Re: New Ethiopian Find - Oldest Biped At 3.8-4 mya

From: Algis Kuliukas (algis_at_RiverApes.com)
Date: 03/22/05 

Date: 21 Mar 2005 16:05:21 -0800

Rick Wagler wrote:
> "Algis Kuliukas" <algis@RiverApes.com> wrote in message
> news:1111184675.514116.304280@g14g2000cwa.googlegroups.com...

> > Fine. I can see you have a point, Rick, but I do think that when
> > discussing the pros and cons of any given locomotion you must not
> > forget the substrate through which the animal is moving. There is a
> > great deal of difference between the energy required walking
bipedally
> > on hard, hoof-worn grassland and walking through difficult bush.
There
> > must be far less difference for a quadruped. This is more than an
> > assertion. I have performed some simple (but painful!) experiments
to
> > test it and it appears to be correct. If one thinks about it for a
> > moment, it is rather obvious. Human bipedal efficiency is due to
our
> > striding gait, which is ever more hindered the worse the substrate
> > gets. A quadruped is hindered too, but if it does not rely on an
> > inverted pendulum gait (and apes' certainly aren't), it is less
likely
> > to be affected by substrate imperfections.
>
> The basic argument is that at distance travel - walking
> and jogging - humans excel. This is a demonstrable fact.
> Putting humans in rough bush country or tangled underbrush
> compromises this. I fail to see what point you are trying
> to make.

But that *is* the point. Difficult substrates compromise the
efficiency. And, specifically, the assertion is that bipeds are more
compromised than quadrupeds. If that is true, can't you accept that the
substrate has a key bearing on whether energy efficiency was a driver
of early bipedalism?

> The virtue of the treadmill is not that it mimics
> - almost said 'apes'.. gotta watch that - natural conditions
> but that it provides a simple context in which to measure
> performance. If the test shows that human bipedal walking
> is more efficient (ie energy expended in normal inimpeded
> gait) then that point is established. That's all.

I understand that. Treadmills are very convenient for scientists.
Unfortunately they don't really mimic the real world.

> Tossing in obstacle
> courses to increase energy expenditure is supposed to
> elucidate what precisely? You state that this "proves" that
> humans can only walk in flat, vegetation-free substrates.
> Your subject - presumably yourself- prove precisely the opposite.
> That human bipedal locomotion is pefectly seviceable in
> whatever non-ideal circumstances you placed yourself
> So I don't know what your point is. Especially when you
> have no similar data for non-human subjects.

It shows that our form of locomotion is very sensitive to substrate.
It's an assertion that it is *more* sensitive than quadrupedal
locomotion but the assertion is based on logic and an understanding of
how we walk.
If a knuckle-walking chimp turns out to be *more* efficient than a
human biped at moving through thick tropical rain forest, don't you see
how this would have a rather significant bearing on the debate, if the
earliest bipeds lived in such places?

> Furthermore, a quadruped is
> > more stable on uneven surfaces or when stepping over low branches
or
> > fallen logs whereas these obstacles would require costly changes in
> > posture whilst moving bipedally.
>
> No doubt. Your point?

So, a chimp is likely to expend less energy whilst moving through thick
bush than a biped, see?

> > Finally, where the bush is very thick
> > with foliage, as would be the case in a tropical rain forest, then
> > clearly the frontal profile area of the body is going be another
factor
> > that will effect efficiency and probably actually favour the
quadruped.
> >
> Depends on the quadruped. Some very sizeable animals - including
> elephants - inhabit trf.

Yes but they don't move bipedally, do they? Species that move through
thick bush are more likely to have a small frontal profile. Bipedalism
greatly increases that profile and is therefore probably less adaptive
- from the specific point of view of energy efficiency - for moving
through thick bush than quadrupedalism.

> > I can see that I was clearly very foolish to get into such an
argument
> > with such a person. But I think I made a valid point and expected a
far
> > more generous response from a scientist on a public disussion group
> > such as this. There is something about self-righteous egostical
> > personalities that brings out the worst in me and I admit that I
have
> > become part of the problem there.
> >
> One has to have a certain detachment - not to say joie de vivre -
> to get the most out of usenet. I don't mind the rough and tumble
> and can at times find the smiley face rules of moderated groups
> a tad confining. But those rules also serve a purpose. I just don't
> concede those groups the moral high ground.:-)

That's true enough. And I certainly wouldn't keep coming back here if I
didn't judge that on balance the gain was worth the pain. What I object
to is the hostility I seem to attract from some simply because of
holding one microscopically different view from 'the norm'. It seems to
be out of all proportion.

> > The really stupid thing is that I largely agree with Jason about
the
> > energy efficiency argument.
>
> I'm not sure about this. All Jason said is that he is not prepared
> on present evidence to take a high dive off a steep cliff with it.
> He wants the point to be more fully established - or refuted
> as the case may be. You seemed to want to dismiss it outright

Hold on. I said I largely agree with him. So I agree with his caution
and I agree with his general feeling that energy efficiency was a
driver. I just don't agree that this is how it started and that it
would have happenned just anywhere.

