1. The first stage of the formation of the Earth's circle, 4.6 billion to 4.2 billion years ago. The material that formed the primordial Earth is mainly the primitive material of the nebula disk, composed mainly of hydrogen and helium, which account for about 98% of the total mass, and in the early stages of the sun's contraction and evolution, there are solid dust and material ejected, and in the process of the formation of the earth, due to the differentiation of matter, light matter is continuously separated from the volatile material of hydrogen and helium, and is brought to the outside of the solar system by the pressure of solar light and the material thrown by the sun. Thus only heavy or soil matter gradually thickened to form a primordial Earth, which was born 4.6 billion years ago when the Earth was composed of luminous spheres of hot liquid matter (mainly magma), and over time, the surface temperature continued to decrease, and solid nuclei gradually formed. Dense material moves toward the center of the earth, and less dense material (rock, etc.) floats on the surface of the earth, forming a earth with a surface composed mainly of rocks.
2. The second stage of the Archean and Proterozoic periods, 4.2 billion to 543 million years ago. The Earth continuously releases energy, and the water vapor, carbon dioxide and other gases released by high-temperature magma constitute a very thin early primitive atmosphere, and as the water vapor content in the primitive atmosphere increases, more and more water vapor condenses into small water droplets, and finally converges into rainwater falling to the surface, and the primitive ocean is formed.
3. The third stage of the Ezoic period, 543 million years ago. The duration of the Phanerozoic is relatively short, due to the flourishing of organisms, the geological evolution is very rapid and the process is rich and colorful, coupled with the extensive preservation of geological bodies throughout the earth, as the main research object of observation and research, laying the foundation of geology, theory and basic knowledge of geological science.
Life on Earth has undergone a long evolutionary process from scratch, from simple prokaryotic single-celled organisms to complex eukaryotic multicellular organisms, and the emergence of life on Earth has its contingency and inevitability. The early evolution of the stars in the Milky Way and the formation of the solar system gave the planet Earth a special interstellar position and material composition. The early environment of the earth is suitable for the emergence of life, and the activity of life on the earth also changes the environment of the earth. The environment is closely related to life, and the evolution of organisms is the result of the co-evolution of organisms and the environment. From the oldest known biological fossils on Earth, prokaryote fossils, primitive life originated between 3.5 billion and 4.6 billion years ago, while producing simple ecosystems, the emergence of eukaryotic life 2.7 billion years ago, the late Proterozoic to neoproterozoic, the early differentiation of multicellular and multicellular plants, and the evolution of complex ecosystems.
The emergence of biological multicellular cells is the result of the co-evolution of the early Earth environment and organisms. Cyanobacteria and bacteria were the main players in changing the early Earth's environment, and after they appeared 3.5 billion years ago, they occupied nearly 2 billion years of Earth's life history, cyanobacteria and bacteria formed, and microorganisms were widely distributed in the oceans at that time, they fixed Co2 in the atmosphere in the lithosphere and released oxygen at the same time. The early atmosphere and the primordial ocean contained a large amount of reducing material, coupled with strong volcanic action, cyanobacterial photosynthesis produced free oxygen accumulated in the atmosphere, after nearly 1 billion years of long accumulation, about 2.2 billion years ago, the Earth's atmosphere finally contained a certain amount of free oxygen and formed the ozone layer, aerobic eukaryotic single-celled organisms evolved from prokaryotes and appeared in the oceans at that time.
Terrestrial plants evolved from certain algae living in the ocean about 450 million years ago, the most primitive types of vertebrates traced back to 530 million years ago, invertebrates traced back to 550 million years ago in the ancient ocean, macrophyllum algae traced back to living in the ancient ocean 2 billion years ago, and some prokaryotic life, such as bacteria and cyanobacteria, lived on Earth for more than 3.5 billion years.
The Precambrian period was divided into the Archaic and Proterozoic.
The Archean Dynasty is 4.6 billion to 2.5 billion years old,
The Proterozoic is 2.5 billion to 543 million years old.
The present universe is 543 million years old.
The oldest remains of life on Earth 3.85 billion years ago, found in the ancient rocks of Greenland. From the very beginning, small organic molecules appeared near hot springs on the seafloor, with enough heat and suitable chemicals to provide the necessary needs for the evolution of life. The earliest organisms were cyanobacteria, which evolved the characteristics of being able to perform photosynthesis.
In the early Proterozoic period, life on Earth was still confined to the ocean, and due to the continuous photosynthesis of algae and some bacteria, a large amount of oxygen was produced, and some eukaryotes with real nuclei began to appear, such as primitive sponges and jellyfish-like organisms.
