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

Bryant (
26 Aug 1996 15:47:31 -0600

In article <>,
Len Piotrowski <> wrote:
>In article <4vlbqe$> (Bryant) writes:
>>Gould & Lewontin claim that too many evolutionists see every single trait
>>in an organism as an _adaptation_ (a result of evolution by natural
>>I say they're mistaken in this generalization, that only some traits are
>For instance, "sugar craving" and "jealousy?"

Yup, I'd bet these were shaped by selection rather than drift, because
they have fitness effects. In identifying adaptations, one looks for
design features that likely increased organismal fitness.

>Let's say that Bryant claims
>that these "traits" are " an _adaptation_ (a result of evolution by natural
>selection." How do you claim to be a non-adaptationist by this process?

I never claimed that I don't subscribe to the adaptationist program. I
claimed that Gould et al.'s characterization of the adaptationist program
is exaggerative and inaccurate.

>There is no confusion. You pick a behavior and concoct an adaptionist
>explanation for it. I'm just pointing out the obviousness of it. Somehow you
>think you're exempt from an adaptionist's critique _because_ of it.

Nope, you've just misconstrued the nature of the debate between Gould and

>>>>Some reasoning, however, should quickly suggest that glucose is an
>>>>important limiting resource for us big-brained creatures,
>>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.
>Whether big brain, small brain, or no brain, "sugar craving" may or may not
>have anything to do with "our brains' glucose metabolism."

Indeed. Parsimony and inference were used on my end. Big brains do, by
the way, consume more glucose. So do the brains of folks with higher IQs.

We also have special sugar receptors on our tongues, remember. That's an
interesting design feature for mere genetic drift to have placed upon our
tongues, eh?

>>What *is* your point? That jealousy didn't inspire fitness
>>effecting behaviors? That, too, would involve imagination. So what?
>So, that's an effective counter to your assertion. Why pursue it if you
>believe the contrary can also be true.

You, not I, rejected the use of imagination in evolutionary biology.

>>>>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.
>Well, the point was that your "definition" is not the one used by biologists
>around the world precisely for my enumerated reasons. I quibbled with your
>precision, in other words.

And I quibble with your inaccuracy, here. This definition is indeed the
one used by biologists around the world.

>>This is silly.
>About as silly as your hypothesis I would note. If there is no "sugar craving"
>gene your thesis is worthless.

For the reasons I stated in my previous post (and which you erased), this
is silly. Your assertion would render nearly *all* thinking about ultimate
causation (be it about hearts or brains or tongues) utterly moot.

>>We don't know the location of even one of the genes which
>>code for the development of the human brain, or heart.
>You'll have some trouble there, eh?
>>Are you saying
>>that there are no genes for these traits?
>The brain and heart are at least physical objects. "Sugar craving" and
>"jealousy" are somewhat problematical in this regard.

They, like behaviors, are outputs of physical phenotype (in the brain,
the tongue, etc.). Where's the problem?

>So, let me get this straight. Your ' "hypothetical" and unidentified'
>evolutionary traits (sugar craving and jealousy) are more believable as the
>result of adaptive selection for "brain development" because - they are
>' "hypothetical" and unidentified?!' Boggles!

Boggles indeed. You misread my sentence, somehow. You said that the
lack of molecular genetic data about a given trait renders speculation
about its evolutionary origins moot. I said that this reasoning leaves
hearts and brains in the same boat, because we don't know exactly which
genes code for these traits.