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Dear all:
I think it is safe to say that no one can say what
killed each individual pterosaur. So then discussions like these are
heavily based in speculation and educated guesses. Comments were made that
because we have no idea about many factors involved in the K-T extinction of
pterosaurs that we should not deal with those factors or even the extinction
itself. It could be years before those factors are learnedby
paleontologists, or those factors may never ever be preserved in the fossil
record. So sould we suspend discussions forever? I this healthy
speculation is just that, speculation, and as lon gas everyone is aware of that,
then what's wrong with throwing ideas around?
And now to individual responses:
Ronald I Orenstein wrote:
In short, without the physiological information we
need we can only guess
at how effective Mesozoic reptiles were at gas exchange, or at dealing with oxygen stress, and therefore -- since we cannot establish the differences among different forms with any accuracy -- this is useless as an explanation for extinction. At the very least, before you can claim that a difference among taxa explains why one group survived and another did not, you have to be able to prove to that difference really exists. Demetrios Vital replies:
So if we cannot establish certain differences
between groups, such as the hemoglobin efficiency, then all we have left to
compare is the gross physical structure. And if guesses are the best we
can deal with, why shouldn't we deal with those educated guesses?
Yes, it would take an in-depth study to guage the
exact differences between taxa, but would you go into a study or discussion
assuming all taxa have the same respiratory abilities?
James R. Cunningham replied to me about how gliders
work fine in our (presumably) less dense atmosphere.
Demetrios Vital replies:
I didn't think of that. Of course, I never
claimed that the density change killed off pterosaurs, but wouldn't you agree
that despite the fact that pterosaurs could still fly, the change would affect
them enough to factor in?
Or, I could be completely wrong. But that's
what ideas and discussions like this are good for.
Peace out, Demetrios
Vital
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