Re: Evolution:Small Scale/Grand Scale

[Skip Dahlgren <SDAHLGREN@liblan.uams.edu>]

On Fri, 19 May 1995 14:23:14, Tom Holtz commented:

> Under a "gradistic" system, you would be correct. But, as a few of you may
> have noticed (;-)), I follow a cladistic taxonomy, in which names do not
> describe evolutionary grades (similar levels of development), but clades
> (an ancestor and all of that ancestor's descendants).  Since birds descend
> from the common ancestor of all dinosaurs, and dinosaurs descend from the
> common ancestor of all reptiles, than cladistically, birds are dinosaurs
> (i.e., members of the clade Dinosauria) and dinosaurs are reptiles (i.e.,
> members of the clade Reptilia)

I don't mean to sound flippant, but how far can you carry such cladistic 
logic?  In theory, there is only one clade: Protozoa; we're demonstrably all 
descendants of some Urprotozoan, right?  Obviously, you wouldn't carry the 
process to such an extent, but where *do* you draw the line?


Skip Dahlgren
Applications Programmer, Office of Educational Development
University of Arkansas for Medical Sciences
Phone: 501/296-1087; FAX: 501/686-7053 (new FAX#!)
e-mail: sdahlgren@liblan.uams.edu; bcsskip@aol.com
-ex-archaeologist; lifelong afficionado of dinosaurs and their latter-day kin
"Cross-platform computing is much safer than downhill!"  :)