4.567 billion years ago, the Solar System was born. By 4.560 billion years ago, primitive Earth was formed, with subsequent creation of the Moon nearing 4.550 billion years ago. At the time of its formation, the Hadean primitive Earth was a dry naked planet, lacking both an atmosphere and ocean, and it was covered by an anorthositic primordial continent. 4.567 billion years ago : The formation of the Solar System. 4.56 billion years:ago : The formation of the Earth. 4.55 billion years ago : Giant impact.
During 4.37-4.20 billion years ago, abundant icy planetesimals bombarded the primitive dry Earth, which caused it to be enveloped by an atmosphere and an ocean. After the appearance of the ocean, plate tectonics started, but the ocean was too saline, acidic, and enriched in heavy metals. Life could not emerge in such a toxic ocean. 4.37-4.20 billion years ago : The formation of the atmosphere and ocean. 4.37-4.20 billion years ago : The initiation plate tectonics.
Primitive life was about to emerge in an underground cave of a nuclear geyser. An enormous amount of building blocks of life were continuously produced with the ionizing radiation of a natural nuclear reactor. Gradually, the building blocks of life were evolving into first proto-life through the form of an ectosymbiont.
4.37-4.20 billion years ago : The loss of the primordial continent and the generation of a strong geomagnetic field. The first proto-life, born in a natural nuclear geyser, was periodically splashed onto the Hadean surface environment, where they evolved into the second stage of proto-life which utilized solar energy to survive. However, they perished once exposed to the toxic ocean. Finally, after repeated mass extinctions, the third stage of proto-life emerged: the first prokaryote and ancestor of animals and plants which could survive the external environment such as toxic ocean.
2.90 billion years ago: The emergence of photosynthetic life. 2.70 billion years ago: Mantle overturn. The first photosynthetic bacteria were anaerobic microbes, which produced no oxygen. Through time, life developed the mechanism to utilize oxygen to produce more energy, recorded in the appearance of cyanobacteria. Around 2.7 billion years ago, due to the cooling of the Earth’s interior, the old slab of the primordial crust, which had been transferred to the bottom of the upper mantle by plate tectonics where it had stagnantly rested, collapsed to the lower mantle. Ensuring abundant mantle plumes ascended from the lower mantle to the upper mantle, a distinct event known as mantle overturn.
2.3 billion years ago: Mass extinction by snowball Earth. 2.1 billion years ago: From prokaryotes to eukaryotes. 2.3 billion years ago, the Milky Way Galaxy collided with a dwarf galaxy resulting in a supernova explosion that produced abundant cosmic rays. Due to the degeneration of the heliosphere, cosmic rays struck the Earth, promoting the formation of clouds which eventually enveloped the Earth Due to the thick cloud envelope, the Earth experienced global glaciation, called the Snowball Earth, which caused global mass extinction. However, some Prokaryotes survived the Snowball Earth to evolve into larger life as an endosymbiotic system. At last, eukaryotes appeared.
1.90-0.80 billion tears ago : The Formation of a Supercontinent. 700-600 million years ago : The Sturtian Glaciation 700-600 million years ago : The Leaking Earth. Free oxygen produced by cyanobacteria gradually accumulated in the atmosphere. When the soil covered the dead cyanobacteria, more oxygen accumulated and atmospheric oxygen dramatically increased. “The Leaking Earth" phenomenon that started about 700 million years ago further expanded both the land, and free oxygen in the atmosphere, resulting in the expansion of the habitat of life that led to explosive biological evolution.
640 million years ago: The Origin of Multicellular Life. The Marinoan Glaciation. 580 million years ago: Appearance of Ediacaran Fauna. The Gaskiers Glaciation. 550 million years ago: Evolution Responds to Environmental Changes. 540 million years ago: The First Cambrian Organisms. In order to survive the repetitive periods of extreme cold and extreme heat, life evolved into a symbiotic body of multiple lifeforms, and the Ediacaran and Cambrian fauna and flora emerged. In the evolution of these organisms, the Stem evolution occurred along the continental breakup area, which encouraged the creation of a new species. Meanwhile, in the continental collision zone, the Crown evolution progressed, resulting in the explosive diversification of species.
600 million years ago: Expanding Habitats. 540 million years ago: The Co-evolution of Planets and Insects 550-540 million years ago: The Evolution of Vertebrates 260-250 million years ago: The Largest Mass extinction of the Phanerozoic Eon. Collision with a Dark nebula In the early Paleozoic era, the salt concentration in the ocean had decreased to about twice the current level, and the habitat of organisms spread into the ocean. After vertebrates were born, they evolved over time from fish into amphibians, reptiles, and then dinosaurs and mammals. And, the co-evolution of plants and insects also progressed on land. At the end of the Paleozoic era, Paleozoic animals became extinct because of the collision between the dark nebula and the solar system.
Dispersion and amalgamation of continents, and the evolution of life. The birth of primates. The Mesozoic is the period when dinosaurs reigned at the top of the ecosystem. Stem evolution caused the emergence of new species where the continent split apart, while Crown evolution has led to species diversification through the amalgamation of continents. While dinosaurs spread throughout the world via this process, mammals were also born 250 million years ago, and flourished after dinosaurs went extinct. And primates, leading to the appearance of human beings, were born about 100 million years ago.
Evolution into primates. The birth of human beings, the fourth animal category : the Humanozoic eon. 10000 years ago : The Agricultural Revolution. 5000 years ago : The Urban Revolution. 2400 years ago : The Religious Revolution. 300 years ago : The Industrial Revolution. The Information Revolution. Human beings are morphologically a kind of primate, but we have invented science and civilization due to our very complex and highly developed brains. From this point of view, human beings can be regarded as "the fourth animal category", which is completely different from other life. The birth of human beings is one of the most significant events in Earth-life history, and we can regard this period as the Humanozoic era.
Challenges for Human society. Future of Human society. Future of the Earth. 200 million years later : Formation of the supercontinent. 400 million years later : Extinction of the C4 plants. 1 billion years later : Cessation of plate tectonics. 1.5 billion years later : Disappearance of the ocean. 4.5 billion years later : Collision between the Milky Way Galaxy and the Andromeda Galaxy. 8 billion years later : Annihilation of the Earth. Humans will eventually create self-replicating robots and go out into space. As a result of the fact that the Earth has been cooling since its birth, the depletion of surface ocean water will stop plate tectonics and turn it into a Venus-like planet. Then, about 8 billion years later, the Earth will be swallowed by the expanding Sun. However, by that time, Earth’s life has already changed and will have reached other galaxies as self-replicating artificial life.
