Several questions on evolution, and mutation (rate)

higgins at ebi.ac.uk higgins at ebi.ac.uk
Tue Aug 20 06:25:52 EST 1996


In article <4v6irj$ctt at picayune.uark.edu>, fthibau at comp.uark.edu (Felix J. Thibault) writes:
> Andrew Singer <asinger at flute.aix.calpoly.edu> writes:
> 
>>Greetings all,
> 
>>I have a great deal of curiosity about the varying viewpoints on 
>>evolution (having been an Anthropology major).  I just pick up the book 
>>"Darwin on Trial" by Phillip Johnson who's from my alma mater UCB.  Not 
>>that it's important, but I went into reading the book with considerable 
>>confidence regarding the validity of the theory of evolution.  However, 
>>the book has rased some interesting questions which I hadn't considered 
>>before.
> 
>>Let me take a quick excerpt from the book from which I have a few 
>>questions to throw out:
>>	"..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..."
> 
>>Andrew Singer
>>asinger at oboe.aix.calpoly.edu
> 
> 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.

For what it is worth; focussing eyes like ours (as distinct from simple light
receptors or compound eyes) cropped up at least three times in the evolution of
'animals'.   Once in vertebrates (me and my relatives), once in cephalopd 
molluscs (squids and octuputhingies) and once in salticid spiders (jumping 
spiders).  These three events are almost certainly independant and give rise to
three different ways of solving the problem.   The mollusc eyes focus by 
moving the lense, I believe, whereas mine focus by changing its shape. 

(this thread was crossposted to about a dozen newsgroups which might leave
bionet.molbio.evolution vulnerable to an interminable creationist/
evolutionist thread.  I just posted this here.)

Des "trying to focus on my screen" Higgins 


>       This is how I interpret Stuart Kauffman's argument on E Coli, _The
> Origins of Order_,pp21-22,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.
> My two cents-
> Felix



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