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From: cb@hlwpc.UUCP (Carl Blesch)
Newsgroups: net.origins
Subject: Re: Polka Dots
Message-ID: <536@hlwpc.UUCP>
Date: Mon, 6-May-85 13:50:28 EDT
Article-I.D.: hlwpc.536
Posted: Mon May  6 13:50:28 1985
Date-Received: Wed, 8-May-85 01:34:06 EDT
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> > They have also observed significant
> > adaptive change in some species as a result of industrial polution in
> > Britain, that is some animals have adapted to polution!! And
> > scientists were there to watch.
> 
> I assume you refer to _Biston betularia_ and other species of moths.
> So what kind of evolution is this?  Now they are changing back as the
> pollution comes under control.  This is an unconvincing example because
> it does not demonstrate anything but a horizontal change within a gene
> pool.  Only a shift of allelic frequency within a population.  Nothing
> new, which is what evolution requires.  Or does it require that?  I
> guess not.  Not a priori.  But post hoc it is seen to be a necessary
> part of a theory that's supposed to explain *what happened*.  This
> example doesn't touch it.
> 
I agree -- this is not proof of or conclusive evidence for evolution.
But my high school biology text never presented it as a proof or
a piece of evidence.  It was simply an illustrative case
of adaption that happened within a person's lifetime in response
to environmental situations.  As such, the example was used only to
illustrate a concept (evolution) which, because of it's long time and
subtle action, cannot be easily pictured, grasped, understood, etc.

Carl Blesch