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Date: Sat, 12 May 2001 13:14:40 -0700 (PDT)
From: "Jaime A. Headden" <qilongia@yahoo.com>
To: phylocode@ouvaxa.cats.ohiou.edu
Cc: kinman@hotmail.com
Subject: Re: Nipping the bud
Ken Kinman (kinman@hotmail.com) wrote: <"Nipping the bud" is the ultimate problem with pure phylogenetic taxonomy. Even many cladists will admit that speciation is a budding (paraphyletic) process. Therefore paraphyletic groups are a superior model.> This sounds like generalizing a specific problem: whereas the paraphyletic speciation of organisms is true to a certain degree, applied generally it fails to confirm speciation within higher taxa. That speciation is a budding principle is a paradigm true only so far as we can find the population. Amphibians did not give rise to amniotes, so nesting one within the other is a foolish excercise. Amphibia is an explicit group whose ansecors amy or many not have been that same as Amniota's was. This means practically nothing except that these two groups are explicity sister to each other until we find the whole and intact envolutionary sequence of the speciation event itself that caused to arise the groups we apply these names to, paraphyletic or not. <Sister groups are a Hennigian convention (not based in reality at all), but they are a useful convention because extinction and the rarity of fossilization has given us gaps that make sister groups seem real and a useful approximation of real clades.> Sure, I agree 100%. And since I can make a pure parsimony statement that man evolved from apes that are derived from the chimpanzee, we must therefore call ourselves a subgroup of *Pan*. That *Pan* is a subgroup of another one... <In reality the tree of life is a nested series of paraphyletic groups that we can never discover, so the best we can hope is to recognize the most useful set of [paraphyletic] groups and exgroups (clades) that we can.> Let me phrase this into a more parsimonious statement: "The tree of life appears to be a nested series of groups whose ancestors we can never discover, so the best we can hope is to recognize the most useful set of relationships of these few explicit groups that we can." Paraphyletic arrangement is the assumption, and should be considered differently than the "nesting" of groups, since this is an assumption of actual relationship. ===== Jaime A. Headden Aaaaaaaaaaaaaaaaaaaahhhhhhhhhhhhhhhhhhr-gen-ti-na Where the Wind Comes Sweeping Down the Pampas!!!! __________________________________________________ Do You Yahoo!? Yahoo! Auctions - buy the things you want at great prices http://auctions.yahoo.com/