> I only differ in thinking that wading was
> > the factor that started the process going in the first place.
Whereas
> > Jason apparently thinks there was no energy rubicon to cross for
the
> > earliest bipeds, I think that shallow water was the place where
this
> > rubicon was eliminated.
>
> The problem you seem to be loathe to confront is the
> inconvenient fact that, by your account, modern apes
> perform perfectly adequately with what they have re bipedal
> abilities. There is no starting point since there is no reason
> to think that the LCA discovered wading as a wholly
> new activity for hominoid apes. Nor is there any reason
> to suppose that hominoid apes - especially the ones with
> orthograde postures and below branch slow climbing
> arboreal behaviours were not as facultatively bipedal
> as modern chimps.

In water they do perform perfectly adequately but not on land. That's
why, don't you think, that on land they move bipedally only 2-3% of the
time.

> I also appear to differ from him in that I
> > think that such efficiencies could only have been selected for in
> > certain substrates whereas he seems to think it would be selected
for
> > anyway no matter what substrates they moved through. These are, on
the
> > whole, minor differences however, especially when one considers
that I
> > am currently simultaneously arguing with Marc Verhaegen about the
same
> > thing but over differnt aspects. We largely agree (I think) on the
> > earlier wading-climbing part but differ greatly in how that evolved
in
> > the humanlike form. He thinks diving was the key factor there, I
think
> > it was energy efficiency.
> >
> Is Marc up to his old tricks? Denying he has said things
> he has said a thousand times?

Sometimes it's like playing a game of twenty questions with a
temperamental eight year old. When I think I've finally worked out what
he's thinking, rather than say 'Yes, that's it - you're right', he'll
say 'no, you still don't get it' as if the fact that I'm still guessing
proves he's cleverer than I am. He might well be cleverer then I am,
but I must say I find discussing things with him infuriating. I get
almost exactly the same experience with Jason, though.

> > I am just sick of all the nasty harranging that goes on here. We're
all
> > interested in human evolution. We're all Darwinists. Everyone has
an
> > opinion and something to offer, so why does it always have to turn
into
> > a pissing contest, leaving everyone smelling of the stench of
urine?
> > Why is it that some people think that just because they hold
certain
> > mainstream views it makes them not just a better scientist but, it
> > seems, a better person too, allowing them to treat adversaries as
if
> > they were untermenschen, with impunity. No-one has a monopoly of
being
> > right even if you hold a position that is in the majority.
> >
> Certainly not. I was through the Internet Infidels thread that
> Mike posted. You received an enormous amount of good
> advice and useful pointers there. You have your issues
> with Jim Moore. Fine. But Peez and Deb ie ergaster have
> done you genuine service should you have wit enough to
> take advantage. I know nothing about Peez but Deb was
> a grad student - perhaps still is- of David Begun at Toronto.
> She knows her apes. Go back over your exchanges and
> listen to her. Your academic career is going to run into the
> same flack it has gotten here. The manners will be much better
> but the consequences more dire.

I could see that Peez and ergaster were knowledgeable. And I always
appreciate it when people are open minded, including your good self,
Rick.

As for 'my academic career'... I don't think so. I've seen enough to
make me wonder if I want to spend the rest of my life having heated
egotistical battles over miniscule differences of opinion on
interpretations of very flimsy evidence. My plan at the moment is to
continue to enjoy the immense privilege of doing a PhD on my favourite
subject at the best university in the in the most beautiful city in the
world and then write a book about it whilst teaching high school kids
some biology.

Algis Kuliukas

Relevant Pages

  • Re: New Ethiopian Find - Oldest Biped At 3.8-4 mya
    ... >> compromises this. ... > substrate has a key bearing on whether energy efficiency was a driver ... > of early bipedalism? ...
    (sci.anthropology.paleo)
  • Re: A critique of the BBC aquatic ape programme and the transcript.
    ... > It isn't the substrate ... The substrate I was thinking of wasn't water, ... See, once bipedalism got going, I'm with the ... At least there is evidence that apes are upright when they're in trees. ...
    (sci.anthropology.paleo)
  • Re: New Ethiopian Find - Oldest Biped At 3.8-4 mya
    ... >> forget the substrate through which the animal is moving. ... >> great deal of difference between the energy required walking ... efficiency drops dramatically on anything other than a treadmill. ... quadrupeds, we're rather efficient. ...
    (sci.anthropology.paleo)
  • Re: New Ethiopian Find - Oldest Biped At 3.8-4 mya
    ... >> flat firm substrates. ... substrate one walks through has a big effect on the energy efficiency ... Algis Kuliukas ...
    (sci.anthropology.paleo)
  • Re: Bipedal Orrorin?
    ... >> firma and that other substrate you're always going on about. ... doubt, never getting into water), causes for bipedalism should be ... looked for on land. ... More instances and contexts for bipedalism occur on ...
    (sci.anthropology.paleo)