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Re: Ah ha! That's where therizinosaurs came from



Jason Brougham <jaseb@amnh.org> wrote:

> Perhaps it is the very notion of adaptive explanations that I'm skeptical
> of. I have more faith in sober surveys of the distribution of characters
> rather than coming up with speculative explanations for the apparent
> pattern.


To me, these are two sides of the same coin.  Phylogenetic analysis
provides us with a distribution of characters.  Adaptive explanations
can then be inferred from the given distribution of characters.  As
one example, the transition from bipedality to quadrupedality has
occurred several times in Dinosauria.  But the adaptive explanation
for each individual transition may differ, depending on the clade
concerned (sauropodomorphs, thyreophorans, ceratopsians,
iguanodontians).  They are only "speculative" in the sense that they
are ultimately untestable.  That doesn't make them any less rigorous,
or any less scientific.


> A lot of elegant adaptive explanations, ones that thousands and
> millions of words have been written about, have been proven false by later
> evidence. The idea that dinosaurs (they didn't say non-avian then) went
> extinct because they were cold blooded and the world got too cool for them
> is just one such doozy.


That's science.  It doesn't really matter how many "wrong" adaptive
explanations came before.  As more and more discoveries emerge close
to the origin of avian flight, we can get a clearer picture of how and
why theropods took to the air.





Cheers

Tim