Re: Is the AAH a legitimate hypothesis? Of course it is.

From: Algis Kuliukas (algis_at_RiverApes.com)
Date: 01/01/05 

Date: 31 Dec 2004 17:05:10 -0800

Jason Eshleman wrote:
> In article <1104480636.626415.104550@c13g2000cwb.googlegroups.com>,
> Algis Kuliukas <algis@RiverApes.com> wrote:
>
> [snip]
>
> >Is it simpler to explain the clear human-chimp differences in
abilities
> >at moving through water as being the result of natural selection
(like
> >all the other *BILLIONS* of species pair-substrate permutations) as
the
> >AAH argues, or is it better to invoke *other* explanations for this
one
> >permutation and not any other?

Thankyou for answering the question.

> As the adaptationist explanations I've seen for these differences are
not
> simple, not elegant and lack in their consistency with the evidence,
it
> does not at this point appear to me that it is simplier to
> ascribe them a priori to some direct product of selection in the
medium
> you not the difference.

You're entitled to your opinion but I think they really *are* simple,
elegant and consistaent.

> Invoking the hypothesis, which is not yet
> supported with evidence, and confirming the hypothesis are not the
same
> thing, but you seem far too ready to leap from the former to the
latter
> with disregard for the overall lack of strength of support and now
appear
> to justify this because of some perceived need to generate
adaptationist
> explanations that directly address the problem as you frame it.

Perhaps they're not the same thing but I put it to you that in every
other species pair substrate combination, out of billions, no one would
even be doubting the natural selection explanation. It would be taken
as a 'given'.

> I do not enter with a pan-adaptationist view of biology and actually
> regard it as a true handicap for those who employ it. Natural
selection
> is but one of the mechanisms of evolution. I do not think you have
proper
> appreciation for this.

I have a tendancy to be sceptical of non-adaptationist arguments, be
they Panglosian spandrels, ontogenic side-effects of Hox-genes or
whatever. As Dawkins might put it, 'they are not helpful'. At best they
provide mechanisms for increasing variation within population. But if
they generate a phenotype that is weak, natural selection is clearly
the force that will eliminate them. The fact humans swim better than
chimps really must be due to natural selection because the weakest
phenotypes in that medium are clearly exposed to heavy selection.

> Selection does occur and produces some wonderous
> results, but it's not responsible for all differences between
organisms,
> not by a long shot.

That's not quite what I am arguing. Of course differences may evolve
through non-adaptationist mechanisms if they are absolutely neutral in
terms of selection. I'm trying to think of an example but it's quite
difficult. Perhaps the size of person's ear lobe might be one. I don't
think there is an adaptationist reason for some people having longer
earlobes than others, and I'm sure there are many such minor examples.

My example, however, certainly is *not* neutral. To argue that a
differential in *swimming ability* in water between two species could
have arisen for non adaptationist reasons seems to be a special form of
special pleading.

If that was true you should be able to name me a pair of species and a
given substrate where one species moves through that medium better than
the other, where it is the result of something other than selection.
Can you do that? I suspect you can't.

> Because I appreciate this and don't feel the a priori
> need for adaptationist explanations in all regards, I tend to be
> conservative and require fairly solid evidence to back adaptationist
> explanations and certainly do not put weight behind adaptationist
> explanations when the adaptations as described as so incomplete and
> shoddy.

Do you? Do you tend to be conservative in all species pairs, or does
this scepticism only apply to humans, apes and water? Can you point to
a single other (non-hominoid) pair and substrate where you are also
sceptical?

> I dispute your claim, residing in your parenthetical remark (which,
> however relevant, are unnecessary) that the *BILLION* [emphasis
yours] of
> "species-substrate" pairs are all adequately or in practice actually
> explained by direct selection in that environment. These things
indicate
> to me that you do not have sufficient understanding of evolutionary
> biology as a discipline or the natural histories of many species to
make
> your claims. It further indicates to me that you are making up odds
off
> the top of your head to emphasize a point for which you do not
actually
> have supporting data.

Which part do you dispute? That there are billions of species pairs? Or
that there are some which have non-adaptationist explanations for
differentials in their abilities to move in the five main substrates on
the planet? It's a very basic point, Jason.

Ok, you have a point about the odds. The maths isn't difficult, it's
deciding which species and substartes to include. If we assume 1.5
million species of fauna, the number of permutations is ((1.5m^2)/2 -
1.5m) x 5. As a great many of those species cannot realistically be
compared in more than two substrates, we might multiply this huge
number by a compensating factor of, say, 0.4 to arrive at the number of
permutations being 2,249,997,000,000.

A great many species (e.g. fish) will only move through one substrate
and so, when comparing them in water, one would have to say that they
are the same. Of course, it would be possible for these to then look at
more subtle differences in aquatic substrates (levels of salinity,
temperature, depth etc) and make similar comparisons between them
there. Every time such a difference was found, I have no doubt, there
would be an adaptationist explanation for it. But for the sake of this
little exercise, we may assume that all fish species are alll equally
as 'good' at moving through water as each other, so they cannot
contribute to number of non-adaptationist explanations.

I'm suggesting that only human-ape-water differences in water are
generally explained by such non-adaptationist reasons. So, assuming 14
species of gibbon, two species of Pan but only one of Gorilla and Pongo
that leaves the number of non-adaptationist permutations at
140,624,812,500. That's 140 (American) billion. I therefore put it to
you again that the odds of a species pair difference in a given
substrate being the result of a non-adaptationist reason is more than
one-in-a-billion.

> [snip rest of post leading up to where Algis again claims I've got
some
> prejudice]

It's not prejudice, Jason. I think it's going to be really tough to
admit that you've been wrong on this for so long. I don't envy you.
No-one could blame you for being reluctant to do so and for delaying
that decision to the last minute. But I really think that the smartest
thing to do is to just admit your error and quickly move on. One of the
main reasons the implications of this painfully obvious observation
(humans swim better than chimps) has not been fully assimilated is,
clearly, due to the mass of peer pressure not to do so. At some point
soon, though, that consensus will collapse like a pack of cards and
everyone will rush to argue that, of course, they always held the view
that the AAH was just badly formulated. If only Hardy had made it clear
he was only talking about humans being more aquatic than chimps, we'd
have given him a prize. The question is this: Do you want to still be
arguing about the quality of 'Beta-Max' when everyone else has moved
onto DVD?

Algis Kuliukas

Relevant Pages

  • Re: Evolution is not a fact
    ... All made of what some term micro evolution. ... selection as an example of this sort of thing, and so far you haven't addressed it. ... exactly what you mean by "species selection". ... Natural selection is the process that prevents billions ...
    (talk.origins)
  • Re: Darwins morality
    ... > selection is genetically determinist and based on sacrificing one's self ... SOMETHING THAT NO OTHER SPECIES HAS EVER ASPIRED ... If natural selection followed the classical models ... to be expected in a successful gene is ruthless selfishness. ...
    (sci.bio.evolution)
  • Re: Seanpit, ID and complexity
    ... random mutation and I assume natural selection. ... I, in fact, did define evolution: ... Even Paley recognized variation within a species. ...
    (talk.origins)
  • Re: Using evolutions effects
    ... Artificial selection is ID. ... And FYI, I agree that Natural Selection happens, WITHIN species. ... us to decide between evolution or creation. ...
    (talk.origins)
  • Re: Joe Public
    ... perm any two species and any of the five major substrates ... > Of course it's natural selection. ... it means that water has acted as an agent of selection in ... compared to chimps, and other primates, is all the more remarkable. ...
    (sci.anthropology.paleo)