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Re: Where are the zoologists?
Pat Dooley (patdooley@aol.com)
17 Dec 1994 00:10:29 -0500
In article <1994Dec16.104155.20144@henson.cc.wwu.edu>,
n8010095@henson.cc.wwu.edu (Phillip Bigelow) writes:
>>NOt everything needs or has an explanation. For
>>instance Dawkins uses the example of the vertebrate eye. The
photreceptor
>>cells are wired "backwards"; that is, the light-receiving part of the
cell
>>faces the back of the eye, and the nerves come out of the cell at the
end
>>the faces the _front_. All vertebrates are wired this way. Why? is it
>>because it was somehow advantageous? No, it is most likely there for
what
>>are known as "historical" reasons. It just happened that way, for no
good
>>reason, and since it was that way in our common ancestor, then all
>>vertebrates have that eye structure.
>>Lucie
Evolution can't invent new features out of thin air. if the most primitive
vertebrate ancestor got its eyes mis-wired then all vertebrates are
condemned to share the same fate. But look what has been built
on that base - the acute vision of birds of prey; color recognition;
near night vision...The subsequent develops are pure evolution.
> Exactly so. Steven Jay Gould of Harvard has written extensively on the
>"randomness" of the evolutionary history of life. His point is that
>evolution doesn't _always_ have to have a driving force, or a driving
>purpose. Sometimes, it just happens. Time usually sorts out the "good"
>experiments from the "bad" experiments.
> <pb>
And, in the case of human evolution, time had a good few million years
at its disposal.
Pat Dooley
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