Re: [asa] three origin of life scenarios

From: gordon brown <Gordon.Brown@Colorado.EDU>
Date: Sun Jun 07 2009 - 23:37:41 EDT

This is not a response to any particular posting, but it is related to the
origin-of-life question. This is far from my field, and so I welcome
experts' corrections of my misunderstandings.

The search for extraterrestrial life involves looking for earthlike
planets. Apparently it is assumed that with similar chemistry and size and
orbital characterisitics about its star and maybe a few other properties,
life would have evolved there. Even though we can't yet show how that
first one-celled organism arose on earth, it is assumed that since it
happened and happened early in earth's history, it must have been easy.

Now, as I understand it, evolutionary theory involves common descent of
all life from that first organism. Correct me if I am wrong about that.
Does the existence of one organism that arose in this way prevent other
organisms arising independently in a similar way, rather than all having
to be descendants of the original one? If not, then if it happened only
once, that would make it seem that the origin of life is very hard and not
so easy as the searchers for extraterrestrial life hope.

Gordon Brown (ASA member)

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Received on Sun Jun 7 23:38:22 2009

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