Cambrian
490-443 million years ago, the explosion of species, in which the Earth suddenly emerged in more than 20 million years, a variety of animals suddenly emerged, and the same rapid origin immediately appeared. A series of arthropods, brachiopods, worms, sponges, chordates, etc., which are basically the same as modern animal forms, appeared on the earth, and they appeared collectively, forming a prosperous scene of the simultaneous existence of a variety of phyla. It belongs to more than ten animal phylums such as sponges, coelenters, gills, leafpods, brachiopods, molluscs, arthropods, echinoderms, chordates, etc., and some strange taxa with unknown taxonomic locations, as well as a variety of symbiotic seaweeds. For example, trilobites with carapace have appeared in various parts of the world, and the huge predator Odd Shrimp has evolved huge pliers that can easily break the carapace creatures of the time to become the overlord of the sea. In the Cambrian Period (543 million to 490 million years ago), a primitive jawless fish, the Haikou fish, appeared.
Ordovician
Between 490 million and 443 million years ago, all living things still existed only in the ocean. The trilobite family was particularly large, divided into separate trilobites, and the ocean overlord was fangjiaoshi, a huge soft-body predator that could reach 10 meters in length, similar to the current squid and nautilus. Known as the sea scorpion, the giant feathered horseshoe crab is good at ambushing, and the horn stone is their only natural enemy. The land is still barren, with primitive slime molds and moss growing along some rivers.
Shiruki
Life has developed steadily over the past 443 million to 417 million years, and corals, sponges and mosses have developed in the tropical Qianhai region. The winged horseshoe crab reached a certain number, replacing the horn stones that were severely damaged during the Ordovician mass extinction and becoming the hegemon of the sea. At the same time, the brundo scorpion, the largest in history, appeared, with gills that modern scorpions did not have, and had good eyesight to find food. Under the threat of arthropods, many fish have evolved protective armor and have more advanced organs.
In the late Silurian period, under the cover of some ferns and fungi, some polypods and other arthropods began to land for the first time, after which a large number of organisms expanded to the mainland.
Devonian
Between 417 million and 355 million years ago, the land and sea have achieved unprecedented development. During the Early Devonian period, land was still sparse and primitive. Due to the later flooding of forests, the first tree-shaped plants appeared in it, called the ancient sheep's tooth, which was widely distributed along the river and in the estuary area.
Terrestrial animals are still dominated by arthropods, such as spiders and polypods. Some fanfin fish first evolved lungs, were able to come ashore from the sea, and evolved slow movement of limbs, such as the heyn salamander, its close relatives, the stone salamander and the echinacean salamander, both of which appeared in the Late Devonian period and belonged to the primitive amphibians and labyrinths. Their limbs are actually powerless to move on land, and the salamander has eight toes on each limb and the salamander has seven.
Two terrifying species of bony jawfish appear in the ocean. The body of The Dunn's fish was more than 8 meters long and was distributed in North America, North Africa and Europe at that time. Its mouth consists of two sharp bony tooth plates that can be cut together like a sharp knife, and the jaw has a strong bite force that cannot be compared with other organisms; the lungfish is four meters long and distributed in North America. The body surface is covered with larger scales, with a strong jaw and sharp teeth, and sharks such as the pectoral ridge shark appear for the first time in the ocean.
Carboniferous
Between 355 million and 295 million years ago, the Carboniferous period was still in a greenhouse climate, and the low-lying areas were already occupied by dense forests and swamps, the main species were ferns, wood thieves, and huge and strange stone pine trees, some of which reached 50 meters.
The oxygen content in the atmosphere is extremely high, and many organisms inhabit these forests, such as the largest giant arthropod, the ancient centipede, called the ancient horse land. The huge giant veined dragonfly, with a wingspan of up to 75 cm, is the top predator.
The swamp area is conducive to the survival of amphibians, and the emergence of proto-water brown salamanders that are good at swimming is 2.5 meters long and belongs to the amphibian carboniferous lizard, in the species of amphibians and reptiles. The earliest reptile oil shale lizards evolved, small in size and similar in appearance to lizards, often laying eggs far from water sources. In the late Carboniferous period, a small psycnosaur reptile appeared, with a body length of 2 cm to 3.6 cm. Sharks and bony fish dominate the ocean world, and the Hitchhorn tooth fish is a top predator, with a body length of 8 meters and teeth that can grow to tens of centimeters, making it the most ferocious freshwater fish.
Life evolved from the ocean, from inorganic molecules to organic molecules, evolved to single-cell life, and then evolved countless marine organisms, evolved to terrestrial organisms, all subject to the external fluctuations of the earth's environmental climate, any large fluctuation in the earth's climate will make biological life mass extinction, the next article Five mass extinctions of earth's organisms, how organisms are extinct.