How did it start?

God created the first prokaryote cell ex nihilo three and a half billion years ago. That cell then reproduced and evolution is the process that explains the diversity that arose after that.

No, that was a joke. In regards to your opening statement:

quote:

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If people believe in evolution then they must believe in how the first living creature was put on earth.

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This is obviously true. Everyone believe that the first living creature came from some where. But there is a common logical fallacy that if scientists cannot prove purely naturalistic abiogenesis then evolution must be false. This is a fallacy because there is ample evidence in favor of common descent of all species through natural selection, regardless of how life did originally arise. If a creationist wants to dispute the theory of evolution, critiquing abiogenesis is barking up the wrong tree; the creationist must deal with the actual evidence that supports evolution of life after it arose, however it did arise.Second, no one has the exact mechanism or pathway that life arose. But various aspects of it pose no conceptual problems. As in all science there are unanswered questions, but the major pieces are pretty much in place. It is mostly now a question of figuring out the various details of the proposed pathways, and deciding which pathway is the most plausible.Sadly, early organic chemistry probably didn't fossilize, so even when scientists do come up with a working, detailed scenario, there will be no way to tell if that scenario is indeed the one that life did take.

I should also add that an atheist, and many agnostics and theists, are not afraid to simply say, "I don't know". That seems to be an answer that some Christians don't like very much.