If the earliest known life form was an organism living off of chemicals seeping from volcanoes in the seabed, how did it ever manage to leave the seabed and a chemical diet for the shallows and a photosynthetic diet?

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If the earliest known life form was an organism living off of chemicals seeping from volcanoes in the seabed, how did it ever manage to leave the seabed and a chemical diet for the shallows and a photosynthetic diet?

In: Biology

Every time a cell replicates itself, there’s a chance for a coding error to change part of the cell’s genetic code.

This may then change the structure of one of the cell’s proteins, which may be a fatal flaw or an interesting adjustment that makes the protein work differently. The process is random, but in fast-replicating single celled organisms these mutations can accumulate quickly.

There’s heavy competition between ancient cells around these thermal vents for the delicious noxious chemicals spewing from the Earth, and the cells that evolved the most efficient metabolisms to live there crowded everyone else out.

That leaves everyone else with just one option: keep spinning that genetic roulette wheel until you develop a protein that enables you to live further from the vent, or go extinct.

Vast swathes of them probably did go extinct in the end, unable to mutate quickly enough or correctly enough to take advantage of a new environment – but a few did not. These new environments have no competition, and so even the jankiest mutant of a cell can take hold there and start replicating itself.

Over time that cells descendants become better at living there until they too begin crowding out the losers and the process repeats. Eventually the entire Earth is colonized with a vast variety of specialized organisms.