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Re: Several questions on evolution, and mutation (rate)
Posted:
Aug 22, 1996 9:13 PM


Vincent R. Johns (vjohns@cliff.backbone.uoknor.edu) wrote: : Felix J. Thibault <fthibau@comp.uark.edu> wrote: : > : > Andrew Singer <asinger@flute.aix.calpoly.edu> writes: : > ... : > > "..the mathematician D.S. Ulam argued that it was highly : > >improbable that the eye could have evolved by the accumulation of small : > >mutations, because the number of mutations would have to be so large and : > >the time available was not nearly long enough for them to appear..." : > : > I have been wondering about this argument for a while,as well,so maybe : > someone can clear up something for me. It seems that since the argument is : > probability based we can interpret it as follows: : > Given a multitude of earths,with evolution occuring as it does here, : > it the probability of the human eye arising again on one of these earths : > in the 4.5 billion years(from my early 80's geology book) it took here is : > infinitesmial. : > This is how I interpret Stuart Kauffman's argument on E Coli, _The : > Origins of Order_,pp2122,that we should not look at the probability of a : > known evolutionary event recurring,but instead should look for the : > probability that some such event could occur. We wouldn't expect other : > intelligent life forms to speak any human language after all, we would : > just expect them to have some system which serves them as our languages : > serve us.
: The analogy I've seen to this is that of tossing a coin 10 times and : looking at the pattern of heads and tails that results (a common : experiment in elementary probability); for example, we might get : T H H H T H H T H H .
: Now we can ask what the probability is of that exact sequence (0.001) : and marvel in amazement that that is what happened. Of course, : every time we do this we'll get *some* result, it just won't be : exactly the same as what actually happened.
Those final considerations assume, of course, that the species involved is not sufficiently advanced to be in the business of autoevolution. Good old H. sapiens is pretty close to such technology already. That's probably a critical point in the history of any planet on which intelligence arises. Some would say we're already past the point, but haven't yet gotten to "planned" autoevolution.
Truett Smith Cupertino, CA



