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Re: Several questions on evolution, and mutation (rate)
Posted:
Aug 27, 1996 1:50 AM


In article <Pine.ULT.3.91.960825034630.14248E100000@freenet.vcu.edu>, David Beorn <dbeorn@freenet.vcu.edu> wrote:
> Well, I don't know that we can say with CERTAINTY that life evolved but > people certainly do SAY it. I've heard calculations that to just form > one protein (amino acid?? I think) by chance, one of the building > blocks of life is 10 to the 46th power  and that's not even life. So the > probability for life is significantly greater than that. And the time > involved is significantly greater than the longest estimates for the age > of the earth  so what conclusions should you draw from this??
What do you suppose the person who did those calculations meant by the term "by chance"? My guess is that he calculated the number of different possible amino acid chains of some particular length, and called the reciprical of that the probability that any one chain of that length would come into existence.
In that case, the calculation is wrong, wrong, wrong. In genetic algorithms, which are systems that evolve in ways crudely analogous to biological systems, it is not uncommon to find the one optimum solution out of 10 to the 50th possible solutions, while only actually looking at 10 to the 4th trial solutions. In other words, evolution uses stochastistic processes, but gets to where it's going very fast.
You really can't get a clear understanding of evolution, I think, without handson experience. One way to get handson experience is to download a genetic algorithm demo and play with it for a few months. Another is to carry out some of the lab procedures like those of Frances Arnold or Gerry Joyce, where just a few generations of mutation, selection and reproduction produce RNA or amino acid sequences with greatly improved properties.
Steve McGrew
 Steve McGrew  stevem@comtch.iea.com New Light Industries, Ltd.  www.iea.com/~nli 9713 W. Sunset Hwy  phone 5094568321 Spokane, WA 99204 USA  fax: 5094568351



