Re: Bipedalism in different substrates

From: Bob Keeter (rkeeter_at_earthlink.net)
Date: 07/21/04 

Date: Wed, 21 Jul 2004 02:58:26 GMT

"Pauline M Ross" <pmross@ross-software.co.uk> wrote in message
news:1vhqf091j8n8nfuc9siq3r0dlu9ghcuorb@4ax.com...
> On Tue, 20 Jul 2004 03:55:59 GMT, "Bob Keeter" <rkeeter@earthlink.net>
> wrote:
>
> >>[Pauline]Inevitably they are more
> >> likely to have to come down to ground level and (if there's water
> >> around) get their toes wet.
> >
> >And our close ape relatives are, along with us, probably the least
> >arboreal of all primates. . . . . So water on the ground would obviuosly
> >"effect" them more than a spider monkey, even if the ONLY effect
> >was to get their toes wet! 8-)
>
> Yes, sure. And it is interesting that the great apes are all
> classified as having less than the full complement of fur, and also
> have a similar distribution of eccrine glands, not to mention having a
> larger body than most primates and no tail. It is possible that the
> effects of water on the ground are more widespread than generally
> supposed.

BUT, is not the human hairless condition, sweat reflex, eccrine gland
distribution, and such all supposed to be what separates us from our
ape ancestors instead of what unifies us with the family tree? Isnt the
whole premise of the AAH that "we" were connected to the water, all
wading around and splashing, swimming like dolphins and enjoying the
slick drag of hairless apes? Which way is it? You are even starting to
confuse me!! 8-)

> >Well, we know that the chimps, bonobos and gorillas did not just spring
> >up out of the earth 5mya, so. . . . they must have had ancestors, and the
> >smart money says that their ancestors likely lived in something close to
the
> >current environments. These current environments are much wetter than
> >the typical hominid environment.
>
> Yes, they must have had ancestors, but those ancestors were never
> anywhere where they could get fossilised, apparently. Their current
> environment is certainly very wet, although it is year-round-rainfall
> wet rather than water-on-the-ground wet. Whether it is wetter than the
> 'typical hominid environment' (well-watered?) is debateable.

Well, when I think of forest chimps and gorillas I see a lot of "elephant
ear"
type plants, dew and fog depositing little puddles every morning, ground
always wet or at least damp, and LOTS of green stuff. When I think of
an open forest, I see plenty of big trees, some scrub and brush and plenty
of big open patches of grass. MOST chimps and gorillas seem to hang out
more in the former than the later. Until some other evidence appears I
would suggest that we are compelled to presume that their ancestors
did something similar (particularly since that was the "original"
environment
of both of our ancestral lines).

> >Now that you mention it. . . . I wonder why the fossils of many forest
> >dwellers are so rare in comparison to savanna dwellers? Could it
possibly
> >be that the more acidic soils of the forest just dissolve bone material
> >more than the mud of a savanna water hole? Could that possibly
contribute
> >to the accumulation of hominid fossils and the obvious rariety of
> >fossil chimps and gorillas?
>
> Well, no, because all the early hominids were found in pretty dense
> woodland which would (presumably) be acidic. Actually, savanna fossils
> are tricky too, because anything left out the open is mauled by
> scavengers and trampled to dust by the local heavyweights.

What is this "pretty dense" stuff? That is even more vague than Ross's
"open woodland", "treed savanna", and closed woodland cases. Are
ancient hominids found in rain forests where the tree limbs would have
interlaced, in areas where there were trees every 30-40 feet and little
grass, trees every 100-200 feet with dense clumps around springs
or. . . . . .???

What is "pretty dense"?

There are just as many scavangers in the forest, and just about any rodent
will chew up a bone if given a chance. The odds of being properly covered
for fossilization are quite long, and Id bet dollars to donuts that most
fossils
come about after the creature is covered by flood waters (no matter the
environment). At issue is the effects AFTER this highly unlikely event. In
acidic soil, the bone will dissolve. In basic soil, it will dissolve much
less
rapidly. AFAIK, forest soils tend to be on the acidic side.

http://www.agronomy.lsu.edu/pdf/HUDNALL3.pdf

> >
> >And the interpretations of reputable scientists in peer-reviewed journals
> >supporting, actually SUPPORTING, even the vaugest tenets of the AAH
> >are to be found in . . .er . . . in . . . 8-)
>
> You'd be surprised. Try this one:
>
> Muskiet/Fokkema/Schaafsma/Boersma/Crawford 2004 'Is Docosahexaenoic
> Acid (DHA) Essential? Lessons from DHA Status Regulation, Our Ancient
> Diet, Epidemiology and Randomized Controlled Trials' American Society
> for Nutritional Sciences J Nutr 134 183-186, 2004

