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Re: Speciation - how do you know?
Robert Gotschall (hobgot@ix.netcom.com(Robert)
19 Oct 1996 15:54:21 GMT
In <845721083snz@crowleyp.demon.co.uk> Paul@crowleyp.demon.co.uk (Paul
Crowley) writes:
>
>In article <54901i$me2@news.utrecht.NL.net>
> ghanenbu@inter.nl.net "Gerrit Hanenburg" writes:
>
>> Paul@crowleyp.demon.co.uk (Paul Crowley) wrote:
>>
>> >All hominids (including H.s.s.) have thick enamel. It is absurd
>> >to say that H.s.s. enamel is a primitive retention from an LCA
>> >7 mya - which is implied by your argument. Enamel (and dentition
>> >generally) is expensive and will evolve rapidly in new
circumstances.
>>
>So early, mid and late hominids had an abrasive diet. An abrasive
>diet of what?
>
>> Crushing shellfish is only one of them. (and unlikely in the case
>of primates)
>
>Since late hominids had a diet of shellfish ("coincidentally"
>abrasive) and were, in fact, primates, the "unlikeliness" goes
>out the window.
>
>> Why do Orangutans have thick enamel?
>
>Who knows? Has anyone done a "Jane Goodall" on Orangs? They'd
>need a head for heights.
>
>Paul.
Paul
Off hand I'd think there would be a close relationship between
skeletal and dental tissue. People living in a weightless condition
loose bone material very quickly. As I understand it, the calcium is
simply too valuable physiologically, to leave unused in bone. Is this
what you mean by expensive? Also, I think I posted earlier, given an
omnivorous diet and primate ingenuity, early homonids would very likely
utilize the littoral for food gathering. However, I don't get the
point about thick enamel. Are you suggesting that they were breaking
open clam shells with their teeth? Even relatively less sophisticated
feeders, such as sea otters, know enough to use
a rock for that. Frankly, I see little selective advantage for heavy
crushing teeth in a seafood diet. Massive dentition is more often
associated with a fibrous vegetable diet. However, have you considered
teeth used as tools, such as modern Inuit?
Hob
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