Re: A critique of the BBC aquatic ape programme and the transcript.

Pauline M Ross wrote:
> On 23 May 2005 19:57:27 -0700, "JAE" <jae@xxxxxxxxxxx> wrote:
>
> >> [Algis] In evolutionary biology we generally assume that the
characteristics
> >of species are the result of natural selection.
> >
> > Evolution and natural selection are not
> >synonyms. One is but one mechanism of the former and it is BY NO
MEANS
> >sufficient to use the postulate that natural selection was
responsible
> >for an observed difference as the basis of the same conclusion.
This
> >may or may not be the case, but that's what remains to be
DEMONSTRATED.
>
> Taking these snips out of context, you are undoubtedly right. But in
> the context of a discussion about locomotion, what else could it be
> but natural selection? Random genetic drift? Hardly. Sexual
selection?
> I don't think so. What else but natural selection?

Consider this: Snow is a regular substrate that some animals have to
move through. What creature moves better through the snow, humans or
chimps? If it's humans, is it because we've had selection to move
through the snow? Really? Considering that the human form has
remained more or less unchanged from a form that evolved in a place
where the creatures originated it doesn't seem terribly reasonable that
anything about our mophology is related to any selection for moving
through the snow.

If you begin with the assumption that the trait was a direct result of
postive selection for the trait as expressed, you will reach no other
conclusion. You've also not demonstrated anything. You've merely
restated your premise. In context: The argument that Algis is making
is that selection is responsible for differencesis that we swim better
than chimps, therefore selection was responsible for this difference.

But there *are* other things that can happen. Is/are the trait(s) (and
yes, even a locomotive one) a secondary effect of selection elsewhere?
(e.g. is our "streamlined" body really streamlined for swimming or is
it a superficial side result of an elongated body for some other
purpose? Is our "hairlessness" really anything that resulting from
being in the water or is it the result of some other factor that may
[or may not] convey some advantage in the water; are gibbons largely
bipedal on the ground because it's advantageous for them or because
their erect posture for brachiating coupled with their rather
imbalanced intermembral index makes this the most viable option?) Is
the difference when compared to another taxon a result of drift? Think
here not about the difference being one *favoring* a taxon, but one
where a trait was lost in the other taxon. (e.g. Is our swimming
ability really much different than the basic mammalian condition and is
it perhaps the chimps who have experienced diminished abilities
because, when not needed a trait *can* disappear, though there is no
expectation that over any given period of time it must?)

It's rather poor science to select a few traits, claim analogy, yet not
explore the analogy to see if it holds on closer inspection. That's
exactly what I see Algis doing. He's said that the only important
comparison is to other apes, though in doing this, he's given up a
reference as to what is and what is not an actual adaptation and what
is merely a difference. To prevent ourselves from falling into Algis's
tautology, we have to ask real questions, many of which he's declared
off limits for reasons that seem clear only to him. Are we
particularly adept swimmers compared to the host of creatures who show
aquatic adaptations? Are there universal traits that aquatic creatures
have that we do not? Why? Are the similarities really analogs (e.g.
is our hairlessness comparable to the hairlessness of a dolphin despite
the fact that we retain copious amounts of hair over our bodies) or is
it merely a superficial similarity? Is the suite of traits consistent
with the level of necessity proposed? This too may be difficult to
actually address directly, but it's a damn shot better than simply
stating that it was an adaptation therefore it's an adaptation.

Beneath any assumption of adaptation must be some way in which the
adaptation was or is advantageous. Simply saying that if we swim
better, we'd be less likely to drown is again overly simplistic since
it provides no compelling reason why we'd swim. If it were so simple,
why isn't being an adept swimmer something than every taxa would have
achieved (and of course, why is it that humans, without training, are
so damn likely to drown)? Hell, even safer is to stay on dry land like
the bulk of primates do. What compelled a lineage to get in the water
(often enough to develop specific adaptations)? Simply saying that
(generic) 'wetlands' are 'food rich' isn't even close to sufficient to
establish premise. Wetlands are about as variable as any environment
and the presence of things that might be food is not the same as
actually turning the plants/animals/fungi into calories and nutrients.
The presence and the ability to extract are not always the same thing.
What sort of wetland are we talking about and is there evidence that we
inhabited AND utilized these particular wetland resources? What's the
NET return on foraging? If it's energetically expensive to swim and
dive after something, it's not terribly important how much total food
there is. These are far more important that saying "look, aquatic
stuff in the same deposits as a hominid" and, allthewhile ignoring the
possibility of taphonomic bias, concluding that these aquatic resources
were available to a wading/swimming/diving ape. These things can be
investigated and reasonable answers would make a wet ape plausible.
This is not some "higher bar" but it's the sort of stuff that goes on
in looking at how prehistoric humans have used or not used a number of
environments and it's the sort of stuff that needs to be looked at to
learn something more and make PROGRESS in a field (rather than just
whining about how "soandso didn't do that so why do I have to" thus
guaranteeing that the same mistakes get repeated.)

And no, it's not easy, but it's how you have to actually address the
issue.

.

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