It would seem that DHA is a consistent component in human breast milk
even in areas where the mother could not be eating much fish and such.
Could
it possibly be that the " body fat" accumulated by the mother during
pregnancy
and by the fetus in utero is a way to store up this vital nutrient for that
brain growth spurt that we have haggled over? Certainly might be more
beneficial for a species so tied up in developing all this excess neural
mass
dont you think? 8-)

http://nutrition.ucdavis.edu/briefs/2003-02/minb0303.htm

Look for "mothers milk" in
http://nootropics.com/docosahexaenoeic-acid/

Wonder how human mothers in very non aquatic environments (lets
say Outer Mongolia, managed to produce enough DHA . . . . . .

8-)

The BEST source is things like cod liver oil, ADEQUATE sources
are red meat and body fat (either consumed or metabolized).

> There's quite a growing body of evidence regarding our requirements
> for certain elements common in seafood. I agree there's not much in PA
> directly supporting AAH, but then no one is actively researching it.
> Recent research (eg Reed and others) has been more in line with AAH
> than earlier conventional thinking.

8-) So now you have your aquatic ape cliff diving for cod liver oil? 8-)

Wouldnt push that proposition too far, else folk will see you in Mario's
very strange world.

> >We are tolerant of the hard vacuum of space. . . . so long as the
technology
> >supports it. If you could somehow take away human technology, do you
> >imagine that we could even penetrate the temperate zones?
>
> And could we penetrate very dry areas without any technology either?
> All apes (including humans) are naturally creatures of wet (or
> wettish) tropical zones. The spread into temperate, cold and dry zones
> is very recent.

They are creatures of ANY tropical or subtropical zone that provides
enough water to drink!

> >ANd what degree of wading, and "less than otter" aquaticism, would
> >possibly lead to hairlessness on the upper body and arms? 8-)
>
> You're getting mixed up, Bob. Wading => bipedalism, swimming =>
> hairlessness, subcutaneous fat.

8-) Confused? Perhaps. but it got a bit of a committal. Without a
swimming
ape, and one that does it routinely, would it mean that hairlessness and sc
fat fall off of the table as "proofs"? Wading we got (in bonobos), but for
some
reason they are specifically cited to do it quadrupedally instead of
bipedally
and unless you want to propose a swimming ape (swimming much more
efficient-mindedly than seals, otters, beavers, etc, etc, etc ad naseum) the
hairlessness issue is on hard times. . . . . hmmmmm m m m m Remember
when I was talking about reducing the mathematical equation to an
impossibility
therefore disproving the equation? You could be sneaking up on one of those
"paradigm shift" moments I think!! 8-)

> >Can you agree that modern humans are land mammals and have been for
> >quite a few years? If so, why have we not "returned" to characteristics
> >driven by our terrestrial environment? If you say something to the
effect
> >that the "aquatic adaptations" turn out not to be disadvantages in
> >terrestrial
> >evironments, by the way, you essentially disavow any connection of these
> >traits to a water envionment (for "dont care" states, there would be
neither
> >a pro or a con selection process and simple random drift must be assumed
> >as the "cause".) 8-) If the traits have "other advantages" in a
> >terrestrial
> >millieu, then they dont even have the need for water to have been
selected!
>
> Well, there's a nice damned-if-you-do and damned-if-you-don't
> statement. I see now why discussion with you is such an uphill battle.
> Essentially you are saying that an aquatic explanation is out of court
> no matter what.

I did not say that, you did, but then that was my publically stated
objective, i.e.
to present arguements where your own intellectual honesty forces a single
inferrence! So, instead of being apologetic, let me grin just a little bit.
If it makes
you think for a while and the eventual answer is "AAH be damed" then. . . .
.

> But I think the key is in the 'quite a few years'. I agree modern
> humans are (essentially) land mammals, but how long have we been so? I
> would say we have only been unequivocally terrestrial since the advent
> of agriculture (say 10 kya); before that *most* populations lived
> close to large bodies of water *most* of the time.

Now that is another generality that Im thinking that we could toy with
for a while. What is "close"? You were talking a while back about
a daily drink being inadequate for hominds. (Id daresay that there
are some !Kung, Inuit, and Arabs that might disagree.) But the idea
is this. If you assume a nominal walking pace of 4 mph, and a three
hour trek away from the "water hole", followed by a three hour
trek back to the water hole, our little hominid would be able to get
a drink at 7AM, do his hunting, and get another drink at 1PM with
no technology whatsoever. Three hours afoot at 4mph is twelve miles.

