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Re: my two cents worth



        Stuart wrote (btw, welcome back :) :
>a) re: cladistics....there has been much debate about cladistics,and while
>cladistics are certainly useful,they won't be truly accepted until some form
>of 'universal standard" for cladistics is set.
        No other type of scientific experiment that I am aware of has a
'universal standard".  There are generally accepted practices, and
theoretical constraints which are established by scholars and published in
the literature. 

>For example,some governing
>body might have to be set up to moderate what data sets are to be used,to
>provide "bona fide" results.
        The only "governing body" of this sort that I am aware of in any
scientific discipline is peer review.  Yes, there are organizations like
IUGS, ICZN, and whichever group (UAS?) names the elements, but these are
largely committees of scientists which are established to regulate
nomenclature, not what data one is "allowed" to use.  I doubt that anyone
would suggest a committee to determine which chemicals one is allowed to mix
in a laboratory.

>I feel that cladistics is still far too
>arbitrary in that the programmer has carte blanche to assign whatever values
>he or she feels bear the most weight,dependant on personal preference or
>bias.
        Remove "programmer", replace with "trained scientist with years of
experience in his or her field".  Of course, you are right, and this is why
papers are subjected to peer review before publication, and to the
evaluation of the paper by other scientists after publication.  These
scientists may judge the work as they see fit.
        Note that many cladists simply weight all characters equally, in the
hope of note contaminating the dataset too much.

>I have already seen many cladograms (all VERY different) for theropod
>dinosaurs. How can we make things more consistant?
        *Why* should we make things more consistant?  We cannot know what
*the* phylogeny is.  A cladogram represents a phylogenetic *hypothesis*, and
these change with new data. These different cladograms represent different
takes on the phylogeny, which is unknown to us.  Different hypotheses,
theories, and finding a better fit for the data is what science is all about.
        Phylogenetic systematics is designed to be as flexible as our ideas
of evolution.  Adding rigidity (I believe "stability" is how Mayr put it) is
certainly not going to improve it.

>b) I still have some difficulty with the statement "birds are dinosaurs". I
>feel that birds are still birds (class Aves) and dinosaurs are still
>dinosaurs.
        Then you are using a traditional approach to taxonomy, and I guess
you can say whatever you want.

>Can we perhaps refer to the avian-like dinosaurs as just that,and
>not birds...at least yet!
        Dinosauria includes Aves, Bird does not necessarily include all
dinosaurs.

        Ok, let's not start up this debate again.  I'd be happy to continue
this off list.  :)

        Wagner
+--------------------------------------------------------------------------+
| Jonathan R. Wagner                    "You can clade if you want to,     |
| Department of Geosciences              You can leave your friends behind |
| Texas Tech University                  Because your friends don't clade  |
| Lubbock, TX 79409                               and if they don't clade, |
|       *** wagner@ttu.edu ***           Then they're no friends of mine." |
|           Web Page:  http://faraday.clas.virginia.edu/~jrw6f             |
+--------------------------------------------------------------------------+