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Classification: A Definition

Awhile back, Mike Keesey wrote:

As David pointed out, phylogenetic nomenclature is not classification;
it's an alternative to classification.

I must admit, this comment has been nagging at me, but I've been unable to get on a computer long enough 'til now to ask further about it. Now, I hain't got nuthin' agin phylogenetic nomenclature -- as a matter of course, I find it far superior to the ol' Linnean system and have happily abandoned the latter -- but I'm curious about its perception as not being a form of classification. Considering the following more or less typical definitions of "classification":

1: the act or process of classifying. 2 a: systematic arrangement in groups or categories according to established criteria; specifically : taxonomy b: class, category

1. The action of classifying or arranging in classes, according to common characteristics or affinities; assignment to the proper class.
2. The result of classifying; a systematic distribution, allocation, or arrangement, in a class or classes; esp. of things which form the subject-matter of a science or of a methodic inquiry.

(Noting, of course, that "class" here is used in a philosophical sense, not a Linnean one.) I don't quite see how phylogenetic nomenclature -- well, phylogenetic systematics, that is, which is technically distinct from but inextricably linked to phylogenetic nomenclature (one is kind of useless without the other) -- doesn't meet these criteria. The nomenclature is a means of providing names to entities (classes) that exist/are ascertained to exist based on evolutionary descent; this differs from the Linnean system of providing names to entities based on a few gross physical similarities, sans regard to evolutionary relationships. Either way, it's using a set of criteria to designate (i.e., name) groups. Perhaps not categorization per se -- certainly not in the Linnean sense of ranks! -- but still seems to me to be classification. _Tyrannosaurus_ is still classified as a member of the Coelurosauria, Tetanurae, Theropoda, Dinosauria, Archosauria, Tetrapoda, Vertebrata, etc., though not for the same reasons (and obviously not some of the same groups) as it had been previously. I guess I'm not seeing how determining a taxon to be in some set of clades doesn't qualify as classification. I can see that phylogenetic NOMENCLATURE is _in itself_ not classification (not without the systematics part), but it also isn't an _alternative_ to classification. Or am I missing the point here?

Jerry D. Harris
Director of Paleontology
Dixie State College
Science Building
225 South 700 East
St. George, UT  84770   USA
Phone: (435) 652-7758
Fax: (435) 656-4022
E-mail: jharris@dixie.edu
and     dinogami@gmail.com

"Trying to estimate the divergence times
of fungal, algal or prokaryotic groups on
the basis of a partial reptilian fossil and
protein sequences from mice and humans
is like trying to decipher Demotic Egyptian with
the help of an odometer and the Oxford
English Dictionary."
-- D. Graur & W. Martin (_Trends
in Genetics_ 20[2], 2004)