[Taxacom] Endless debate
Richard.Zander at mobot.org
Tue Apr 7 08:54:06 CDT 2009
Well, actually, now that this has come up, cladistics is just a way of approaching the "paraphyletic" Darwinian Tree of Life (p. 95 of Darwin's paperback) which has one taxon giving rise to another.
Saying cladistically that "these two taxa are more related to each other than either is to a third" is just a way of clustering the results of descent with modification of taxa (as opposed to traits, but that is a different problem). Descent with modification is evolution, not the bifurcating results of a cluster analysis, although the results of cluster analysis can help us understand evolution. If we had lots of information on descent with modification, which would be better, a sister-group classification or some kind of grade-based classification? Must we choose?
The Linnaean classification is what we have and is closest to a general-purpose classification if we mix all our interpretations of descent with modification, both sister-group and ancestor-descendant relationships into it, explaining our reasons, methods and data elsewhere.
Richard H. Zander
Missouri Botanical Garden
PO Box 299
St. Louis, MO 63166 U.S.A.
richard.zander at mobot.org
From: taxacom-bounces at mailman.nhm.ku.edu on behalf of Curtis Clark
Sent: Mon 4/6/2009 10:18 PM
To: taxacom at mailman.nhm.ku.edu
Subject: Re: [Taxacom] Endless debate
The "paraphylocode" I propose would consist of
nothing but grade taxa, delimited by key innovations. It would be to
grades as phylocode is to clades. I disagree with grade-based
classification, but I have suggested a way to make it rigorous, if
anyone were interested, which it seems no one is, because all of you who
support grade-based groups seem content to mix them willy-nilly with clades.
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