bipedalism
Alex Duncan (aduncan@mail.utexas.edu)
9 Jun 1995 20:48:03 GMT
In article <ghanenbu.9.00FED6AB@inter.nl.net> Gerrit Hanenburg,
ghanenbu@inter.nl.net writes:
>Subject: Re: Bipedalism
>From: Gerrit Hanenburg, ghanenbu@inter.nl.net
>Date: Thu, 8 Jun 1995 22:29:09 GMT
>>
>Can it be that the anatomical characters which show that A.afarensis
>and H.habilis were adept arboreal(as some believe)are retained
>primitive characters with little functional and/or behavioural
>significance?
Simply because a character is primitive doesn't mean that it has no
functional significance. For example, lungs are a very primitive
character that we couldn't do without. Closer to home, the broad thorax
and mobile forelimbs that we inherited from an early hominoid ancestor
are clearly primitive (for hominids), but are nonetheless important for
an understanding of human positional behavior.
>Isn't the derived anatomical complex associated with bipedalism
>of more importance in finding out about the lifestyle of early
>hominids?
Both derived and primitive characters are important for understanding an
organism's adaptive niche. In the case of Australopithecus and Homo, the
fact that "primitive" characters that may have been adaptive for
arborealism persisted through at least 2 Myr suggests that they had some
functional importance. This is especially true, as some of them (e.g.,
apelike humerofemoral index) would have reduced the efficiency of
terrestrial bipedalism.
Alex Duncan
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