and video in virtual space. Business trips by avatars combined with translation technology will be commercialized in the 2030s, thus learning of language becomes unnecessary. The avatar also reflects the individual's language skills and personalities that are not expressed in language. Until the 2040s, people use programs that customize the avatar's behavior in a positive way. As fraudulent incidents using modification programs occur frequently, it will turn into a technology that faithfully reproduces individuals by 2050. This technology develops into a movement to release key personal information publicly.
From the 2020's, education will be developed into ICT from advanced countries, and individualized education will be conducted using digital textbooks. Education is replaced with practical skills acquisition that adapts and contributes to social life from knowledge acquisition. Schools will be dismantled that keep children in the classroom for more than a dozen years, and that force them to sit in chairs and to follow instructions. Educational programs are selected for discussions with diverse values and for acting within different occupational groups. Global educational challenges are based on sustainable economic activity, a standard of living of $ 10,000 a year, respect for diverse cultures, and the relationship between ICT and real life. It will take a time until around 2080 that these educational reforms spread to African countries.
The rapidly developing ICT technology will face a serious crisis in the late 2030s. Large companies collect company secrets of other companies by computer viruses, and collect personal information and use it to advertise to individuals. This movement is developed at the national level, especially at military use. Many companies use computer viruses for information disturbance and stock price manipulation, and also for attacks for rivals, control of business customers.
The activities of corporations and individuals are recorded based on the principle of virtual currency. This record is a detail of education and actions taken through ICT activities such as avatars and is called Digital Self. In other words, it is collected through educational ICT and avatar ICT and linked to individuals or corporations. In the case of an individual, its tip may be implanted in the body. Since the information is managed by the blockchain, it will not be altered by other companies or others. In addition, the digital immune system protects individuals' activities in ICT. Digital Self will be standardized and will spread to each individual by 2070, starting from a corporation.
Digital self is applied to politics. Politicians are nominated by election, but approval for candidates is awarded from Digital Self. Politicians no longer represent political groups. The compilation of the opinion is completed on the web, and the politician works to determine the direction of the country or local government referring to the public opinion. This trial will gradually change its way from advanced countries, and some countries will adopt it in full swing from around 2050. In the early days, the public's influence on the political guidelines was exerted through the net, resulting in populism. Gradually emphasis is placed on political activities with a long-term perspective, and direct democracy will be realized close to an ideal. The size of the nation becomes smaller in order to respond to a variety of values of people, as the less cost and labor in political activities.
Digital Self will spread worldwide in 2060, expanding from politicians to corporate directors and administrative managers. Also religious groups and public corporations must introduce it. Meanwhile, criminal records and special addictions are also monitored. Offenders are permitted limited ICT activities. Electronic ID cards, watched surveillance cameras, online usage records, GPS information of mobile phones, etc. are used for restriction. Prisons will disappear in 2050 and will shift to restrict social rights of criminals in response to crime. On the other hand, the physiological reasons for many criminal acts must be discovered. Officers understand there are crimes and quirks due to the nature of human beings. The concept of action and responsibility of an individual's will is neuroscientifically elucidated, written into a Digital Self, and used to assess one's crime.
For publicly active corporations and individuals, they must open their Digital Self at 95% of their personal information by 2070. Otherwise, travel, transactions and credit cards are restricted by the law. Meanwhile, the general public usually open their Digital Self about 60%. Their lifes belong to each nation or group. Population change is calming down, and an independent person forms a society while disclosing personal information. Individuals are required to be selfish and to act fairly.
The technology that reproduces human intellectual activity as a software is likely to be developed around 2060. The contents of deep learning are analyzed, and the LSI that reproduces the deep learning as a hardware. This technology will save the global economy from the ICT global recession around 2040. Since the neuro LSI needs to combine software with learning, the computer has its own personality. It is the birth of an artificial brain.
The greatest challenges of the 21st century are freedom and bondage. There can no longer be a full-scale war that could cause enormous economic damage. Instead, terrorism and guerrilla warfare will take place frequent. Especially in advanced countries, the control against terrorism overcomes individual freedom so to strengthen monitoring systems.
The world population in 2001 was about 6.22 billion. The breakdown is 3.78 billion in Asia, 850 million in the Americas, 840 million in Africa, 730 million in Europe, and 30 million in Oceania. In 2100, the United Nations estimates that the world's population will be 11.18 billion, Asia will be 4.78 billion, Africa will be 4.47 billion, the Americas will be 1.21 billion, Europe will be 650 million, and Oceania will be 70 million. The peak of the world's population is expected to be around 2100. Within 100 years from now, the population of Asia and Africa will account for 80%.
Refugees by conflict will increase in the 2020s. As the EU closes its borders, refugees will flow into cities in neighboring countries. In the Arab countries, India, Black Sea coast countries, Latin America, and Africa, huge slums are formed in the large cities. In China, immigrants in another way from rich areas to rich coastal areas are increasing. The refugees and immigrants form slams around cities. The relatively richer of these cities travel to all over the world as secondary immigrants. Excellent foreign students represent such immigrants and form human networks among nations.
Custom-made medicine that uses individual genetic information for medical care starts in the 2020s. Hospitals turn from treatment to prevention. In 2040, preventive drug administration will be performed based on individual genetic information, and the drug delivery in each person will be available. As a result, many illnesses can be prevented and the value of the elder life will be noticed. In developed countries, retirement age is raised up to 75 years, since we can keep almost healthy until old age. At the same time the birth rate declines. Furthermore, high birth rate and low death generation (the baby boom generation in Japan) almost die in 2050s and the demographic become flat. In developing countries, economic success will lead to declining birth rates.
