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RE: FARCICAL: Extinction due to "blue balls"
Eric Martichuski (firstname.lastname@example.org) wrote:
<B) If Birds have chromosomal sex determination, isn't it parsimonious to
suggest that dinosaurs did too (or, at least, theropods)? ISTM that such
a thing would be an _awfully_ big derived characteristic (if I'm using the
Not really. A corrollary to this that is similar and probably
descriptive of the sex-characteristic is that birds do not become
endothermic until after they developed wings and flight, as indicated in
the histology of *Confuciusornis* (De Ricqlès, A.J.; Padian, K.; Horner,
J.R.; Lamm, E.-T.; and Myhrvold, N. 2003. Osteohistology of Confuciusornis
sanctus (Theropoda: Aves). _Journal of Vertebrate Paleontology_ 23(2):
373-386). While crocs have temperature-dependant sex change, and modern
birds do not, this does not tell us that all animals leading to birds that
weren't crocs, including dinosaurs, were not temp-dependant ... it only
tells us that the change in birds, or the change in crocs from a primitive
and likely temp-based condition, changed in one of these lineages.
Jaime A. Headden
Little steps are often the hardest to take. We are too used to making leaps
in the face of adversity, that a simple skip is so hard to do. We should all
learn to walk soft, walk small, see the world around us rather than zoom by it.
"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)
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