Re: Bipedalism in different substrates

From: Algis Kuliukas (algis_at_RiverApes.com)
Date: 08/03/04 

Date: 3 Aug 2004 04:14:11 -0700

jae@ucdavis.edu (Jason Eshleman) wrote in message news:<b7af43cb.0408010938.38fd85b5@posting.google.com>...
> Pauline M Ross <pmross@ross-software.co.uk> wrote in message news:<i0cpg0tath3efte2jtpr9h8ta9su7jb49a@4ax.com>...
>
> [snip]
>
> > >> That chimps can and do subsist on a terrestrial diet and some human
> > >> hunter-gatherer populations can do the same indicates that there's
> > >> ample ability to make a living in these environments. It's a viable
> > >> niche. That's the relevence. To establish a plausible wading model
> > >> that seeks to show that a proto-hominid got significantly more of its
> > >> food from a foodsource obtained through wading, one needs to show that
> > >> such a foodstuff exists and can be obtained with enough ease and
> > >> abundance to be a viable niche. It could be, but this isn't known.
> > >> Since we don't see any non-techological primate making its living in
> > >> this way it provides doubt that such a niche is really available.
> > >
> > >Yes we do. We see bonobos feeding off aquatic fauna in streams, we see
> > >w l gorillas living off aquatic vegetation in beis and we see orang
> > >utans living off fruits off very wet, swampy tropical rainforest.
> > >These foods are not a large part of their overall diets but it is
> > >completely plausible that in the past they could have made up a
> > >greater proportion.
>
> They are not making their living off of these resources.

Define 'making a living'. Chimps are generalists and so are we. That
means that not one specific resource would be expected to be the *one*
(the only one) in which they make their living. Pan/Gorilla diversity
is much greater than we thought. (See Boesch et al 2002)

Boesch, Christopher; Hohman, Gottfried; Marchant, Linda F (eds.),
(2002). Behavioural Diversity in Chimpanzees and Bonobos. Cambridge
(Cambridge)

> They're
> including them as a minority part of their diet. (Is fruit in a
> swampy forest now an "aquatic resource?" That's a ridiculous stretch
> if you want to justify that the creatures waded to "waist deep water"
> to be predictably bipedal.) Why in none of these three do they not
> utilize the "aquatic" resources to a greater degree? Why does it
> constitute a minority of the items foraged for? This is a real
> question, not incredulity.

No, it's just incredulity. You may not have noticed (because you've
filtered all my posts for the last n months) but I've been arguing
non-stop that our ancestors were not aquatic specialists but
generalists that moved through water *more* than our ape ancestors.
So, it doesn't really matter whether they're eating 'aquatic
resources' or not - just that they're *moving* through water more than
did the ancestors of the great apes. Get it?

> It's important if you want to say that
> some previous hominid waded more that you justify why they waded more.

It waded more because it lived in more aquatic (ie wetland) habitats -
or habitats which were comprised of greater wetland micro-habitats, or
that they spent a greater proportion of their evolutionary history in
such places. Easy.

> If it's to get food, what food? Since it's a minority of the diet of
> other "wetland" apes, why is it?

But they're *not* wetland apes, are they? I thought that was the very
point you were just making. They aren't wetland species but our
ancestors were *more* wetland dwelling. That's the point I'm making.

> Are these wetland resources actually
> abundant enough such that they could be used to a greater degree? Is
> the energetic return on these items sufficient for wider exploitation.
> None of this has been demonstrated. Any time you propose a diet shift,
> you've got to take this into consideration. It is not sufficient to be
> vague. That no ape living in these "wetlands" makes larger use of
> these resources is VERY important.

If they were living on an coastal or island mangrove on the Med/Tethys
coast in the Miocene I don't think such questions would be
appropriate, do you? If they were living in a gallery forest in E
Africa in the Pliocene surrounded by kms of open, dry and relatively
hostile savanna - again, it's just irrelevant. Living on greater than
usual wetland resources is the only survival strategy, right?
 
> [snip]

Yes, snip indeed.

What JE snipped (again) was...

1) The point that as knowledge of bonobo and w l gorrila wetland
foraging behaviour is so new (1998 onwards) how do we know it even is
a minority behaviour? Some appear to just assume that it is.

