[Taxacom] Mona Lisa Smile

[Thomas Lammers]

----- 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.

Tom Lammers

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