Re: Ectothermy?

["Larry Febo" <larryf@capital.net>]

Larry Febo wrote:
<< Just read Tom Hopp`s mention of "one time" evolution of dermal scutes,
follicles etc., I myself have a strong feeling about a once only development
of warm-bloodedness, and that being mainly for the incubation of the young
in a colder enviorn. In fact, I`m looking at endothermy before the synapsid-
diapsid split. (I don`t believe we should place diapsid beginnings way
after synapsid development based upon the scant fossil record of early
diapsid
forms).>>
And wasn't it in that same post, or a closely related one, that I placed
my bet for a one-time evolution of endothermy during the Devonian period?
Did
you miss that one? Isn't there a shark that has a core body temperature
above
ambient? Great White maybe? And what do you think of my "fuzzy little
salamanders" idea?
I'm still big on that. They would be your first land-brooding endotherm
candidate. Know of a good Carboniferous outcrop in the Seattle area? -- I'll
go dig some up.
Seriously though, lets keep an eye on the molecular systematists. As
Mickey Rowe pointed out, an analysis of "uncoupling protein" genes will
probably give a good time-estimate for the origin of heat generating
metabolism.
Tom Hopp
------------------------------
Yeah, Tom, I see what you mean. And what about the "hot blooded" tuna? A lot
of research there. That`s why I tried to "qualify" my statement of one time
development of endothermy to mean the giant leap to a brooding condition of
whats classically known as "warm-bloodedness". Here I`m thinking bottleneck.
Only one species making the transition to brooding behavior, and passing on
the genes to all subsequent types. Probably talking anapsid to synapsid.
With the subsequent benefits of ,(a tenfold? As stated by Chris
Lavers),increase in metabolism, I don`t see how the diapsid line could have
developed a similar condition, directly from the anapsids, in the face of a
competing population of already warm-blooded synapsids. As an offshoot of
the latter, yes. But as a completely independent development?,I don`t think
so. (at any rate, this I will further research to the best of my abilities,
and try to prove, or at least make a good argument for
it)............................Dr Holtz???