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Respiratory turbinates vs. the rest of the world
Okay, I just had to put my two cents worth into this argument. I don't care
what kind of statistical qualifications you might have, any idiot can tell
that Ruben's sample size is inadequate. To use this list's favourite
example, if you have a thousand marbles, half of which are red and the
other half black, picking only three could very easily result in them all
being black on the first try and all red on the second. What does this tell
us? Obviously nothing of any consequence, except that the sample size is
not statistically significant.
Furthermore, even if Ruben's sample size were adequate, this does not come
anywhere near proving that respiratory turbinates are a prerequisite for
endothermy. Let's compare this line of evidence to Jones' pet whipping
post, dinosaur posture. He says that because there are endotherms with
semi-sprawling posture there is no link between posture and metabolism.
However, this is only true if fully-erect posture is considered to be a
prerequisite for endothermy. In fact, it is the other way around. If you
were able to find an ectotherm with fully-erect posture, that _would_ be a
very strong argument against this line of evidence. However, there is no
such animal extant (and extant fauna is all we can go on in this case).
On the other hand, Jones does consider RT to be a prerequisite for
endothermy. Therefore, in order to disprove this line of evidence, all we
need do is look for endotherms that lack them. Do such animals exist? As
has already been stated many times on this list, they do, even though they
might be the minority in the modern fauna. Conclusion? Endotherms without
RT exist, therefore the latter is _not_ a prerequisite for the former. On
the other hand, _no_ ectotherm with fully-erect posture is known, so
endothermy _might_ be a prerequiste for such posture.
We should also remember that the respiratory systems of dinosaurs are
somewhat different to those of mammals. They may not even have been nasal
breathers! Yes, mouth breathing _does_ result in greater moisture loss.
However, the mammalian method of excreting uric acid also results in far
greater water loss than the reptilian one, yet they still do it.
I also have a personal anecdote to offer here. Being a sinusitis sufferer,
I am by preference a mouth breather. Yet I was always under the impression
that I was endothermic. Indeed, I was a champion sprinter in primary
Finally, even if there _were_ more weight to the RT argument, I fail to see
how this single line of evidence could possibly outweigh all the other
lines of evidence in favour of dinosaur endothermy. Jones asks why it is so
important that dinosaurs be endothermic. We might as well ask him why it is
so important that dinosaurs be ectothermic. It is _NOT_, I repeat, _NOT_
good science to assume that dinosaurs were ectothermic until they are
absolutely proven to have been endothermic. It is good science to assume
_nothing_, and go with what the evidence suggests. I am certain that any
unbiased observer would _have_ to conclude that the current weight of
evidence is MASSIVELY in favour of dinosaur endothermy.