Re: Evolution, "adaptation", and what's currently adaptive

Bryant (
7 Sep 1996 11:56:23 -0600

In article <>,
Len Piotrowski <> wrote:

Bryant wrote:
>>An extreme adaptationist would expect that only birds
>>living on voles and other UV-absorbant poop-producers would have the eye
>Appears from my experience with extreme adaptationists that many more purposes
>associated with the detection of UV light would do as well. This is an
>especially surprising conclusion given the fact that vole poop/urine was
>apparently only recently discovered to absorb UV light. What other
>environmental materials may have this same property?

You allude to a nice point that hasn't yet been mentioned, I think. Some
traits will be favored by multiple selection pressures. More
interestingly, some traits will be countered by some selection pressures
and favored by others.

The net fitness effects of the trait in such cases, averaged through deep
evolutionary time, predicts whether a trait should be expected to
disappear from a population or not.

[Nice, adaptationist conjecture by Lenny snipped for brevity.]

>>>|> Interesting mapping function here: where does this "evolutionary pathway"
>>>|> exist?
>>>In the history of living organisms.
>>Boy, this is ironic. But I recommend that Lenny and others who do not
>>understand how evolutionary pathways can be identified read SJ Gould's
>>essay on homology, entitled "Why History Matters." (American Scientist
>>published it as a part of the collected works in _Exploring Evolutionary
>Boy, this sure is ironic. I ask for a clarification and end up once again with
>a not so subtle request by Bryant to get myself educated.

Oh, man. Whatever, Lenny. You asked a simple question and I offered a
great place to find an answer. There was no intention to insult in
that. I thought it was ironic that I would recommend Gould's essay
because our disagreements began with my critiquing Dr. Gould.

>I guess it doesn't
>do any good to question you on your home turf, eh Bryant? But thanks anyway
>for the recommendation. I think I can handle the terminology from here on.

You have completely misconstrued where I was coming from. I apologize
for not qualifying the heck out of the recommended reading statement, as
I will do, unsarcastically, from now on. This is a really difficult
medium to communicate on; all the cues of sincerity (facial expression,
tone of voice) are missing, and it's too easy to misread one another.