RE: Function Talks at Ostrom Symposium

["Stewart, Dwight" <Dwight.Stewart@VLSI.com>]

        -----Original Message-----
        From:   EctoDino@aol.com [SMTP:EctoDino@aol.com]
        Sent:   Friday, February 19, 1999 11:16 PM
        To:     dinosaur@usc.edu
        Subject:        Re: Function Talks at Ostrom Symposium


        Thomas R. Holtz, Jr said:
        > Others asked why would it be that a hypothetical
        >  diaphragm breathing would be incapable of being the ancestor of
birds.
         So did they let Ruben answer? It seems he answered that question in
the
        11/14/97 Science, p. 1269, where he says that a "diaphragm
ventilating
        ancestor would have necessated selection for a diaphragmatic hernia
in taxa
        transitional between theropods and birds. Such a debilitating
condition would
        have immediately compromised the entire pulmonary ventilatory
apparatus and
        seems unlikely to have been of any selective advantage."
        So is it answered in advance?

        --Jim

        @@@@@@@@@@@@@@@@@

           How certain is it that dinosaurs WERE diaphragm breathers?  And
why would the transition
        forms (IF dinosaurs were diaphragm breathers) be selected for a
diaphragmatic hernia?

        Dwight