Re: dinos and birds

[Mickey Mortimer <Mickey_Mortimer111@msn.com>]

pheret wrote-


> and yet another thought.  i always think that what really got the dinos
> was a virus.  it's the only possible thing i can think of that would wipe
> them out completely (as far as we know).  that is one of the things that
> also makes me, grudgingly, think birds may be reptiles . . .

Birds are reptiles due to phylogenetic taxonomy (the recent practice of
defining the content of groups of organisms based on their relationships to
each other).  Reptilia is defined (roughly) as the most recent common
ancestor of modern lizards, snakes, turtles, crocodilians, the tuatara and
all its descendants.  Birds happen to be some of those descendants, so they
are reptiles.  It's not just a matter of personal preference anymore.

As for the virus theory, it fails to explain why so many non-dinosaurian
groups went extinct too.

> the thunderbirds were around after the dinosaurs, right?

Yes, Brontornis lived in the Early to Mid Miocene, and the earliest
phorusrhacids lived in the Mid Paleocene.  The other known large extinct
birds (ratites, gastornithids and dromornithids) also lived in the Tertiary.

> do palentologists, et al., study their fossils with the realization that,
> especially if it is just one example of a creature, that it could be a
> fluke?  and this is not asked sarcastically!

While that realization is at the back of our minds, I'd say we study fossils
assuming that they represent the norm, barring evidence to the contrary.
It's a more scientific way to approach things, as other more theoretically
inclined members of the list could no doubt explain better.

Mickey Mortimer
Undergraduate, Earth and Space Sciences
University of Washington
The Theropod Database - http://students.washington.edu/eoraptor/Home.html