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RE: CNN:dino-birds are not father of birds



If dogs/wolves are any example; teeth can change fairly rapidly.  We turned
wolves into
semi omnivorous dogs with the diet we fed them.  Domestic dogs can (maybe
not SHOULD) eat
a wider variety of foods than can wild dogs or wolves.  Some of their teeth
have adapted to
handle more fruits & vegetables.  I don't recall the date, but the Learning
Channel had one
of their "Everything You Wanted to Know About" specials about canines &
canine evolution.
Several dog experts said the evidence indicated that wolves had changed into
domestic dogs in
only 25 years, including the teeth altering to deal with diet changes.  So,
I would take differences in teeth as very iffy prove of a lack of a link
between modern birds & avian dinosaurs.  Of course, I realize that the
thought that their beloved modern birds might
be related to "brutish dinosaurs" still raises hackles in some circles.  :-)
But, then, that
image of dinosaurs is pretty out-of-date too.  So, is the objection here
merely to a direct
connection, or is it to the dino-bird link period?  Would the idea of
unknown intermediate 
forms be more acceptable?  Look at the difference between Bonobo chimp teeth
& ours & there
is only about a 1.4% difference in the DNA.  

Regards;
Dwight


        -----Original Message-----
        From:   Dann Pigdon [SMTP:dannj@alphalink.com.au]
        Sent:   Saturday, February 27, 1999 5:48 PM
        To:     dinosaur@usc.edu
        Subject:        Re: CNN:dino-birds are not father of birds

        For the record I tend to agree with the subject line, however...

        Betty Cunningham wrote:
        > 
        > Scientists: Dinosaur-Birds Are Not Father of Birds (2)
        > Xinhua      27-FEB-99

        > SNIP

        > However, Hou rejected the theory of a direct connection between
        > dinosaur-birds and modern birds.
        > 
        > "The two short-armed specimens have saw-like teeth that were flat
and
        > sharp, with deep bulbous roots, unlike the modern bird's conical
shape,"
        > Hou said.

        Surely other theropods with conical, unserrated teeth (such as
        spinosaurs) were themselves descended from serrated blade-toothed
        ancestors? I'm not saying that there is a direct line of descent
from
        these "dino-birds" to modern avians, but I'd have thought that teeth
        could change (or be lost) fairly quickly, depending on changes in
        diet. Are teeth really such a good indicator of ancestor/descendant
        relationships, especially over extremely long time spans? 

        -- 
        ____________________________________________________
                Dann Pigdon
                GIS Archaeologist
                Melbourne, Australia

                Australian Dinosaurs:
                http://www.geocities.com/capecanaveral/4459/
                http://www.alphalink.com.au/~dannj
        ____________________________________________________