Timeline origin of life

Origin of life

A series of fortunate events.

Chemical evolution on early earth

Fist cells

First organic molecules

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First organic molecules

Protobionts

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Oparin envisioned that the organic molecules would, over vast spans of time, accumulate in the sallow seas to form a "sea of organic soup". he envisioned smaller organic molecules combining to form larger ones under such conditions. The miller and Urey experiment was for proving that the oprganic molecules can form in a reducing atmosphere similar to that thought to be present on early earth, and what they do is simulate the reducing atmosphere of early eart contained, water, methane, ammonia, and hydrogen.

Study of the origin of life is an active area of scientific research today, Astrophysicists and geologists estimate that earth is about 4.6 billion years old. The atmosphere of early Earth apparently included carbon dioxide, water vapor, carbon monoxide,etc.. It may also have contained some ammonia, hydrogen sulfide and methane. The early atmosphere probably contained little or no free oxygen.Four requirement must have existed for the chemical evolution of life: little or no free oxygen, a source of energy, the availability of chemical building blocks.

Protobionts are vesicle-like assemblages of abiotically produced organic polymers. These Protobionts exhibit ,many functional and structural attributes of living cels. They maintain an internal chemical environment that is different from the external environment, and some of them show the beginnings of metabolism

Two main models seek to explain how the organic precursors of life originated: the prebiotic soup hypothesis proposes that these molecules formed near Earth's surface, whereas the iron sulfur world hypothesis proposes that organic precurors formed at cracks in the ocean's floor.Organic molecules may have been produces at earths surface.

Several additional steps had to occur before a true living cell could evolve from macromolecular aggregations. For purposes of discussion, they use LUCA to refer to the hypothesizes last universal common ancestor.