jrg13 at psu.edu
Thu Sep 10 11:50:07 EDT 1998
James Adams wrote:
>There are good examples of intermediate forms in both the fossil
>history of insects and birds, and these have been extensively
>discussed in a number of papers. The discussion is too long to cover
>fully here, but the gist, as many of you know, is this. The original
>"non-functional" or "half-functional" wings probably had a perfectly
>good use, such as thermoregulation, gliding, etc.
Maybe, maybe not. Whether they were functional in some way may have
had nothing to do with their origin.
A few mutational
>steps could have modified the wings into something functional.
If they were not functional in the first place, their subsequent functionality
would, therefore, have nothing to do with their origin, and cannot, therefore,
be used to "explain" them.
>not take this to mean that I am suggesting that the process was in
>any way directed or simple.
If not directed, then without purpose.
Just remember that any structure that is
>in the slightest adaptive, giving even a small selective advantage
>would persist, and be able to be modified by the creative force that
>does exist -- mutation.
True, but the question that remains is how much this kind of process
is central or the only way of looking at the origin and development
(continued evolution) of novelty. As far as I can discern, historical
explanations of this kind are more rhetoric than reality (of couse
I recognize that as simply my personal (and maybe misguided) opinion.
Sincerely, John Grehan
More information about the Leps-l