The financial failure of the advanced welfare nations starts around 2030. Japan will be the most aging society in world history. The most serious effect of aging is the increase in senile dementia. The care of the elder with dementia highly pressurizes the national finance. Murder-suicide caused by dementia emerges as a serious social problem. Euthanasia is legalized in each country in the 2040s. Population adjustment policies are promoted in developing countries. To lower the birth rate, the level of education is raised and women's advancement into society is promoted.
The middle-income group will gradually expand on a global scale. It will reach 2 billions in Asia in 2050. The middle class naturally seeks richness and stability. On the other hand, the elite are the norm for international activities. Internet society spreads mainly in big cities. The exchange of information using the Internet becomes a daily routine, and citizen will take organizational action. In an undemocratic nation, political movements will flourish. Rather than gathering and demonstrating, which are attacked by authorities, sabotage, denial and non-action are their main activities.
From around 2050, activities to explore various ways of life will be activated on the occasion of the collapse of the national finance. Many mini-states can stand because the operation costs of democratic states are lowered by ICT. Immigration is increasing and their movement is dominated by political philosophy, in addition to wealth and population distribution. In most countries, the welfare provided by national finance is minimized. ICT will reduce operating costs of insurance, finance, education and pension, which private companies can provide using expert systems.
Around 2060, some groups appear that opposes the management of personal information by ICT, and they form community at various regions in the world to establish an independent nation. These movements are also related to religion. Christianity and Islam promises believers to join the community. The religions make social activities mandatory, such as giving to disadvantaged people, and disseminate them. They provide concrete social actions such as solidarity, alms, dignity. They seek to harmonize local culture and religion, political tendency and scientific thinking. At the end of 21st century, conflicts between countries increase again, so that the conflict refugees increase.
In the 2060s, large profit-making companies lose their meaning. As mobile networks become more widespread, companies are turning from the top-down management to knowledge-sharing organizations using the Web. International division of labor will be mainstream, using the characteristics of labor and technology in each region and culture area, taking advantage of the fact that distance does not make sense for communication. Work will be packaged and linked with the education system. Then, the labor matching system is developed with reference to the individual's ability information provided by the Digital Self. As the barrier that separates the company from the external environment becomes thinner, the company is positioned as a place to own the funding and manufacturing hardware. 80% of the workforce is provided from the liquid market.
In 2070, 80% of the population will live in cities. In big cities of Africa and Latin America, urban environment improvement cannot keep pace with population growth. A big population lives in a slum. They are always suffered from instability, terrorism and civil war happen repeatedly. Cities consume a lot of energy and have a large environmental impact. Maintaining a clean and orderly city is expensive and requires a high level of education. As a result, cities in the West, East Asia, and the Arab Empire are becoming more compact. The minimum population and density that can efficiently provide services will be determined according to their own culture. For example, publicizing food such as meals and markets, or publicizing housing will be provided as urban services depending on the culture.
By 2080, the monogamy system based on nurturing child has become extinct. Based on personal information disclosure from Digital Self community, communal life separated from reproduction is the main marriage. A new type of family is sought on the point who will raise children.
At the beginning of the 20th century, population of about 90% was engaged in the primary industries, but in advanced countries today it is around 2%. The reason for this is the increase in production per capita. In the secondary industries, it is following the same path. The tertiary industries will follow the same path in the 21st century through ICT, expert systems and robotization. What comes as the fourth industry in the 21st century? In other words, what occupations do people get the right and money to share the fruit of production activities?
A candidate for the fourth industries is the network plus remolding industry. That is, it is an industry that maintains and renews all facilities such as energy supply, roads, buildings, water and sewage, based on information networks that are social infrastructures. It is an industry in which ICT and custom-made industries are combined. As a concept, there is also a fourth industries that targets person themselves. In advanced countries, the fourth industrialization will inevitably progress from around 2030.
The fourth industries are a maintenance-based industry so that inevitably generate no or little profit. Thus, the thinking of the economy changes to get the right to use each infrastructure in exchange of making a non-payout investment. Many companies will turn into the infrastructures to serve the people who have invested. People will provide their labor instead of cash as a source of investment. Overall, the fourth industries are shared infrastructures. The global transition to the fourth industry will proceed in the late 21st century.
Until 2030s, there are speculations by European and American businessmen and leaders who want to rebuild global economic growth that Asia as a driving force of growth, and also the governments of Asian countries want to continue to believe that the people are seeking it. In other words, technological innovation advances quickly in developing countries to catch up with advanced countries. Large-scale industries can be easier from starting than remaking. In other words, if a large-scale industrial system that has already proved success will be able to provide technologies and services comparable to advanced countries in a short period of time. On the other hand, in developed countries, it is not easy to invest in upgrading the existing manufacturing facilities and systems to the latest equipment.
Large-scale development takes 10 years from planning. Huge buildings, large-scale plants, and dams are good examples. National scale infrastructure development can be considered 20 to 50 years. Such infrastructures are highway network, railway system, water and sewage system, flood controlling construction etc. Let's apply this ruler to the currently focused project. Assuming the start of the project at around 2020, and it will be usable in advanced countries in 2050. There is a 10- to 50-year time lag in developing countries. Therefore, the current production plants in Europe and the United States will be replaced by production plants in China, Southeast Asia, Turkey, Mexico, etc. in the 2030s, and these countries will be the centers of the production next. By 2050, it will shift to India, South America, developed countries in Africa and central Asia. With this shift, each country develops its own IOT-equipped infrastructure, which promotes modernization.
