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



JAE wrote:
> Algis Kuliukas wrote:
> > JAE wrote:
> [snip]
>
> > In gallery forest habitats prone to flood-desiccation cycles bipedal
> > wading is going to have clear survival benefits in flood cycles, and
> > walking efficiently on drying river beds is going to have clear
> > survival benefits during dry phases. What's your problem with that?
>
> You are still not addressing the survival value. Why is the
> facultative biped at a disadvantage? My problem is that you've got no
> selection in a adaptationist argument. There's nothing in your
> argument that differentiates between the facultative biped standing up
> and the obligate biped that relates to water.

I don't recognise the distinction. They were *all* facultative bipeds
at the stage I'm assuming this was important. Facultative bipeds that
were evolving, step by step, towards obligate bipedalism. There were no
obligate bipeds to compete with, just other, slightly more or slightly
less, facultative bipeds.

What gave some of them advantages over others? It's multi-faceted.

During wet phases, when wading was more important:
Stability of footing and being longer legged (makes them less likely to
drown) - likely to favour traits like more flat footedness, longer
legged and more urpight curvature of lower spine.

During dry phases, when walking was more important:
Greater efficiency of movement on dry ground (more likely to find food
and water at less cost during harsh times) - like to favour long
leggedness, traits to optimise gait etc.

> >
> > I think you're being too pedantic here. When I suggest that it is in
> > sub-waist deep water that some (literally watered down) need for the
> > traits of a terrestrial biped may be selected for, I'm not suggesting
> > that they spent there lives in that twilight zone. It's just a fact
> > that as one wades through water there is a continuum of depths. As the
> > water level goes down there is a shift in locomotor requirements: Less
> > physical work has to be done to propel the body forward, but more work
> > has to be done keeping one's balance. It's this shift, that must have
> > happenned thousands of times in the lifetime of a gallery-forest
> > dwelling hominid, that honed in those traits that would act as the
> > perfect precursor to human bipedalism.
>
> What is the selective process here? What killed off the facultative
> bipeds? What made them have fewer babies?

In wet spells predation and drowning would have been a major factor
killing off early hominins, in dry spells predation, starvation and
thirst - and specifically an inability to find food and drink often
enough, efficiently enough, would have been a major killer. You know,
the usual.

> [snip]
>
> > I do think it is astonishing that for 150 years paleoanthropologists
> > have scratched their heads on bipedal origins when, staring them in the
> > face, they could have gone to any zoo with a moat and seen that apes
> > move bipedally most predictably even in the shallowest of water. It's
> > obviously a big part of the answer. I think the tax payer would have
> > expected a better return from their input. I think they'd be appauled
> > if they knew how such a simple, plausible idea had been dismissed on
> > the basis of so little scientific enquiry.
>
> You joining Pauli on this "tax payer" kick, huh? This scenario where
> the general public's democratic cries decide what is and isn't good
> science? In the U.S. the "tax payers" as a whole would vote to fund
> "research" into "intelligent design" and 7-day creationism. You're
> raising a red herring.

Ok, good point. But perhaps in Europe the public are a little more
critical. Who knows. Anyway, substitute 'science expenditure watchdog'
for tax payer and you get the same point. 150 years of research into
human evolution and very little real progress.

Algis Kuliukas

.

Relevant Pages

  • Re: A critique of the BBC aquatic ape programme and the transcript.
    ... > survival benefits during dry phases. ... >> seemingly unrealistic amount of moving in and out of the water. ... > perfect precursor to human bipedalism. ...
    (sci.anthropology.paleo)
  • Re: Bipedalism in different substrates
    ... phobia that you claim forced proto-hominins into a pattern of bipedal ... >that the fact that quadrupedal apes move bipedally in water, ... But you claim they weren't wading for hours at a time, ... >selection of traits that would aid terrestrial bipedalism. ...
    (sci.anthropology.paleo)
  • Re: Bipedal Orrorin?
    ... Yes - snip, Jason. ... >> shallowest depths there is still a greater tendancy for bipedalism ... It serves your argument, I suppose, to interpret my claim that apes ... are most predictably bipedal in water in the most extreme way possible ...
    (sci.anthropology.paleo)
  • Re: Bipedal Orrorin?
    ... Yes - snip, Jason. ... >> shallowest depths there is still a greater tendancy for bipedalism ... It serves your argument, I suppose, to interpret my claim that apes ... are most predictably bipedal in water in the most extreme way possible ...
    (sci.anthropology.paleo)
  • Re: Bipedal Orrorin?
    ... Yes - snip, Jason. ... >> shallowest depths there is still a greater tendancy for bipedalism ... It serves your argument, I suppose, to interpret my claim that apes ... are most predictably bipedal in water in the most extreme way possible ...
    (sci.anthropology.paleo)