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Re: nitpicky cladistics



I just returned to my office after last week and read the interesting
responses to the original :-S posting.

Sometimes I just don't seem to make my questions clear.  Like another of
my postings that resulted in a vat of scorn being emptied upon us
cockroaches by GSP, in spite of the fact that I was familiar with at
least some of his writings on the subject and was already convinced that
giant dinosaurs would not cook in their own juices--that had not been my
point.

I have just a few minor comments on nitpicky cladistics.  You see, I
haven't been completely assassinated yet--I'm like that poor sap in
Reservoir Dogs who got shot and spent the remainder of the movie
thrashing about on the floor, trying to die, but just couldn't.

(The quotes are all rekeyed--any typos are mine.)

Wagner said:  ". . . morphological distance . . . has *nothing* to do
with the phylogeny . . . [emphasis his] . . . Morphological distance is
not useful information to anyone except someone who needs a card
catalog."  I think, however, if a tally could be made, we would find that
morphological distance DOES reflect phylogeny most of the time.  And, if
you are interested in what physically exists in the world, you will use
morphological distance to find out.  Animals and plants are everyday
objects that we can see all around us.  But cladists define things that
have no concrete reality, and then say that _only_ those things are real.
 This just won't play in Peoria.

Holtz, referring to Maniraptora, said: "It is a taxon defined as birds
and all taxa closer to birds than to _Ornithomimus_."  To which Wagner
added, "Again, the character state distribution is how one finds clades,
not how one defines clades."  This reminds me of an Aristotelian ideal
that we can only envision, and then hope to find out how it is
manifested, albeit imperfectly, in the real world.

Cladists are really just saying that life has evolved.  So, since birds
have evolved, they must have evolved from something.  Whatever that
something might be, it, along with birds, are maniraptors.  Yes, this is
_real_, but I think that a tautology lurks somewhere in there--I just
can't put my finger on it.  Nevertheless, I see a _real_ discontinuity in
this event.  Wagner said:  ". . . when birds evolved, the rest of the
dinosaurs didn't suddenly up and become something different.  So why
should their designation change because of what their progeny became?"
The perspective there seems to be backwards.  When birds evolved, _they_
were the ones that up and became something different.  So we don't rename
the ancestors, we rename the descendants, calling them birds.  Even
though the ancestor-descendant chain is complete, there was a major
discontinuity in the history of life at that transition.  You can't
_define_ it away!  What's more, it is morphological distance that allows
us to recognize this _real_ discontinuity.

There is clearly a conflict of value systems here, which is a
philosophical disagreement that will not likely be resolved by continued
debate, since we cannot even agree on what is "good" and what is "bad."
I'm getting a headache, too.


*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
Norman R. King                                       tel:  (812) 464-1794
Department of Geosciences                            fax:  (812) 464-1960
University of Southern Indiana
8600 University Blvd.
Evansville, IN 47712                      e-mail:  nking.ucs@smtp.usi.edu