2) The point about the Med/Tethys Miocene habitats and E African
Pliocene gallery habitats. Just keep pretending, and they might go
away.

3) That when you compare bonobo and chimp anatomy, it's the bonobo
(not the chimp) with the greater intermebral index and more anteriorly
positioned iliac arches - attributes geared towards greater
bipedalism. It's the bonobo that lives in wetter habitats and is both
more exposed to wading and anecdotally more prone to do so. Oops!
Nothing to say on that.

4) [Snipped a reminder of a previous snip.] That if Hardy hadn't been
misrepresented/misunderstood why did Reynolds/Groves suggest that the
AAH would have been better received if only it had been arguing merely
that water had acted as an agency of selection in human evolution. -
Let's not go there, either, eh, Jason?

> > >My hypothesis is that wading through water (the most predictable
> > >factor on the planet that gets extant apes moving bipedally) was a
> > >significant part of the locomotor repertoire of the earliest
> > >proto-hominins. Why Jason thinks this is "piss poor" is beyond me.
> > >Could it be that it involves the dreaded 'a' factor and that if it
> > >proved correct he'd have a great big splodge of egg on his face? I
> > >think so. Jason doesn't tell us which model he favours, although he
> > >has practically said that he thinks all the models are flawed too.
> > >
> > >The evidence is building up quite nicely.
> > >
> > >a) Theoretically, the most predictable conditions for an ape to move
> > >bipedally with no need for support from its upper limbs at all and to
> > >continue to do so for as long as the conditions prevail is, obviously,
> > >in waist deep water.
>
> And for the nth time, the selective advantage betweenthe obligate
> biped and the facultative biped in "waist deep water" is...?

Ooooh - that's a hard one. The selective benefit is that regular
bipedal locomotion is likely to lead to better bipedal locomotion.
(I'm amazed that a professional anthropologist could have so much
trouble with this but.. the evidence is there for all to see.) Better
wading leads to better terrestrial bipedlaism because postural traits
(those of the the lower spine and some of those of the pelvis) are the
same for both and because bipedal movement on two legs in shallow
water (shallower than waist deep) is literally watered down bipedal
movement on land. Wading in water is not exactly the same as walking
on land but it's a bloody good start! But the key point is that in
water apes are more predictably fully bipedal (without any support of
forelimbs) than anywhere else on the planet.

What's the selective advantage between the obligate biped and the
facultative biped in *any other* model? Don't tell me - the fact that
all the other models are flawed doesn't avoid the wading model having
to be flaw*less*.

> [snip]

Yes... snipped my arguments b , c, and d (oops!)

b - the evidence from extant apes backs up a;
c - those paleohabitats again.
d - a'pith postcranial traits are consistent with the wading idea too.

> > >> Actually, Norm, it was Krueger et al. whose data indicated that it
> > >> wasn't the reduction but the state of hairlessness that was the issue.
> > >> They noted that people with less hair to begin with show exactly the
> > >> same improvement as the hairier individuals when shaving. This
> > >> indicates that it isn't the reduction, but the complete removal that
> > >> is the issue, else the change in performance among those who started
> > >> with more hair should have been greater. Sharp and Costill's data
> > >> doesn't address this at all.
> > >
> > >Neither Kruger et al or Sharp & Costil looked at intermediates, so we
> > >simply cannot say whether intermediate hair loss - that is body hair
> > >reduction at levels less than 100% - reduces drag in water.
>
> The observation that hairier humans experience the same (not greater)
> increase in performance when shaving that the less hairy individuals
> experience *DOES* address intermediates.

If they had measured body hair shaved - which they didn't - and
correlated individuals' (male or female) drag reduction against the
amount of body hair removed it would have addressed intermediates. All
we have is a gross comparison based on a (fair) assumption that male
body hair was greater than female and that (unfair) body size and
other factors were identical. It's funny how you're so willing to
extend the data to fit arguments you favour but are so keen to pull me
up for doing so when they;re against you.

> They did look at performance
> in hair reduction at less than 100% by having a heterogeneous sample
> of preshaved individuals. Is this too tough for you to understand or
> simply too annoying to deal with? If intermediates had an advantage,
> then the hairier individuals should show a greater level of
> performance.

