|
|
Re: Evolution, "adaptation", and what's currently adaptive
Bryant (mycol1@unm.edu)
23 Aug 1996 16:37:02 -0600
In article <lpiotrow.373.321DF3AA@magnus.acs.ohio-state.edu>,
Len Piotrowski <lpiotrow@magnus.acs.ohio-state.edu> wrote:
>In article <4vkf6s$3d1i@argo.unm.edu> mycol1@unm.edu (Bryant) writes:
>
>>As should be obvious, explicit demonstrations of
>>the fitness effects of a given trait to our ancestors is quite impossible.
>
>By this stratagem, you've self-qualified for Gould & Lewontin's criticism
>while claiming the contrary (!?!).
Back up. You're confusing me.
Gould & Lewontin claim that too many evolutionists see every single trait
in an organism as an _adaptation_ (a result of evolution by natural
selection).
I say they're mistaken in this generalization, that only some traits are
adaptations.
What of what I said in the quote above confuses this issue?
>>Some reasoning, however, should quickly suggest that glucose is an
>>important limiting resource for us big-brained creatures,
>
>Hardly.
This isn't a very productive critique. What about our brains' glucose
metabolism suggests to you that dietary sugars weren't important during
our evolution. During childhood (not to mention the last trimester
of prenatal development), a *large* proportion of our metabolic expense
is accounted for by the demands of the growing brain.
>>and that jealous
>>behavior likely had fitness effects in our ancestors' lives.
>
>Only imaginatively.
If by this you mean we must extrapolate and imagine, of course that's
true. What *is* your point? That jealousy didn't inspire fitness
effecting behaviors? That, too, would involve imagination. So what?
>>By the way, for lurkers & others: "fitness" in evolutionary discussions
>>means "reproductive success," or ~how many copies of ones genes get passed
>>along to subsequent generations.
>
>The number of "copies of ones genes [that] get passed along to subsequent
>generations" is not an adequate definition of what "fitness" means because of
>the ambiguity in the meaning of "genes,"
Whatever. It's the definition used by biologists around the world.
>the process of 'passing along,' and what is meant by "subsequent generations."
You've got to be kidding. Reproduction and "subsequent" are foreign
concepts to you?!
>However, since no known individuals have ever, nor currently do, possess such
>hypothetical "genes," they cannot simply be inferred to exist from "Some
>reasoning," and thus become objects of evolutionary selection for adaptive
>reasons in the past, merely to satisfy a functional explanation for their
>purported occurrence in present populations, except by unsupported assertion of
>course.
This is silly. We don't know the location of even one of the genes which
code for the development of the human brain, or heart. Are you saying
that there are no genes for these traits? Parsimony deserves some
consideration, here, Lenny. What's the more fantastic assumption--mine,
that there are brain development genes, or yours, that there are not
because they're "hypothetical" and unidentified?!
Bryant
>Cheers,
>
>--Lenny__
>
|