Re: Re: synapomorphies

[Thomas_R_HOLTZ@umail.umd.edu (th81)]

>And yet...
>
>Most cladigrams I have seen tend to be constructed in the speciation model,=
> where the cladigram gets broader as one goes up the "tree" (like a maple). =
> Since Gould's punk eq has shown quite convincingly that the tree of life is=
> actually shaped like a pine, is it possible that most cladigrams portrays=
> an old fashioned view of evolution?

Since cladograms lack the time axis of Gould's figures, they are not really
comprable.  However, if you map a cladogram onto time (and include
hypothesized ancestor-decendant relationships) you may get something more
like Gould's.  For example, you'd get the vast diversity of Triassic
archosaurs going extinct, leaving only a few (but diverse) lines: dinos and
crocs.

Thomas R. Holtz, Jr.
Vertebrate Paleontologist
Dept. of Geology
University of Maryland
College Park, MD  20742
Email:Thomas_R_HOLTZ@umail.umd.edu (th81)
Fax: 301-314-9661
Phone:301-405-4084