Re: Re: Birds and dinosaurs

[Stan Friesen <swf@ElSegundoCA.ATTGIS.COM>]

>From: Thomas_R_HOLTZ@umail.umd.edu (th81)
 > Is stability something that must be achieved, even at the cost of obscuring
 > our knowledge of relationships?  If so, why put whales in Mammalia, when
 > they are equally "stable" in Pisces? 

Two points:

1. The knowledge of the relationships is not obscured, it is
available in the cladogram.

2. Even a cladistic classification "obscures" some knowledge,
knowledge of anagenesis, which is as much part of evolution as
cladogenesis.

The point is a good classification *summarizes* the data, note
replicates it.  One simply has to choose which data are to be
dropped and which to be represented.

A pheneticist bases a classification purely on morphology.

A cladist bases a classification purely on branching patterns.

An evolutionary taxonomist bases a classification on a balanced
combination of branching and morphology.

Nobody here is proposing making stability the *sole*, or even
the *primary* criterion for classification.  Al we are suggesting
is that it is *one* of several criteria that need to be evaluated.

 > Obviously, no serious systemicist has
 > done so for over one hundred years (and, in fact, Pisces was long ago
 > abandoned because of its paraphyletic status).

Not by me.  I still use Pisces.

Fish is still a good taxon, well seperated from others.

swf@elsegundoca.attgis.com              sarima@netcom.com

The peace of God be with you.