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RE: Caudipteryx not a bird and more from APP
> From: Dora Smith [mailto:email@example.com]
> Sent: Thursday, February 03, 2005 8:02 PM
> To: firstname.lastname@example.org; Mickey_Mortimer111@msn.com; email@example.com
> Subject: Re: Caudipteryx not a bird and more from APP
> You've convinced me that caudipteryx was not ancestral to birds; but I'm
> having trouble with the idea that this proves that archeopteryx was
> ancestral to birds.
By no means mix up the two hypotheses: they are not connected!
One can easily accept that a) Caudipteryx is an oviraptorosaur while still
accepting that b) Archaeopteryx is not directly on the
line to modern birds. These are perfectly compatible hypotheses. The important
thing would be what the best evidence shows.
And in most studies Archaeopteryx is closer to birds than either is to
Caudipteryx, but that doesn't mean that Archaeopteryx is
ANCESTRAL to modern birds. After all, Utahraptor is also closer to birds than
is Caudipteryx in most recent studies, but nobody
suggests (for a wide variety of reasons) that Utahraptor is directly ancestral
to modern birds.
One of the most important aspects of the cladistics revolution is the
recognition that the chance that we have actual sampled the
real, true, honest-to-goodness ancestral population from which another group we
are interested is vanishingly small. The geologic
record is very spotty, and all other things being equal we wouldn't be able to
tell directly if a particular fossil represents a)
the population directly ancestral to the other group in question or b) a close
relative to the population directly ancestral to the
So instead of doing the old-fashioned ancestor hunt, we instead search for
*patterns of recency of common ancestry*. These patterns
are inferred by the basic evolutionary premise of descent with modification.
I hope this helps,
Thomas R. Holtz, Jr.
Department of Geology Director, Earth, Life & Time Program
University of Maryland College Park Scholars
Building 237, Room 1117
College Park, MD 20742
Phone: 301-405-4084 Email: firstname.lastname@example.org
Fax (Geol): 301-314-9661 Fax (CPS-ELT): 301-405-0796