Clades, cladons, and "cladifications"

Nico Mario Franz nmf2 at CORNELL.EDU
Mon Jun 14 03:04:35 CDT 2004

>David Hull in his 1979 paper ("Limits of Cladism"; Syst. Zool.,
28:416-440) >pointed out the following dilemma: "no methods have been set
out thus far >which permit the inclusion of both sorts of information
[genealogy and >divergence] in a single classification in such a way that
both are >retrievable."

---This doesn't seem right. One can (and often does) map derived character
states along branches. These can convey precisely the kind of information
about "amounts of divergence" or "evolutionary distinctiveness" that, as
some have claimed, can't be expressed cladistically. One would hope that
if there really was a deep problem with expressing amounts of
transformation in cladistics (not just branching patterns), the method
wouldn't have caught on so broadly by students of evolution.

>The PhyloCode conference in Paris this summer is the next step in this
>doom and gloom scenario, and it makes me very nervous. But even if there
>were no phylocode, the elimination of paraphyletic taxa is not (and
never >was) the proper way to fight eclectic fuzziness. Hennig should
have stuck >with cladistic analysis (which has been a good thing, even
though not >always properly applied). His classification methods have NOT
been a good >thing, and an increasingly zealous application of such
methods are just >making things worse. ----- Not so cheerily, Ken Kinman

---I've tried to point out on one or two previous occasions that the
PhyloCode and cladistics sensu Willy Hennig Society cladistics are best
discussed separately. To my knowledge the WSH has held at least one
symposium and put out an entire volume (Botanical Review 2003, vol. 69, 1;
to collect its criticisms of the PhyloCode. It's all there for you to look
at, unlike cladists' views on likelihood inference, three-taxon
statements, or any other "perceived threat".

We're unlikely to sway any of the more flexible minds unless we get our
systematic group-taxonomy more refined. In light of the developments in
the WSH, I'd suggest speaking of PhyloCoders and cladists, but not assume
much overlap. Otherwise those who know the difference will rightly tune



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