Re: Gaia theropod follow-up: a "new" phylogeny

["Jeffrey Martz" <jeffmartz@earthlink.net>]

Tracy Ford wrote...
>This is one area I disagree with. ANY manipulation of the data from what
>PAUP has given is wrong. It's abusing the system/program that it was made
>for. The author (here will be the Scientist) will run the program. He will
>get anywhere from 12 to 100 different trees. Which one is right? The author
>decides the most parsimonious one (MPO, how does HE decide that?). But the
>MPO isn't quite to his liking. So he re-codes some things, re classifies
>others and there is the MPO, but it isn't the one the computer put forth.
He
>just manipulated the information to his liking.

    The implication here is that the author has a specific phylogeny in mind
that he is trying to get by tweaking the data.  This is not neccesarily the
case.  If he suspects that taxa were placed together based on characters
susceptible to homoplasy, he can run the set again without those characters
to see what happens, and may be completely surprised by the result.

>You have to be able to use geology. You
>can't have an ancestor after its kin.

    Take any vertebrate group with a long history, and plot out all the
individual fossil occurrences on a geologic time scale, and it will beome
clear that the majority of the history of that group is empty space with no
fossils filling the gap.  Its pretty likely that those gaps will include the
earliest occurrences of the group.  The argument that we can a group in the
fossil record appearing after the group that supposedly gave rise to it
because the ancestral group is lacking its earliest members in the fossil
record isn't just a excuse for a phylogeny contradicting the known fossil
occurences.  Its a pretty fundamental aspect of the fossil record.


LNJ
*****************************************************************
It is our duty to make the best of our misfortunes and not to suffer passion
to interfere withour interest and the public good.
-George Washington

It is your business when the wall next door catches fire.
-Horace
*****************************************************************
Jeffrey W. Martz
Graduate student, Department of Geosciences, Texas Tech University
3002 4th St., Apt. C26
Lubbock, TX 79415
http://illustrations.homestead.com/Illustration.html