In advanced countries that have lost production plants, infrastructure with complete IOT system will be developed. Typical examples include complete car navigation systems (transportation), super grid feed systems (energy), 3D printer using multiple substrates with global standardization of 3D printer substrates (custom manufacture). A complete car navigation system makes logistics unmanned, resulting in significant cost reductions. Sharing information among the power supply system and users make minimize energy consumption in the city.
The production of goods is vertically integrated by IOT and ICT, from the recycling of waste resources to the production and delivery. Similarly, food production is vertically integrated from fields and farms to packaged ready-made foods. All of these are converted to the fourth industries as shared infrastructure.
Custom manufacturing with 3D printers is designed to recycle waste on a zero emission basis. That is, the materials used in the 3D printer are carefully selected, which can be decomposed and recycled from the product into the materials at the waste disposal plant. Most household goods and equipment are manufactured with 3D printers and are easily disassembled, sorted and recycled at waste disposal plants. The 3D printer will supply almost all commodities, which are ordered the home center. Custom-made manufacturing based on renewable energy in small-scale and high-tech are the typical fourth industries. Small to medium-sized plants, robot plants are operated to support 3D printer production in various technological demands. On the other hand, current consumer goods are made by order in small-scale manufacturers and traded as luxury materials.
The custom manufacturing industry using these IOTs will be completed and operated with a delay of several decades compared to education using ICT, custom medicine, insurance and investment. The fourth industries are completed in the West by about 2050s and completed in China, Southeast Asia, Turkey, Mexico by about 2070s. It will be in the 2080-90 years in India, South America, developing countries in Africa, and Central Asia.
From a long-term perspective, the energy source supplied to the earth's surface is the sun. The rational goal is to build such a society where human beings can live richly only by utilizing the limited energy sources supplied by the sun. Until now, the state would take the initiative in guaranteeing basic goods and services, or in creating a mechanism for religious and philanthropic mutual aid. Basic Human Needs (BHN) will be politically defined in the 21st century, when economic activity can be measured on a global scale.
A big nuclear reactor accident occurs around 2030 in countries with significant economic development, such as China, India and Brazil. An international mechanism is proposed to treat the storage and disposal of radioactive waste, while effort is continuing to upgrade to safer reactors in the face of accidents. The international consensus will proceed very slowly. A technology will be completed around 2050 to supply electricity from the high energy radioactive materials. It spreads all over the world as a power generator because radioactive waste can also be used. The widespread use of this device results in scattering high energy radioactive materials to the city. Around 2060 when they are put into practical use, small-scale accidents often occur. As advances in improvement of the device and technology for handling, accident will lower to the same frequency as those by airplane by around 2090.
If China becomes to have a consumption style similar to the US, China's grain consumption will reach two thirds of the world's grain production in 2030, which is comparable to the current world supply. This scenario is unlikely. Instead, food protectionism will rise by 2030 and resource diplomacy will be strengthened. On the other hand, the area of cultivated land will not increase in the next 40 years. Further sustainable agricultural technologies will be studied, and the transformation from large-scale farms, which were the basis of the Green Revolution, to agriculture that suits the local climate, will progress. Global food production will increase by 2060, but it will not keep up with demographic expansion and food protectionism will continue. In Japan, food shortages will occur under the influence of food protectionism from 2030 to 2040, but the food situation will improve as the population declines.
Over the centuries, a large amount of metal has been transformed from underground ore to above-ground products. Cities are stockpiles of these resources. Once population growth ceases, the necessary metals will be supplied by recycling. The IOT realizes recycling as described in the previous industrial chapter.
Food shortage in the world peaks around 2050 - 2060. The price of corn is expected to be 1.5 to 2 times that of 2010, and rice and wheat to be 1.3 to 2 times. On the other hand, due to global warming, agriculture will flourish in high latitude areas. Food production is expected to increase due to global warming in the northern hemisphere. Incidentally, the Arctic Ocean route will be opened by global warming, and transport efficiency will be improved for countries in the northern hemisphere. In the latter half of the 21st century, animals and plants will be improved by genetic modification, and new plants and animals will be provided for food and so on. Genetically modified animals and plants increase production in areas not suitable for agriculture, such as arid and salty areas.
Depletion of fossil fuels will become more serious, but in addition to small nuclear power generation mentioned above, equipment to supply energy as gas by methane fermentation of biomass, hydrogen production by solar panels and artificial photosynthesis will spread. Not only hydrogen but also methane can be used as a fuel cell material in the 2030s. In the 2040s, new resource of biofuel will be added to current glucose-based materials, such algae. In the 2060s, technology to ferment any common plants to produce biofuels will be added. By the end of the 21st century, biofuels will be standardized as stable solid fuels to store energy. Miniaturization of the apparatus for converting solid fuel into electric power will realize the power supply in household units and office units. This technique eliminates the need for power lines and the large power plants used limited to special applications.
In the 21st century, water supply in the cities will run short as the cities become huge. The water purification system in the city will be devised as an infrastructure by around 2030 in cities in advanced countries. However, in the other cities, it cannot catch up the demand of water. Dams and irrigation facilities will be developed as infrastructure in developing countries, but they will not only change flow and volume of river water, but will also increase water temperature and degrade ecosystems. Moreover, in cities other than advanced countries, maintenance of the sewerage cannot catch up. These problems are gradually solved in countries around the world according to economic development and large-scale industrialization progress. In the latter half of the 21st century, urban sewage treatment, seawater filtration technology and drinking water technology will be complete.
