Re: An alternative to ST and AAT
John Waters (jdwaters@dircon.co.uk)
10 Nov 1996 15:11:37 GMT
Rohinton Collins <rohinton@collins.prestel.co.uk> wrote in
article <01bbcdb9$208a50c0$424698c2@dan-pc>...
> John Waters <jdwaters@dircon.co.uk> wrote in article
> <01bbcd2f$8f445e00$3a2270c2@default>...
>(Snip)
> > JW: For what it's worth, the HBT explains that the
hominid
> > delay in switching to a highly efficient form of
bipedalism
>
> Again, see above.
JW: I was assuming that Paul was referring to early
Australopithicenes, which had a morphology similar to that
of Chimpanzees. This morphology enables bipedalism, but is
not as efficient for long distance walking. In this sense,
the australopithicene bipedalism was less efficient than
modern Hss.
> > In very hot conditions, the baby would die of
heatstroke if
> > carried continuously by its mother.
>
> You were there? What makes you think that a baby would be
carried
> continuously by its mother? Or even carried by its
mother? Even if it was,
> what is to say that it would not be shielded from the
heat of the sun by
> the mother, and therefore LESS likely to 'die of
heatstroke'? Your
> reasoning, John, has far too many holes in it.
Australopithecine babies
> were likely no less capricious than chimpanzee babies, as
the level of
> encephalisation was not dramatic in these species. If you
do not know why
> human babies are born helpless and therefore cannot gauge
when this
> condition may have emerged in hominid evolution, please
say and I will
> explain.
JW: Please do.
> > created an evolutionary demand for
> > less infantile body hair, increased number of sweat
glands,
> > the moulting of the foetal hair etc., to combat
infantile
> > overheating.
>
> Fallacious, since I have refuted your 'overheating baby'
theory.
JW: Refuted Roh, is not the same as disproved. Your own
clothing theory relies on the fact that the body
temperature increases when covered with an insulating
material. When a baby is carried in its mother's arms, the
mother's body and arms act as insulators. If the mother is
producing heat, as she would be if climbing an incline for
example, her body will act as a radiator as well as an
insulator.
>
> > The maternal adaptations were an increase in
subcutanous
> > fat levels in the chest/breast region, and on the
hips.
> > These are the places where the infant comes into
contact
> > with the mother.
>
> How did you arrive at this conclusion?
JW: By observation of HG tribes. This is how babies are
carried in the absence of prams etc.
>
> > The fat prevented the mother's own
> > internal body heat from being conducted into the
infant.
>
> This really has no logic whatsoever.
JW: Read the laws of conduction. Fat acts as an insulator.
A baby when carried in its mother's arms is relatively
static. The mother, by contrast, is using her muscles to
walk. If she is climbing an incline, this will require a
greater amount of effort, which means her muscles have to
work harder. When muscles are working they produce heat.
This heat is dissipated by conduction to the skin.
The heart is a muscle. This beats more rapidly at times of
great physical exertion. The heart produces heat as a
result of this extra activity. This heat is dissipated
through the chest wall, as well as via the bloodstream to
the rest of the body. This adds to the problems of an
overheating baby.
Of course, the primary reason for infantile overheating may
have been disease. A viral infection could lead to a fever.
But whereas a chimpanzee baby would survive because it
could dissipate this extra heat, an early australopithicene
baby carried in its mother's arms could not. Infantile
diseases of this kind are quite common.
John.
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