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Spearthrower wrote:

I'm With Stupid wrote:I've been watching a Brian Cox documentary again. One that pointed to the idea of these hydrothermal vents being the origin of life. He also presents the (qualified) position that life is basically an inevitable consequence of the physics and chemistry of the universe under certain conditions. Basically given the right conditions, life will have no choice but to emerge.

So given that, and given the fact that hydrothermal vents are present in many areas of the world, why is all life related? Why have these vents not been churning out biologically unique specimens throughout the earth's history (even if there was a period in deep history where conditions were more receptive)? Or have they and only one strand survived? Perhaps it would be impossible, once our ancestors got a foot hold, for anything else to be allowed to evolve beyond that earliest stage whatever it might have been?

Any thoughts?

Obviously I know that hydrothermal vents aren't exactly a proven theory at this point.

To answer your questions:

Assuming the model is right, then all life is related because the first basic life-forms would have evolved there and then propagated out from there evolving to colonize new niches, but still maintaining their common ancestry.

These ecological and behavioral niches are also the answer for your other question. The first life forms would not have had to compete with other life forms. New life forms have no 'history' of competitive evolution, or of evading predators. A new life form evolving in an already complex niche needs to come out running, so the existence of life makes new life forms less likely to survive, those existing life forms having the benefit of an evolutionary history bestowing on them capabilities that make them outperform in every appreciable way a de novo life form.