Other than political refugees, refugees include environmental ones. The scale of natural disasters will increase due to global warming. The coastal area will be destroyed by typhoons and global warming. After 2030’s, the delta region of large river will often sink in East Asia and South Asia. Food protectionism also produces a large number of environmental refugees. Like political refugees, environmental refugees migrate across borders from countries with poor infrastructure. Disaster risk is increased by poverty. Many African environmental refugees are due to drought associated with overload of development. Refugees migrate to cities and form slums in. Environmental refugees occur frequently until around 2080, when the infrastructure of 80% of the cities in the world is well ready.
The time will come when the cost to generate new advancement is greater than the value generated. Benefits are consumed to resolve issues such as the resource depletion, the environmental pollution, the overpopulation, the extreme weather, and the loss of biodiversity. Governments of each country introduce the negative interest rate all at once to settle government debts, which spreads to general interest rates. At the same time, a large amount of currency is supplied to the market. This phenomenon is due to the saturation of development.
During the 2020s, China overtakes the United States in economic size. Western countries are forced to make their economy small as a result of the collapse of welfare finance. Economic policy is changed in the direction of maintaining the reasonably rich life of individuals in a small economy. ICT and IOT are fully utilized for this purpose. Although a large amount of money is invested in these businesses, they do not generate enough profits and, as a result, the conversion of monetary policy to negative interest rates gradually proceeds. Global investment moves from China to Southeast Asia and India.
East Asian countries have also made various advances in the scientific field due to economic growth, but truly creative research requires innovation that will overturn authority. In that sense, the Confucian society of East Asia, or the despotic political system of China, work negatively. In that sense, if the democratic system is maintained, science and technology will develop in India. India surpasses China by economic power around 2050s. Whether China and India can cooperate in Asia or not determines the good or bad scenario of the world. In the case of a bad scenario for China, Japan tries to establish an economic zone in mainland China (Manchuria, Mongolia) and in the Southeast Asia from the Philippines to Indonesia. In a good scenario for China, Japan takes an isolationist policy and becomes a neutral country.
From 2030, with the development of Southeast Asia, Asia has a larger economy than the EU and USA. In 2050, the world's three major countries (US, China, India) reach 70% GDP of the world. Economic power of EU, Japan and Russia is declining. The world economy will be blocked from around 2050. By block economy, energy resources, water resources (agricultural produces), mineral resources, intellectual property are managed. North America (including EU without Russia, maybe), EU, Turkey and the Islamic world, India, and China are formed. In the case that Mexico could develop successfully, Laten American regions may become independent.
In 2050, over-investment mainly on ICT will burden the national finances and large enterprises almost all the world, and the economy will stagnate. Huge risk management by ICT technology is introduced on a national scale to avoid bankruptcy risks, but the failure of the system causes the Great Depression to occur repeatedly, and the global economy is exhausted. In a downturn, it is not possible to increase work and to redistribute surplus fairly. If the unemployment rate remains high for many years, society will become unstable. Eventually, the government will issue deficit-financing bonds and start job guarantees. This trend begins in the EU and Japan, and spreads to countries with low growth rate.
Africa will only achieve high growth in the late 21st century, but will not succeed in nurturing middle classes. This final frontier will be the final stage of maturity in the world economy. International society makes a plan with a balance on the politics. The city's population will reach nearly 8 billion in the 2080s, becoming a political and economic center. Cities are limited to around 10 million people and spread around the world, especially in developing countries. There are around 60 in the advanced countries (eight locations in Japan), but over 600 are established in the rest of the world. Cities in the advanced countries complete urban recycling technologies on self-sustaining development. On the other hand, in cities in developing countries, the absorption of slum will gradually progress.
In the first half of the 21st century, short-term perspective dominates future decision-making, but in the second half, a useful social model will be developed that accurately predicts the benefits of 50 years ahead. As a result, world economy breaks apart from growth-based capitalism. Instead of GDP, new indicators with environmental indicator are used as economic indicators. This policy will be established in harmony with negative interest rate policy in the late 21st century.
Economic disparities in the international community also exist in the future. The movement to close the economic gap drives changes in the international community. This section anticipates the political and economic future, including war.
The democratization movement is the driving force of changes in the first half of the 21st century. A democratization movement occurs when the income of the people per capita exceeds $ 10,000. The autocratic government is defeated by the democracy movement or the country is disturbed by the civil war. The economic development of emerging countries and the anarchy by civil war are the situation of politics in the first half of the 21st century. In the second half, many countries chose the block economy, because of enclosure of natural resources using mainly on ICT. The new hegemony will emerge in the 22nd century.
China will implement a domestic tightening policy while suffering from the democratization movement. China tries to dispel domestic dissatisfaction with the United States, Japan, or both as virtual enemies. However, the economic stagnation and democratization movement will hollow out the power of the Chinese Communist Party. A bad scenario for the Chinese regime in the 2020s is the bursting of a bubble, the economic downturn, the hollowing out of Communist Party organizations, and the independence of local political power along the border. Each local power cooperates with the favored country (foreign capital) and is superficially obedient to the central government, but in reality it is to strengthen the control of the local government. A good scenario is to succeed in democratization and work with overseas Chinese in neighboring countries to realize the Neo Chinocentrism concept. In any case, one-party dictatorship cannot continue. the concept.
The United States reaches a turning point in the 2020s. Conservatives (republic party) who exclude immigrants temporarily become dominant. However, in order to maintain the vitality of society, in the 2030s, USA will accept immigrants from abroad again. As a result, high productivity is maintained. The driving force of the US economy is the maintenance of the global economy, that is, freedom of aviation and navigation is guaranteed.
The U.S. military organizes the latest robotized, unmanned combat formation unit. USA can dispatch troops anywhere in the world in four days. A networked army performs highly mobile operations while analyzing the latest information from space.
