[Taxacom] Hatfields and McCoys (was: Phylocriminetics)
kennethkinman at webtv.net
Sat Jan 1 20:43:10 CST 2011
I really like your car analogy. I certain agree that
some strict cladists are guilty of short-changing or even totally
skipping the theory step (which can be particularly harmful when looking
only at molecular data). However, they seem to be just part of the bad
half of a bell-curve of strict cladists (below average in quality and
However, on the high end of the good half, there are some truly
outstanding strict cladists (Peter Stevens comes to mind) who do
excellent work theorizing and integrating multiple lines of evidence.
Thus the complaints I have with APG classifications are simply some of
their overlumping (to eliminate paraphyly), and no formal Classes of
angiosperms (Magnoliopsida, Liliopsida, and Rosopsida) because the first
is paraphyletic (or semi-holophyletic in my angiosperm classification).
So I think we have to give credit where credit is due, and not
paint strict cladists with too broad a brush (beyond their shared
paraphylophobia). There are even some PhyloCodists who do good work,
even though I think PhyloCode is a horrible idea. So when it comes to
evaluating the value of cladistic analyses, I do not discrimate on the
basis of whether it was done by a strict cladist or not. There are good
and bad workers on both sides of that divide.
So when it comes to angiosperms, I largely base my
classifications on work done by strict cladists. But unlike them, I
reintroduce some semi-paraphyly (semi-holophyly), and also reverse some
of the paraphylophobic overlumping that seems counterproductive. I
still think this approach can meet the needs of a wide variety of users
(both strict cladist and "evolutionary") and maximize stability at the
same time. Some might call such classifications a "mish-mash" or
unnatural or whatever. But I really believe that such middle ground is
the future of systematics (once strict cladists finally admit the need
and desirability of using the most useful of
semi-paraphyletic/semi-holophyletic taxa like Prokaryota, Protista,
Amphibia, Reptilia, among others at lower taxonomic levels as well
(e.g., the brown bear species).
But I certainly agree with you that too much cladistic analysis
alone can stop short of the much needed theoretical analysis (especially
those based on molecular data alone). The Three-Domain classification
of life is (in my opinion) one of the most horrible examples of strictly
cladistic classification that largely resulted in a lack of data, lack
of theory, and an attempt to avoid the paraphyly of Prokaryota. A
semi-holophyletic taxon Prokaryota is the best solution, and whether to
call it a Kingdom, Superkingdom, or Empire is not as important as
recognizing it is a natural and very useful taxon.
Richard Zander wrote:
No, Ken, I am not a cladist (as you suggested I was). I use
sister-group analysis as part of getting information about evolution.
Cladistics is like diagnosing what's wrong with your car by listing all
the parts and their condition. Sometimes you can see what's wrong from
that (e.g. unclean spark plugs), sometimes you can't (such as when
slightly faulty parts interact), but in no case can you figure out why
the parts got faulty in the first place without thinking about that and
making a theory (e.g. poor maintainence, bad gasoline).
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