Re: Bipedalism and theorizing... was Re: Morgan and creationists
John Waters (jdwaters@dircon.co.uk)
26 Sep 1996 19:12:19 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. I will attempt to answer them
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 of
the world's semi desert environments and you will find them
occupied by members of the human specie. Desert tribes have
evolved various behavioural strategems to reduce perspiration
losses. For example, they walk slowly. They tend to eat at
night. (This reduces the possibility of metabolic heating which
could lead to perpiration losses.) In addition, they have
developed a high degree of bushcraft, which enables them to find
underground water sources. They can also locate underground
bulbs and tubers which have water storage properties. 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. It
was the improved power to weight ratio which led to the increase
in the period of helplessness of hominid infants.
>
> 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 will answer this question when I deal with your basic
questions on genetic adaption and selection.
It is good to see that we can agree on some things.
John.
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