In the 2030s, China-US proxy war broke out in Indonesia. The aim is supremacy in Southeast Asia. At almost the same time, a proxy war between Islam (Empire) and China begins in Central Asia. In addition, China is in conflict with India, and skirmishes continue between them. Russia will continue to explore expansion routes into Eastern Europe and Central Asia.
All Arab countries lose their power due to low oil prices. Turkey, which has a Turkish-speaking area extending to Central Asia, leads the Islamic society and temporarily faces China. The Islamic society creates updated religious principles that incorporate scientific rationality, and eliminates the negative legacy of the 20th century, such conflict between Shia and Sunna. Islamic countries and Turkey build a cooperative system in the 2040s aiming at the past Islamic Empire (from North Africa to Ukraine Region). A loose community was formed in the 2060s and gradually spread throughout the world towards the 22nd century.
Civil war is likely to occur in countries where the average age in population is low (the young population ratio is high). Poor countries in Africa and South America remain poor in the 2050s. There is no national power to cope with climate change, and cultivated land is decreasing. The population increases in this area, reaching 3 billion by 2050. It is one third of the world population. If Mexico succcesses on a path to development, mainly with the returnees from the United States, Mexico brings Latin American countries together to form an economic zone independent from the United States.
In the 2050s, with the progress of democratization and economic downturn, economical block formations continued. In the poorest regions, such as Africa and Latin America, people choose the small nation rather than a civil war. A large nation is divided into small states due to the reduction of political costs by ICT and by the increase of immigrants and refugees, etc. A compact government was established. The homogeneity of race, religion, language and culture will build a nation with a big central city. Local and civil wars are repeated, and people are not tied to the old land, move to the new nation where they can accept the policies there. Homogenous nations make a block economy and put mechanisms in place to develop each other.
The influence of the United States will decline from the 2050s due to development of the block economy of the world. Robotic war between China and India occurs around the 2050s. After that, this technology is exported to Africa, and thorough eradication operation at a nation level using robots will take place in Africa from the 2070s. At the same time, terrorist attacks using robots will occur in advanced countries. It is proposed and implemented at the international conference to insert a robot three principles program that respects basic human rights in robot AI. It will take until the 2090s to spread over the world.
In the second half of the 21st century, even in the case of a bad scenario, China will go to reconstruction, play a reverse import of person with many contacts from abroad, and recapture East Siberia from Russia. China promotes a policy of harmony with each country, admit autonomy to races in the country, and take a policy close to the United States system. The driving force is 200 million Chinese living outside the country. The Neo Chinocentism will be established by the 2080s at the latest. Meanwhile, anti-Chinese movements in surrounding countries ranging from Japan to Myanmar will also begin.
The focus of the 2080s is on African countries that have developed economically but are politically unstable. A series of regional wars between nations led to the establishment of the African Charter in the 2090s, and Africa becomes finally politically stable. It is a way of dividing the present country into the number of groups claiming sovereignty, recognizing autonomy, and forming an economic maturation program to achieve competition and harmony. This model also applies to other unstable nations and regions.
The growth curve gradually rises, then goes through a short period of rapid growth, eventually becomes slow and flat, which is a sigmoid type of curve. Assuming that the short rapid growth era is the 20th century, the 21st century would grow slowly. Growth is expected to almost cease in the 22nd century. Growth is population expansion, economic growth and technological progress. The world population will be at a peak of around 10 billion at the beginning of the 22nd century and decrease 5 billion at the end of the 22nd century. This is because the expanded ages in 21st century will dye.
The upper limit of the number of people who can maintain a stable relationship is about 150. There is also a forecast that it will increase to around 500 people by ICT. Historically, about 500 members in a social group can be maintained as a cohesive community. This number has determined the size of the population for quite long time after Homo sapience was born. The tribes had a territory. Other people entering the territory were considered non-human and attacked. This is not only to humanity. An increase in population leads to an over-up of their territory, so the people start to fight each other to keep their territory.
The energy consumed by Japan in one year is about 2x10E19 J (White paper on Energy, Japan). Here, 10E19 means 10 to the 19th power. It is calculated as 2x10E11J per person. The solar energy received by the earth is 1.7x10E17 W / sec = 1.7x10E17 J (solar constant 1.4x10E3 W / m2). However, about 70% of them reach the surface of the Earth, so 1.2x10E17 J, times 3x10E7 seconds for one year, so 3.6x10E24 J per year, which is 1.8x10E13 (18 trillion people) when divided by the value per Japanese person. With this energy, the atmosphere and the sea move, it rains, and non-human organisms live. If the maximum value that human can use is 0.1%, it will be equivalent to 18 billion people. These numbers limit the volume of human civilization after the 22nd century.
At the end of the 21st century, the westernization of African countries completes, and the scientific civilization born in Europe in the 18th century was realized on a global scale. The population expansion pressure in China and India has calmed down in the middle of the 21st century, and the population expansion pressure in Islam, Africa and South America is coming to a close by the 22nd century. Japanese-style social ideas that use the results of scientific civilization are spreading to the world from the late 21st century. The points are three. The one is limited resources and land. The next is emphasis on the hygiene environment. Finally renew public infrastructure regularly and use sustainable resources. Named as the East Asian principle, this idea, together with scientific civilization, has become a global recognition that governs the centuries following the 22nd century.
The basic way to educate people on global awareness and to maintain it is entertainment. Music and art have tried almost every possibility until 22nd century and human being cannot create new beauty. Movies and animations are also integrated into the virtual experience, in which art and music are already incorporated. The entertainment can provide an infinite combination of history, culture, philosophy, and so on, to people. There is no new beauty or value, but people cannot meet all the combinations in his/her lifetime, so it is enough for each person. Conversely, through entertainment, humanity will have a global awareness, which will be the basis of all humanity's psychological empathy. Entertainment favored will change by the cycle of short-term climate change and environmental change, so global awareness will sway for some extent but not significantly.
