[Taxacom] Mona Lisa Smile
lammers at uwosh.edu
Sun Jul 30 21:19:32 CDT 2006
----- Original Message -----
From: pierre deleporte <pierre.deleporte at univ-rennes1.fr>
> By the way, methods for achieving such a classificatory goal are well known: they consist, by definition, in phenetic clustering.<
Yes, I've used it a fair bit in my work, at the population/species level. At those levels, I believe it is the logical method to use.
>> And if you could specify at little bit more which kind of "overal similarity"<<
I want a classification that takes into account ALL aspects of a species biology: morphology, chemistry, ecology, etc. If the phrase "overall similarity" bothers some, I'll rephrase it as, "the most things in common."
> It also seems obvious that you are looking after one single classification, which you try to conceive as an acceptable compromise for general use. It looks at first sight like a kind of Kinman system combining
paraphyletic and monophyletic groups, but, if I understand well, with the striking difference that you explicitly privilegiate overall similarity, hence accepting occasional monophyletic grouping as a side effect
(when Ken's > system is strictly phylogenetic, with some paraphyletic namings).<
In supraspecific classifications, I think evolutionary history must be the guiding basis. As I said, more often than not, this should result in classifications in which the taxa grouped together have the most tings in common. I will accept only monophyletic groups -- in the REAL original meaning of "monophyletic" -- i.e., all members of the group share a common ancestor. When some descendents of a copmmon ancestor have diverged quite a lot, I kick them out of the group. What is left behind is still monophyletic in my book. Anyone who banishes paraphyletic groups is ignoring how evolution operates.
> But my precise point is: for which purpose do you consider your system to be "the best classification"?<
For ALL purposes, biological and otherwise. If "best" offends, substitute "most useful." The only thing that would carry more information than such a classification is a phylogeny. But phylogenies make clumsy classifications.
>>Why not everybody his own optimal system rather than an inevitably sub-optimal, if not far from optimal, compromise?<<
So that we have a common touchstone for communication. So that we do not recreate the Tower of Babel.
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