subject: The Evolution Of Life [print this page] The origin and evolution of life is closely related to the origin and evolution of the universe. The life constitute elements such as carbon, hydrogen, oxygen, nitrogen, phosphorus, sulfur and other elements are evolutions after the "big bang". The data showed that the former biological stage is not limited to the chemical evolution of the Earth, the products of the chemical evolution widely exists in space. On interstellar evolution, some biological single molecules, such as amino acids, purines, pyrimidines, etc. may be formed on the interstellar dust nebula or aggregation, and then generated in the planet's surface under certain conditions such as polypeptides, polynucleotides and other biological molecules. Most primitive biological systems ultimately shape the formation of transitional forms by a number of former biological evolution on Earth, and that the life of the original cell structure. At this point, the biological evolution started until numerous complex life forms on Earth today. About 3.8 billion years ago, Earth formed a stable continental blocks, and a variety of evidences proved that liquid hydrosphere is hot, and even boiling. The modern extreme thermophilic archaea and methanogens may be the closest to the Earth's oldest life forms, and the way of their metabolism may be chemical inorganic autotrophic. The microbes in western Australia in 3.5 billion years ago may be the earliest evidence of life on Earth.
The emergence of the original crust marks the Earth by astronomical planetary era into the era of geological development, and life began to form with the original cell structure. But there are no more lives in a very long, dating back to 540 million years ago until the Cambrian when large numbers of shelled metazoan appeared, so the geological era after the Cambrian is called Panoptimization universe. The Archean is the oldest geological history. This is the initial stage of the original appearance of life and biological evolution from the biosphere, there were only a small number of prokaryotes, they left minimal fossil records. From non-living nature, Archean is a crust thin, geothermal gradient steep, volcanic - magmatic activity strongly and frequent, the strata generally suffers deformation and metamorphism, the atmosphere and the hydrosphere lack of free oxygen forming a series of special sediment period ; it is a period of sialic shell forming and the growing and an important period of mineralization as well. The initial surface of Proterozoic has appeared a number of wider scope, greater thickness and relatively stable continental plates. The contents above is the summary of the origin of life.
