|
|
Re: Death of a hypothesis
Elaine Morgan (elaine@desco.demon.co.uk)
Thu, 4 Jul 1996 12:18:01 GMT
In article <4psobj$142b@maze.dpo.uab.edu> karen@uab.edu wrote...
> 74467.2253@compuserve.com (David N. Barnett) wrote:
>
> >:karen@uab.edu (Karen Harper) wrote:
>
> >:>>Anybodt gor any ideas about why nothing else has a chin?
> >:>
> >:>This is just a thought on chins: I would rather respond to the
> >:>question of why do humans have chins....I think that it is because
> >:>evolutionary traits evolve by being adaptive, what evolves is
> >:>determined by whatever trait is already out there and can be selected
> >:>for. That is pretty much random chance. If it gets selected for and
> >:>becomes significant it is because it is adaptive to surviving in the
> >:>environment. It seems to me that maybe the human chin has enlarged
> >:>over time because of the change in prognathic construction....as the
> >:>cranium enlarged and the morphology of the entire cranial skeleton
> >:>changed, the chin had to also. It seems like it would have something
> >:>to do with chewing, muscle attachments, joint function, bite, etc.
>
>
> >:Is the chin really that much larger, or is it just that the lower jaw
> >:bone was left "exposed" as alveolar prognathism reduced? i.e. did the
> >:chin move out, or did the teeth just move in?
>
> >:--dnb
>
>
> Personally, I think a bit of both. Probably, as the teeth shrank in
> size as did roots, the mandible appeared to protrude more. Other
> animals have chins too.
Which ones, please? I can't think of any except the elephant
Elaine
|