Human value originates from recognition that human beings are living things. This is an act of cutting out and ordering things that are important and valuable for survival from the world. Thus, the important idea is risk management. For example, health issue and post-retirement welfare for each person, and social disasters, natural disasters, proper treatment of nuclear power and chemicals for society. In the 22nd century, it will be mandatory to eliminate automatically risks through the measurement of not only individuals but also various social, industrial, and environmental parameters and the creation of their databases. These are for personal health management, education, maintenance of social infrastructure, disaster countermeasures, etc. Large plants with complex controls gradually disappear. The computer that executes maintenance will also be a self-managed system. This is the concrete content of global recognition.
The development of technology has used living organisms themselves, but has also used the mechanisms of life in engineering. It is a field called biomimicry. In the easy-to-understand examples, the streamline makes submarine ships move so quickly in water, artificial joint structures with a high degree of freedom, and imitation of eye and ear structures. These are examples of biotechnology as a model. At the beginning of the 21st century, when human activity increased, biotechnology as a measure is being developed to maintain ecosystems. In the 22nd century, in order to modify ecosystems by genetic engineering, not only individual organisms but also sophisticated regulation of ecosystems that integrates them are modeled and applied. In order to efficiently introduce solar energy into the human society, we use genetically modified organisms. That is, to grow trees into houses and buildings. Medicinal products and advanced compounds are made by plants. Garbage disposal is recovered as a raw material using genetically modified insects, fungi and bacteria. Population density is higher in low latitude regions where solar energy is large.
The common goal of humankind is to survive. Risk management goals are set for children, grandchildren, and their descendants. Until the 21st century, survival and risk management were carried out at each national level, but in the 22nd century it will expand globally. In each of the countries divided into small nations in 21st century, the measures for survival of descendants that match the climate and culture of each country are reflected in the policies in each nation. Children are also properly educated on the principles for survival.
The earth's surface has gradually cooled since the Cenozoic. The present climate is a recovery period from the little ice period in view of a cycle of around 100 years, that is, the average temperature is rising. However, in terms of a cycle of about 10,000 years, it is the interglacial period, and after several thousand years it will come the glacial age, and it lasts tens of thousands of years. Given that, moderate global warming is rather advantageous for human society. In the 23rd century, attempts start to adjust the concentration of greenhouse gases in the atmosphere so as not to reach the glacial age with monitoring global temperature. It is a large-scale attempt to measure the degree of global warming from many indicators and feedback to the world production situation according to their values. The measures against cooling are introduced as the fourth of the principles supporting the global recognition (The limitation of the Earth, good hygiene and the society with recycling system).
Some data suggest that temperatures during the glacial period fell much in several years frequently, not constantly. Low temperatures for several years have a devastating impact on agriculture that relies on open-field cultivation. It also does not allow hunting and aquaculture in the same area. In other words, the current civilization dependent on the stock and infrastructure is in danger in such a glacial period. If the situation goes fast, since the 23rd century, such a glacial period-specific climate pattern would appear, and the global temperature would fluctuate chaotically.
Ways to control global production activities to counteract chaotic fluctuations are sought. On the other hand, agriculture will be indoors and fishing will be mobile. Some plant factories have already been put to practical use in the early 21st century. Mobile fishery is an industry that reduces the impact of climate change by growing huge floating islands on the sea surface and aquaculture while moving along the ocean. In addition, floating island produces shallow water in moderate climate. That is, it is a technology to bring out the richness of coral reefs to the vast ocean. Productivity of the entire fishery will also be improved.
Complete and disseminate a system to record and analyze all the senses and experiences of an individual's lifetime. People store the records on their living in the cloud database and analyze them with constant access. The deep learning will develop to a technology that reproduces the individual's brain from memory and choice-oriented data, which is left as software together with the personal experience record. Furthermore, in order to imitate humanity, application technology of neuro LSI that reflects ambiguity in hardware is established. The fusion of the two technologies allows people to live in the organic brain and have the option of transitioning to the silicon brain after death.
A copy of an individual's mental activity stored in a neuro LSI and sufficient memory space is continuously learned and maintained as an individual unless the power is turned off. By law, it is given legal personality and is called the AI legal person. AI legal persons are supplied with power and hardware by serving specific individuals (his/her descendants) or society. AI legal persons learn the ability to distinguish themselves from other personalities and behave like humans, but because the way they receive (sense) and output information is different from that of real humans, they develop as their own intellect.
Due to the global recognition that was born in the 22nd century, the decentralization progressed. Small nations are formed in each region, mainly in large cities, and the population of each nation is limited to 100 million. A small nation is united by language, culture, values, religion, and historical awareness, giving residents a sense of unity and security.
However, because of its diversity, a nation will emerge which prospers over other countries. At the time of the Great Depression in 1929, national socialism such as Nazi Germany, and the planned economic system of the Soviet Union had made exceptional progress. Similar experiments were conducted in Japan in the 1930s in Manchukuo. In case that each political entity operates a nation with diverse values, some nation will implement economic development systematically, and such a nation will have an economic advantage over other countries. If this country chooses the leader who gives priority to its own interests only, it may invade other countries.
