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


JAE wrote:
> Algis Kuliukas wrote:
>
>
> [snip]
>
> > The question is this: Was Man's ancestors *more* aquatic than the
> > ancestors of the apes since the LCA of both? Let's just stick to that
> > for a moment. What's so vague about it? If it was "Were the ancestors
> > of the Apes *more* arboreal than the Man's ancestors since the LCA of
> > both?" would that be as problematic for you? Why? or Why not?
>
> In this question you reveal your limits and your contradictions. Dare
> I say you reveal your own double standard. We can look at present day
> chimps and see that they are more arboreal than humans, that
> by-and-large some degree of life in the trees is present in virtually
> all chimps. It's part of the present day niche of their species that
> isn't part of the niche of all humans. This doesn't parallel swimming
> as swimming isn't part of the niche of all humanity. It's one of the
> many environments we can and do exploit, but hardly is it necessary or
> characteristic of the species as a whole. In this regard, your analogy
> is rather limited.

It might not be part of the human niche but it is as easily
demonstrable that humans swim better than chimps as it is that chimps
climb better than humans.

> But even this really is besides the point. You are confusing the
> general: "are apes more arboreal" with the specific of particular
> traits that make them more arboreal. Sure. A chimp is more arboreal.
> That's a boring "hypothesis" though that is trivial when addressing
> functional anatomy and not at all helpful in this regard. It's
> problematic if you're interested in functional anatomy and so if you
> started with this question in hopes of addressing funtional anatomy
> from it, I'd say it's hardly a hypothesis of interest and not worth
> taking time with. It's as boringly useless as being "more aquatic."
> They were more arboreal. BFD. Does this mean that any difference
> between the two is a result of that? I suspect that in honesty, you
> have to say that it does not.

Humans are more terrestrial than chimps. Our bipedality - one clear
distinction between us - is a clear manifestation of greater
terrestriality so how can you be so dismissive of this factor's
importance in our evolution?

> Deep six the arboreal umbrella. Not
> worth wasting time on and proceed ot the actual features and ask
> particular questions about how they function. We *can* look at
> particular traits in chimps and see *if* they are related to an
> arboreal lifestyle (or remnants of one in the past) but we do so by
> looking at the trait, how it is used *and* what other creatures seem to
> have similar adaptations. For instance, chimps have curved finger
> bones. This appears to be part of an adaptation for life in the trees
> because it shows up in a number of arboreal primates and doesn't seem
> to exist in the same fashion in more terrestrial species. While
> nothing in science is ever dead-set certain, there's justification for
> a reasonable hypothesis that the trait is related to arboreality. [Of
> course, it was very likely also present in ancestor species of chimps,
> so its presence in chimps isn't necessarily an indication of selection
> *for* it in chimps, but rather retention of the trait.] But in a
> large enough sample size we can see that form and fuction appear
> related and this confirms (it does not prove but confirms) that the
> form has provided a selective advantage for the particular function at
> some point. Without this we wouldn't be able to say if the trait
> followed selection or not even if it appeared to help them out in the
> trees.
>
> And herein rests where your methodology breaks down. If you want to
> look at hairlessness as an aquatic trait and claim that the unique
> appearance in humans is the result of selection, you've got to find a
> way of establishing that it is an aquatic trait and not caused by
> something else.

Clearly it is an aquatic trait. Nakedness in mammalia is found more in
aquatic groups than any other. Just because there are no useful
analogues *of limited levels of aquaticism* of naked mammals does not
preclude aquatic factors from being a major part of the explanation. I
don't see why we have to show that this is not caused by somthing else.
No-one, AFAICS, is arguing for exclusivity here. If body hair reduction
reduces drag in water then it would appear to be a plausible part of
the explanation for it.

> This can't be done by measuring human variation and
> apes only because it doesn't distinguish between cause and effect of
> another cause.

Maybe not. But even if there was an analogue of converegence that was
wholly suitable (e.g. a naked, fat, bipedal, large brained water-side
dwelling ex-squirrel) it wouldn't prove the case. I just think that in
matters of evolution we can never be certain about very much. It just
seems totally bizarre to me that some of the more plausible ideas which
set out to explain the major differences between humans and chimps have
not really been considered properly.

> The answers from shaved humans relate to selection only
> after you've assumed that selection *on this trait* occured as you
> suppose it did. Unlike the particular arboreal trait above where we
> can see it functioning in other arboreal creatures, you've got nothing
> to establish that hairlessness is an aquatic adaptation in humans and
> don't seem to want to look at how hairlessness appears in other
> creatures or what sort of environments actually produce hairlessness on
> what sorts of creatures.

But we have those analogues: the aquatic animals. My point is that just
because we don't see such analalogues in mildly aquatic animals it does
not mean similar factors would not have worked in humans that were
mildly aquatic.

> And there ARE traits that seem to serve a purpose that didn't arise
> because of that purpose. The great mobility that we have in our
> shoulder is a prerequisite for the type of swimming we do as it is a
> prereq for throwing things, both behaviors that I've heard here as
> explanations for how we diverged from apes. But the basic makeup of
> this shoulder isn't a product of swimming or of throwing. It's a trait
> that we share by-and-large with other apes due to a brachiating common
> ancestor. The adaptation was for brachiating, though it also later
> allowed for other unrelated things. And seeing a similar structure in
> New World brachiators but no other creatures we can be reasonably
> certain that it was an adaptation for brachiation. This HAS been
> studied and it's been studied using the comparative method, we
> researched and written up (A. L. Jones. The Evolution of Brachiation in
> Atelines: A Phylogenetic Comparative Study. 2004. PhD dissertation. UC
> Davis.) and because of it, we know more about how the suite of traits
> relating to brachiation function. Comparative functional anatomy. Real
> stuff, not the AAX bastardization of it that's been presented here.

Fair point but if those exaptations were not harnessed for other uses
since their original use they would probably have diminished. Swimming
and throwing therefore probably continued the selection for the
anatomical traits that originally had ben selected for from climbing.

> But you eschew this methodology for some bizarre reason and replace it
> with your own wholly insufficient one. Your methodology provides no
> answers. It remains a circular argument that doesn't address cause,
> though your umbrella "hypothesis" wants to address cause. This is a
> disconnect and makes the umbrella useless the subhypotheses. If you
> don't get any answers other than the ones you started with, why the
> hell are you bothering with the question in the first place? If you
> want to study something, do try to study it in a way that when you're
> done, you'll know more about the question you initially asked that you
> did at the beginning. As you're outlining it, this will not be the
> case.

Ad hoc objection against the AAH, number 389: Now, it's circular: 'The
AAH cannot win because you are setting out to show it's right in the
first place.'

Algis Kuliukas

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