Re: Martin 2004 critique (somewhat lengthy)

["Jaime A. Headden" <qilongia@yahoo.com>]

Martin Baeker (martin.baeker@tu-bs.de) wrote:

<Cladistics is not phylogenetic nomenclature!>

  Indeed. However, contrary to what David Marjanovic said, it is not
phylogenetic systematics, either. Cladistics is a system of programming used to
find a match between any two sets of data and their relationship to other sets
of data in couplets, or in further defined patterns of arrangement. This, while
applicable to systematics and phylogeny, is really the tool used by that method
of phylogeny recovery. Cladistics has other uses, including simply finding
parsimony matches in anatomy using binary or supernumerary systems and, in gene
studies, corellations among nucleotide sequences that suggest homology and
homogeny. Any phylogenetic interpretation is secondary to the process called
cladistic methodology.

  To underscore this, I would remind fellows the few (so far) studies that have
undertaken use cladistics to find relationships of a single bone, including
Frankfurt and Chiappe on the El Brete cervical attributed to the
segnosaur-oviraptorosaur group, and Naish et al. on their modification of this
study to test the similarity of the *Thecocoelurus* holotype. This method of
application is very different in that it doesn't attempt to find a phylogeny,
but as a means of relating similarity (the actual goal) into a visual topology:

  "These are more similar to one another because A, B, and D, but C is found in
more than these two, so is less likely to be phylogenetically informative."

  Thus I can use THAT and frame a phylogenetic interpretation, but that wasn't
the goal of the study. Currently, I am looking at single element topologies and
how they relate to phylogenies. because one is looking at a single element, a
humerus (say) can reward the observer with something like 55 discrete bistate
and polystate characters. Expression of a crest, shape of a flange, orientation
or shape of a condyle, etc.

  Cheers,

Jaime A. Headden

  Little steps are often the hardest to take.  We are too used to making leaps 
in the face of adversity, that a simple skip is so hard to do.  We should all 
learn to walk soft, walk small, see the world around us rather than zoom by it.

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)

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