Body size is clearly an important factor here. The only meaningful
data would have controlled for body size. You cannot therefore
correlate an *assumed* (but not quantified) greater hairiness in males
- irrespective of body size or any other factor - with the results for
females. I can see how you are desperate to do that, but I'd rather
wait until such an experiment was done properly.
 
> [snip]

Yes, yet another convenient snip - oops - my challenge to you:

If I did such an experiment and it showed that there was a significant
positive correlation between body hair reduction and drag reduction
would you swallow your words?

I want to know becuase I have lost faith in your scientific
objectivity. I want to see, in black and white, that if such an
experiment was done and the results showed a correlation, you'd admit
you were wrong. Or, as I suspect, would you just twist out of it with
another lame excuse?

I'm prepared to do so. If the data shows that there's no correlation
with intermediate hair reduction (from ape-like hairiness) and only
with full body shaving, I'll admit that this data cannot be used in
this pro-AAH argument. Ok?
 
> > >Very clever but can you list out the diet of any proto-hominin? Of
> > >course you can't but that doesn't stop you ridiculing my refusal to
> > >speculate on such details. Water-side habitats are food rich. Of
> > >course our hominin ancestors could have survived there.
>
> Diets of hominids can be investigated to provide considerably more
> information than asserting that "they could have caught crabs" and
> "wetlands are food rich." Diets of hominids *have* been investigated.

That's just waffle. Investigated, yes. But can you list out the diet
of an a'pith? No, of course you cannot. And yet you continue to demand
that I do so to justify the outrageous idea that they might have
stepped into the water a little more than apes do today. Double
standards, yet again.

> Certainty about them? No, but asserting "they could have caught
> crabs" and believing that you've showing anything more complex than
> your ability to find a few letters on your keyboard is an insult to
> people who have actually spent time researching, writing and
> publishing.

I have the greatest respect for the workers who have spent years in
the field documenting exactly what extant apes do eat. Of course it's
no insult to those people, it's an insult to people like you who have
foolishly staked their reputation on this idea being wrong, even
before they have really properly and objectively looked at the
evidence.

> Waterside habitats aren't the same as getting in and moving around in
> the water. What, for the 17 zillionth time, do you think it was that
> they got by wading? Do try not to be vague.
>
> "I'm vague because it doesnt' matter." -Algis.

Another Moorish snip. God, if Elaine Morgan had done that, he'd have
nabbed it and put it on his precious little web page collection of
antiAATer gems.

The rest of the paragraph went on to say that as hominins must have
lived in a mosaic of habitats over the past 7My since the last common
ancestor what was the point of being more precise than saying that
wetlands are amongst the most food rich ecosystems on the planet.

In Boesch et al, most of the book is documenting in beautiful clarity
how diverse the ecological habits are of Pan. This is in one species
whose LCA might have been 2-3My. Therefore hominins must have had at
least that much diversity, and as we are so very different from chimps
and gorillas probably a whole lot more besides.

But never mind the facts - Jason's got the authority.

Algis Kuliukas

Relevant Pages

  • Re: OT: my prediction
    ... it's unsustainable, in terms of water and power, ... point the cost of the lifestyle to which people are accustoming ... there'd be a lot more people living in Asspimple, ... strict accounting of other people's values. ...
    (rec.bicycles.racing)
  • Re: Question on supply chain plan for World Pop. of 9 Billion
    ... worth of resources to bring all the world up to European standards ... of living and 5 earths of resources to bring the world up to US ... species are already in danger. ...
    (talk.origins)
  • Re: What to do about Islam?
    ... Malthus was conceptually correct if not mathematically precise. ... and decreasing resources, not necessarily expose an actual dilemma. ... standard of living. ... George got straight A's in pursuit of a high standard of living, ...
    (rec.org.mensa)
  • Re: OT: my prediction
    ... it's unsustainable, in terms of water and power, ... point the cost of the lifestyle to which people are accustoming ... I would tell people who comtemplated living there: ... strict accounting of other people's values. ...
    (rec.bicycles.racing)
  • Re: NDC - Superdome to Astrodome?
    ... >>> The people who thought that living under 20 feet of water would be easier ... >>> They were told to leave as 20 feet of water would inundate the city. ... >I have tremendous compassion for those who wanted to leave, ...
    (rec.music.gdead)