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Re: Some thoughts on cladistics
Please, give us a break. Phylogenetic systematics certainly has no
exclusive patent in using phylogeny as a standard (far from it), but it
seems overly simplistic to use phylogeny as the overriding standard to the
exclusion of other views of relationship. You haven't cornered the market
on nesting either----both Benton and I use nested hierarchies.
At the risk of "oh no, here we go again", I like the example of
classifying Emperor Charlemagne, his siblings, and other "close" relatives
in a paraphyletic group. Weren't members of this family closely related (in
some ways to the exclusion of their distant descendants in the present day)?
Being one of Charlemagne's descendants myself, should I consider myself
more closely related to him than he was to his own brothers and sisters?
Granted the mixing of parental genes (in the intervening generations) makes
this far from a perfect analogy, but if you plug in an appropriate
organismal genealogy, many people come to the same conclusion I do:
It does not always make sense to classify an ancestor with all its
descendants to the exclusion of that ancestor's close relatives (especially
siblings). Strict cladism put too much weight on synapomorphies, at the
expense of plesiomorphies and anagenetic distance (and as imperfect as the
Charlemagne analogy is, it does give one a feel for the problems involved).
By the way, I love Martin's analogy about colors and wavelengths of
light. The Universe is a very fuzzy place when you look at things closely,
but dwelling on it and trying to micromanage it in cladistic fashion is
going to drive you nuts. Strict cladists obviously haven't driven the rest
of nuts yet, but they're heading in that direction and people are
increasingly declaring that enough is enough already.
Cladisto-eclectic centrist approachs to classification (Benton's, for
example) ARE nested and based on phylogeny----but they go beyond just
nesting and phylogeny, and reflect other aspects of relationship as well
(exemplified by the crude analogy of Charlemagne and his siblings). And
thus I think such an approach (once polished) will be more successful, more
utilitarian, more informative, and more stable.
.... we might as well *use* common descent, and actually classify
organisms with their closest relatives to the exclusion of all others.
Otherwise, why not classify whales as fish and bats as birds? Phylogeny is
a good, robust standard. Let's stick to it.
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