Now if I were to take a topological map of Kenya, or Tanzania or
Ethiopia or modern Chad and drew a 12 mile "boundary contour"
around all of the open water sources in the country, how much of the
country would not be within one of those circles? Interesting question
in a way, dont you think?

> So that means that (for most populations) that any adaptation to
> terrestrial life is very recent and still ongoing. That's why we
> haven't yet lost our SC fat, for instance, which is generally
> counter-productive on land.

Except as a store for such things as DHA and calories in mothers and
babies!

> >> [Pauline] Both subcutaneous fat and furlessness are commonly found in
aquatic
> >> species, and are very rare in medium-sized terrestrial species.
> >> Where's the contradiction?
> >
> >SC fat because there is no need for insulation in tropical streams, if
> >anything
> >there is a need to dump body heat, as we discussed elsewhere. If the fat
> >is for bouyancy, it would only have an effect when that portion of the
body
> >is immersed, again running hard against the wading hypothesis.
>
> There are lots of reasons for SC fat (in aquatics), and I'm inclined
> to think that streamlining is as important as anything else, perhaps
> more important than insulation. But insulation is *always* beneficial
> in water, I would have thought, even in the tropics. On land, of
> course, fat is very much counter-productive in the tropics.

Two things. . . . .Streamlining is ONLY important in creatures that need to
move fast through the water. Second, imagine that you are sitting, up to
your
neck, in a swimming pool where the water is 80-85 degrees F. Do you feel
ANY compelling need for putting on a winter overcoat or wetsuit? Mother
Nature in her evolutionary fervor probably would not either! 8-)

> Buoyancy may or may not be useful, it depends whether the animal is a
> surface or bottom feeder. Again, waders are unlikely to evolve SC fat,
> that would need full immersion (ie swimming)

Ah. . . . YES! So, in your humble opinion its not all that reasonable to
imagine that SC fat would have evolved for any of the standard AAH
reasons, EVEN if there were a wading aquatic ape somewhere back there?

Poor Algis, I hope that he handles the "heracy" better than Marc did when
Algis found himself compelled to diverge from the dogma.

> >
> >Hairlessness, as a drag reducer, would ONLY be effective on those
> >parts of the body immersed in the water, and in an upright, wading
> >posture the presented area drag of the body will be many magnitudes
> >greater than the localized "skin effect" of a little hair.
> >
> >Your choice. . . . do they contradict the wading hypothesis? If wading
> >is "out", the only thing you have left is to hitch a ride on the
"swimming
> >like a fish" bandwagon, and I dont think that even you think much of
> >that fabrication! 8-) Whenever you get down to the "2+2=0" case
> >its time to look for other answers!
>
> Not quite out of answers yet, Bob :-) As I said above, I see wading as
> the driver for bipedalism, and swimming (or complete immersion of some
> sort) as the driver for SC fat and furlessness, but the proportions of
> each (and of arboreal or terrestrial locomotion) would have varied a
> great deal. So no contradiction.

YET! 8-))))

Regards
bk

Relevant Pages

  • Re: Is the AAH a legitimate hypothesis? Of course it is.
    ... > replenished water. ... The whole paper was actually called 'Fat an Figures.' ... A chimp is arboreal so one would expect it to have big, ... >> Try swimming with a flat outstretched hand and you'll see the ...
    (sci.anthropology.paleo)
  • Re: my dog goes haywire in car
    ... despite HJM's dire warnings that I *must* put my ... Listen up, you fat, ignorant, pasty-faced bimbo, I didn't say anything ... water temps were in the 50s, which they still *were* at the time. ... To get her a little swimming time *before* the long, ...
    (rec.pets.dogs.behavior)
  • Re: Cavalli-Sforza Doesnt Support AAT (Diet)
    ... > Big Macs and gorging are not the only causes of fat accumulation. ... this just shows swimming isn't as effective as land based exercises ... in appetite that accompanies heavy running and cycling training. ... Note the mention of cold water. ...
    (sci.anthropology.paleo)
  • Re: Tobias 1995
    ... swimming and standing in water as a double-standard argument. ... Swimming is a form of locomotion. ... Better than any ape ... quadrupedalissm on land to bipedalism in water. ...
    (sci.anthropology.paleo)
  • Re: Is the AAH a legitimate hypothesis? Of course it is.
    ... but when humans sweat in humid conditions... ... >> water sources only with large bodies of water. ... >> also show up at water holes because other animals need to drink too. ... Then baby fat has nothing to do with the water. ...
    (sci.anthropology.paleo)