In the world after the 22nd century, all nations avoid the exhaustion of the national economy due to armed conflict as did until the 21st century. Instead of fighting with physical weapons, it is an information war on the Internet. There is a war that rationally deprives the other's economic power and virtually conquers like a corporate merger. At that time, limited destruction activities such as cutting information lines and destroying artificial satellites are performed, resulting in damage to many countries. After a history of such unfortunate conquests and subsequent discrimination, the respect of other countries becomes a strong global recognition. In addition, incidents such as information blackout due to failure to repair information infrastructure often occur. Since the blackout accident also adversely affects the operation of many countries, the global recognition is strengthened.
Until the 23rd century and the next few centuries, long stable era will be realized except some fluctuations. However, the future cannot be predicted. The arrival of a catastrophe that destroys civilization is also possible.
The economic and political trends cannot be predicted 100 years from now. In other words, it is impossible to predict in chronological order. This is due to sudden historical incidents, such as natural disasters, new national leaders, discoveries and inventions in science and technology. When some powers in the world, for example, the state, large enterprises or religion, cling to capture the global market, the global recognition would weaken, the surveillance system over common risks would be broken and finally the civilization would decline. The neglect of the global recognition leads to destroy the human society.
For example, a selfish nation becomes aggressive to concur other countries. Since every nation already knows nuclear weapons, it is possible to use them as a trump card against aggression wars. In particular, inferior countries are likely to use nuclear weapons. A nuclear winter was once predicted. The scenario in the 22nd century is plausible that wars occur in developing countries and about 50 atomic bombs are used. The dust generated by the nuclear explosion is rolled up in the sky, and staying in the stratosphere for a long time. It lowers the average temperature of the Earth, and inhibits the photosynthesis of plants. Being interrupted by solar energy is a matter of life and death for human beings living on the Earth. Human society is rapidly collapsing, and massive wars may occur over limited energy resources. Thirty millions of people died in World War II. It is around 2% of the world population at that time.
The Sunda Trench runs south of Indonesia. The Australian plate is subducting into the Eurasian plate there. Huge volcanic activity occurred here. Not to mention the Toba volcano 74,000 years ago, the large volcanic eruptions are known in 1257, 1815, and 1883. In these cases, the following year of the eruption, it was a cold summer in mainly in the Northern Hemisphere, and agricultural products were devastated. Social confusion of this scale can also occur in epidemics of infectious diseases such as the new coronavirus epidemic today. Infectious diseases that threaten human economic activities will continue to occur at a frequency of about once every 100 years.
Collapse of risk monitoring system. Autocratic nations reduce the energy and infrastructure needed for the risk management in order to prioritize their economic development. That is, they divert to their own temporary luxury. A surveillance system established by the 23rd century is a global network that monitors the threat from 20 km underground to 20 km above the Earth and several light years from the Earth. Massive volcanic activities and a fall of asteroid pose similar threats as nuclear winter. Management of global warming by controlling concentration of greenhouse gases in atmosphere is necessary for conversely prevention of cooling. It is unimaginable catastrophe more than the biggest war in human history.
A self-healing mechanical system is essential for risk management, and programs that perform analysis and prediction that cannot be calculated by human linear logic are already being installed in computers as the deep learning. Human beings use the neuro-LSI technology completed in the 22nd century to port individuals to hardware one after another and create AI legal person. They learn human society while communicating with a new generation of human beings, while developing science. At the same time, it manages a self-healing mechanical system that is out of control for humans. With this technology, some nations or companies will develop self-sustaining and self-replicating space ships and send them out into space.
Disaster risk never goes to zero. Some nations or large enterprises seek out prominent planets from nearby solar system explorations and implement plans to transplant humanity. The device is used to migrate Earth's life into space. Organisms will be carried by spacecraft as fertilized eggs, and the birth of the new world will be carried out by an evolved AI legal person.
A catastrophic change in the global environment that destroys homo sapience is scientifically predicted. Within a million years, it is the eruption of a giant volcano and the collision of an asteroid with a diameter of 10 km or more. The eruption of a giant volcano may exterminate homo sapience, but it does not destroy all lives on the Earth. On the other hand, in the collision of asteroids, if an asteroid with a diameter of 100 km collides, the life of the earth may become extinct.
There is another possibility. If a species with intelligence that surpasses humanity evolves and that species deprives humans of their living sphere, humans will perish. The species will be born from humankind. Its ability is beyond our imagination.
Large eruptions in Yellowstone National Park occur approximately once every 1.5 million years. The next eruption will be about 900,000 years later. The eruption of Toba volcano of 78 thousand years ago was the second size in the Cenozoic. Its frequency is estimated to be higher than the fall of meteorites of the same energy level. This class of eruptions is calculated 5 times a million years, which human would perish. When a volcano erupts in this class, summer disappears for several years, which has a major impact on life on Earth. Human civilization will also be devastated at least.
Collision of asteroids. If the diameter is 400 km, the ocean will evaporate and the Earth would be covered with rock vapor, and life will be wiped out. It will take about 2000 years for the sea to return to its original state without lives. If the diameter is 100 km, there is a possibility that organisms will remain in the deep sea. The diameter of the meteorite that is said to have destroyed the dinosaurs is about 10 km. If the diameter is about 1 km, it can be observed from the Earth and the orbit can be calculated. Mankind will monitor the orbit of such asteroids as long as it maintains civilization.
70,000 years ago, the red dwarf star Scholz's passed 0.8 light years from the Sun. It is now 20 light years ahead. Several comets have been affected by their orbits as a result that the star swept away the solar system. Grise 710 is a red dwarf star in the Serpent Bearer. This star travels toward the Earth at 25 km/s and reaches its closest point after 1.5 million years. It passes a distance of about one light year from the Sun and disturbs the orbit of a comet around the solar system. It is estimated that one star in every 10 million years passes the Oort cloud. The gravity of such star is the motive powers to change the orbits of various objects that travel in the solar system and as a result, new giant meteorite might direct to the Earth.
