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How did living things form?

Molten lava contains so many chemicals during volcanic eruption. They might have cooled down to form carbon, hydrogen and oxygen which are the building blocks of life.All of the nutrients that go into the oceans and end up getting incorporated into biology, at first they're locked up in rocks and then they are eroded from rocks, enter the oceans, and take part in a complex recycling that ensures that there's always carbon and nitrogen and phosphorous available for each new generation of organisms.
The Miller-Urey experiments in the late 40’s and early 50’s showed that organic molecules could be formed by inorganic processes under primitive earth conditions. By discharging electric sparks in a large flask containing boiling water, methane, hydrogen and ammonia, conditions presumed to be similar to those of the early earth, they produced amino acids and other organic molecules experimentally. Using variations of their technique, most of the major building blocks of life have been produced: amino acids, sugars, nucleic acid bases and lipids.

Another source of amino acids and other organic molecule is meteorites. The amino acid content of the Murchison meteorite, for example, is surprisingly similar to that formed in the Miller-Urey experiments.

Both by earth-formed and meteorite-delivered processes, the early ocean could have become the thin "organic soup" proposed independently many years earlier by Alexander Oparin and J. B. S. Haldane as the starting place for life. The first "organisms" presumably consumed these molecules both as building blocks and as sources of energy. Upon the exhaustion of these early molecules, other strategies had to be develop such as photosynthesis. The first forms of photosynthesis was probably non-oxygenic using inorganic molecules as a source of electrons to reduce carbon dioxide, however, when these sources were exhausted, oxygen generating photosynthesis was developed using water as the electron source. The generation of oxygen had a most dramatic effect on future evolution.


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