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Re: Extinction of Dinosaurs



>Organisms get better the more derived they get (on a smaller evolutionary 
>scale, I think this is still valid.  I don't think Archaeopteryx was a crappy 
>flier because it was advantageous to be a crappy flier.  I think it was a 
>crappy flier because it hadn't had time yet to evolve into a good 
>flier). 

This last sentence - I think inadvertently on your part - smacks of
directional evolution, which I suspect most evolutionary biologists would
regard as fallacious.  Archaeopteryx  was not a "crappy flier" because it
was on the way to becoming a better flier - there is no selective pressure I
can imagine that would favour an adaptation because it might turn into
something really nifty in a million years or so.  Archaeopteryx flew the way
it did (however that was) because doing so was adavantageous to it at the
time (as you also say), and gave it, perhaps, an advantage over other even
more inept fliers.  The fact that this proved to be a step in the direction
of more fully powered flight is serendipity.

>     Today, we tend to see evolutionary adaptation as a process of 
>contingency, not improvement.

Exactly.  The rest of your post doesn't bother me at all, but I had to jump
on the above.
--
Ronald I. Orenstein                           Phone: (905) 820-7886 (home)
International Wildlife Coalition              Fax/Modem: (905) 569-0116 (home)
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