On average, unicellular organisms and plant species have existed as 10 to 30 million years, and insect species have existed as millions of years. The average life time as species of mammals is 1 million years. This value includes the five extinctions that have occurred in the past, but it may serve as a reference for human life as a species. It has been 200,000 years since the establishment of Homo sapience as a species. The average value implies that human beings will reach the end of life as a species in 0.5 to 1 million years after. Since the human Y chromosome is not corrected by recombination, it shortens with each generation and disappears after millions of years. Assuming that human beings are alive and maintain civilization by this far future, we will have established reproductive technology only by femininity.
The frequency of gamma-ray burst when black hole is produced is once every 100,000 years in the Milky Way Galaxy, but its impact travels over 1000 light years. Since the gamma ray burst is emitted in the form of beam, the probability of reaching the Earth is about once every 100 million years. This frequency is close to the cycle of great extinction of living organisms in history.
The continents are gathering towards Asia, and after 200 million years the supercontinent will appear again. The formation of new supercontinent will change wind and ocean currents greatly to affect the global climate.
The solar system moves up and down in the Milky Way Galaxy disk with a cycle of 30 million years. Therefore, it is getting closer to or away from the stars near the solar system. Supernovas occur in the Milky Way Galaxy at a rate of once in 50 years. The supernova explosion that affects the Earth is estimated to be less than 25 light years, so it is estimated about once every 700 million years. With this distance, precursors can be observed easily.
The Earth itself continues to cool, but the Sun gets hotter. After hundreds of millions of years, the Sun begins to burn helium, whose nucleus heavier than hydrogen, and releases more energy than it does now. As the pressure in the center increases, so does the diameter of the Sun. The Habitable Zone, which can maintain the same environment as the present Earth in the Solar System, moves out of the Solar System with time. Warming of the climate accelerates the weathering of rocks, which make all carbon dioxides dissolve in seawater, then plant growth is threatened.
By the heat of the Sun, the sea on the Earth evaporates, and the Earth wears a water vapor atmosphere. The water molecules that have reached above the stratosphere escape to the outer space. Life consisting of organic matter will be destroyed. After 2.5 billion years, the atmosphere of the water vapor and the heat make balance, and the magma ocean covers the ground and stabilizes for a while.
Five billion years later, the fusion reaction of hydrogen in the Sun will end, and carbon and oxygen nuclei will be synthesized via helium. The central part of the Sun begins to develop degenerate pressure due to the increase in density. The Sun can exist stably against gravity even without a fusion reaction. Eventually, the fusion reaction ceases and the Sun becomes a white dwarf that slowly cools while releasing the energy stored inside. At this time, the gas on the surface, which swelled as a red giant, shook off gravity and was scattered in the interstellar space. The Sun loses about 40% of its mass. The Sun is about the same size as the Earth and is a dense star. The solar system becomes a beautiful planetary nebula by illuminating the material diffused around by the Sun, which has become a white dwarf.
According to researchers' simulations, the Milky Way galaxy will swallow the Large Magellanic Cloud in about two billion years. It will disappear forever from the southern sky. After that, the Small Magellanic Cloud will follow the same fate.
The Andromeda Galaxy (M31) and our Milky Way Galaxy are believed to collide 3 billion years later. The impact on the Earth is unknown. Because the stars in both galaxies are well separated, they merge so as to slip through each other's bodies. However, the stars are variously shaken and diffused by the gravity of both galaxies. An arm of one billion stars is cast out of the extragalactic empty space. After half a billion years, most of the stars coalesce and gather around the gravity well of the dark matters. It will take another billion years for the merged galaxies to become elliptical. The solar system will be thrown out of the outer space or will remain at the periphery.
Gas flows into the center of the newly formed galaxy, and intense star formation occurs. Many of the stars born at this time are massive stars, so their lifespan is short, and they immediately cause a supernova explosion. The explosions are so powerful that they blow away the discs around the galaxy. This period is estimated to be about 5 billion years later.
In the distant future, two galactic center black holes will merge. The stars that make up the Galaxy exert gravity and move, but sometimes interact to exchange kinetic energy. At that time, those who acquired kinetic energy move away from the center of the galaxy, and those who lost it fall to the center. The two supermassive black holes of the Andromeda Galaxy and the Milky Way Galaxy capturing the surrounding stars and become quasars. At the center of the new galaxy, two former Central Black Holes revolves each other, emitting strong gravitational waves. The new galaxy, which lost the disk that was the cradle of stars, becomes an old elliptical galaxy with little star formation. In the far distant future, the two central black holes will merge.
The universe continues to expand, but the gravitationally-linked super clusters are not dispersed. A star burns out in 10 billion years and becomes a red dwarf. Red dwarfs turn into black dwarfs and lose light after a lifespan of 100 billion to 10 trillion years. About 100 trillion years later, our Virgo super cluster have a huge black hole of 10 billion times the solar mass and countless black dwarfs scattered in the void. The super cluster moves away from the next at a speed greater than the speed of light, and all super galaxy clusters disappear beyond the horizon of the universe.
Black holes also evaporate slowly due to the effects of particle-antiparticle generation that occur at the horizon of event. Black holes will eventually evaporate due to the absence of the stars. The proton has a lifetime, and decays with a half-life of 10E33 years to become positrons and pions. Positrons annihilate with electrons, and pions also decay to gamma rays. Isolated neutrons decay into protons and electrons with a half-life of 10 minutes. This means destruction of atoms. In the universe, all atoms disappear and thermal death full of only radiation occurs.
