Re: Lucy = slow
- From: claudiusdenk@xxxxxxxxxxxxx
- Date: Fri, 28 Sep 2007 13:32:18 -0400 (EDT)
On Sep 25, 9:24 am, Gerrit Hanenburg <G.Hanenb...@xxxxxxxxxxxxxxxxxxx>
wrote:
Marc Verhaegen <m_verhae...@xxxxxxxxx> wrote:
http://www.timesonline.co.uk/tol/news/uk/science/article2434423.ece
Wait a minute, this article says that Lucy couldn't run because she
didn't have an achilles tendon. That's interesting. What would count
as evidence that A. afarensis didn't have an achilles tendon, as even
chimps have it? True, in chimps the tendon is much shorter than in
humans, but in both taxa the gastrocnemius muscle inserts through the
achilles tendon (= tendo calcaneus) on the posterior aspect
(tuberosity) of the calcaneus.
Hardly matters. The point is that the origins of bipedalism had
little or nothing to do with mobility. This comprises even more
evidence that disputes the popularistic hunter/gatherer notion and
that supports/confirms my competing hypothesis that early hominids
were relatively sedentary and employed communal attack strategies to
preserve seasonal scarce resources. Accordingly, the origins of
bipedalism have to do with collective rock throwing, stick wielding
behaviors directed against large herbivorous mammals to whom with
which early humans competed for the seasonally scarce resources.
So, the phylogenetic bracket
Phylogenetic brackets don't tell us much at all. Faunal assemblages
(and paleoclimatology) are much more useful for fleshing out the
ecological context in which early humans first emerged.
in this
case suggests that A. afarensis also had an achilles tendon. Any other
evidence? Sure, the A.L. 333-8 calcaneus is described as "The inferior
half of the tuberosity is roughened for the insertion of the tendo
calcaneus" and A.L. 333-37 as "The tuberosity is roughened on its
inferior half for insertion of the calcaneal tendon" (Latimer et al.
1982. Hominid Tarsal, Metatarsal, and Phalangeal Bones Recovered From
the Hadar Formation: 1974-1977 Collections. Am. J. Phys. Anth. 57:
701-719). So, Lucy did have an achilles tendon.
Now, running is a function of stride frequency and stride length.
That's why even bipedally displaying chimps and bipedal Basilisk
lizards can run, and pretty fast too if only for short distances.
So, in the light of the above information it's likely that Lucy was
able to run, but probably not efficiently and for short distances if
she lacked the elongation of the achilles tendon (in humans circa 65%
of the total gastrocnemius length).
And of course, this research is also a fine piece of evidence that
humans were made for running.
Uh, no. Horses, antelope, wildebeast, lions, hyena and ostrich fit
this description. Not humans. Not now not ever.
Why else would evolve an elongated
achilles tendon if not for storing elastic energy for locomotion?
Well, sure, but even so hominid running ability is hardly useful for
running down prey or fleeing predators. It's maybe more useful for
mobilizing troops.
Comparative evidence shows that this exactly the kind of mechanism
other mammals use to increase the efficiency of their run
(particularly well developed in ricochetal animals such as kangeroos).
.
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