Re: Bipedalism and theorizing... was Re: Morgan and creationists
John Waters (jdwaters@dircon.co.uk)
26 Sep 1996 19:11:56 GMT
Paul Crowley <Paul@crowleyp.demon.co.uk> wrote in article
<843593383snz@crowleyp.demon.co.uk>...
> >
> > The marginal variant specie are typically generalistic
> > omnivores. The specialist mainstream specie tend to be
> > frugivores, or carnivores, or leaf eaters, or graziers.
>
> We're really talking about all species - fauna and flora. Are
> such rules well recognised? I've never heard of them.
Clearly
> if whole species are wiped out by drastic climatic change
(such as
> that at the K/T boundary) then new niches open up, enabling
rapid
> radiative adaptation. But does it apply to normal climate
change?
JW: These are big questions which I will attempt to answer
within the next few days.
>
>>On the desert side the
> > niche is occupied by the human specie.
>
> How can you say this? Of terrestrial animals H.s.s. must be
one
> of the most water-dependent. We sweat intensively. Our
faeces
> are 75% water. Our water-retention mechanisms are minimal to
non-
> existent.
JW: I can say this because it is true. You can look in any part
of the world and find the human in semi desert niches. Desert
tribes have adopted various behavioural strategems to reduce
perspiration losses. They tend to walk slowly. They tend to eat
only at night. (This reduces the possibility of metabolic
heating and related perspiration.) They have developed a high
degree of bushcraft to find underground supplies of water; and
tubers and bulbs containing water. Think of the Kalihari
Bushmen.
>
> We agree that additional helplessness for a primate infant
(and
> its mother) is disadvantageous. You say, however, it leads to
a
> better power/weight ratio. Your logic here is extremely
unclear.
JW: It would be, if I said it. In fact, I say the reverse. The
improved power to weight ratio leads to an increase in the
period of infantile helplessness.
>
> In any case, I'm sure that "a better power/weight ratio" is a
> chimera. How could, say, chimps or dogs or dolphins achieve
a
> better power/weight ratio? >
JW: I'll answer this when I deal with your general questions
concerning genetic adaption and selection.
It's good to see we can agree on some things.
John
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