[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]


 From: GSP1954@aol.com

 > I have sampled enough animals to show that it does not. ...
 > It is a fact that at least one bird and at least one mammal have
 > very long, EXTREMELY slender nasal tubes that plot well below the
 > reptile line calculated by Ruben et al. (Let's have some fun all
 > you dinofans. Guess what these two animals are. Hint. You have
 > very probably seen both of them at the zoo, although one is somewhat
 > rare.

For the mammal my best guess is the giraffe.
And for the bird, I would normally guess the flamingo.

Unfortunately neither of these is "somewhat rare", so one of my
guesses must be wrong.

 > Jones implies that I have to explain how tachymetablolic
 > animals can breath through such remarkably slender nasal passages. Not
 > so, the mere existence of such creatures proves that it works.

Besides, Jones failed to provide evidence that nasal diameter is rate
limiting in endotherms. (I know it is for *me*, but I have pathological
narial passages, so I do not count).  And, unless passage diameter is
rate limiting, the Jones' whole argument is simply irrelevent, as is
Poiseuelle's Law.

 > As for limb posture, I only claim that fully erect legs are diagnostic for
 > aerobic capacity above the reptile level. In doing so I do not assert that
 > erect limbs are REQUIRED for endothermy.

Quite, you are asserting the converse.

Your statement is
        Erect posture => tachymetabolism.

 From this one *cannot* conclude:
        endothermy => erect posture.

That is an error of logic - but one that many people make. It seems
there is a tendency to confuse "if" with "if and only if".

Note, I am perfectly willing to conced that the eivdence for dinosaur
endothermy is not (quite) conclusive yet, but it is still quite strong.
And if the new chinese compsognathid has actual body insulation (as
opposed to just a ridge of feathers on the back), then the case would,
IMNSHO, be pretty well concluded.

swf@elsegundoca.ncr.com         sarima@ix.netcom.com

The peace of God be with you.