the "p" word (paraphyletic)
kinman at HOTMAIL.COM
Thu Sep 16 12:08:45 CDT 1999
> >>>I am wondering if you would consider the four kingdom system to be
>"extreme" paraphyly as well. Having Metazoa and Metaphyta arising from
>Protista would be no more paraphyletic than mammals and birds arising from
>reptiles. I don't use this kind of double paraphyly very often, but a few
>eclecticists don't like anything beyond single paraphyly (and of course,
>strict cladists don't like any at all). ---------Ken
> While we're at it, mammals, birds, and reptiles are all paraphyletic to
>osteichthys. Personally, I have no problem with paraphyly. But then I
>work with birds and don't like calling them reptiles, either.
Actually, you have a lot of company. My experience is that the vast
majority of biologists find some paraphyletic groups perfectly acceptable
(and of course, it would be very difficult communicating with non-biologists
without them). Among systematists, it would probably still be a majority,
but not nearly as "vast", and of course, if you are at the American Museum
you would probably be in the minority. I should add that I define a strict
cladist as one who regards paraphyletic groups as unnatural and do not
recognize them as valid taxa. Many eclecticists ("evolutionary
taxonomists") use cladistic analysis as a tool, but do not feel their
cladograms must be strictly reflected in their classifications (and thus
allow an additional component of divergence).
Strict cladists, being in a minority, have naturally been more vocal
about classification methodologies, and this probably leads to the
impression that they are a bigger group than they really are. But there
seems to be more of a backlash in recent years against strict cladism,
especially among botanists. As always, the silent majority probably pay
little attention to the debate, roll their eyes and go about their work
(which is no doubt a good thing).
Since this situation isn't going to change much anytime soon, I am
optimistic that the limited use of semi-paraphyletic groups will eventually
catch on (even among some strict cladists, when they see that
paraphyleticisms no longer lead to the loss of sister group information).
Only time will tell.
P.S. Speaking of osteichthyes, the "fish" cladists may be happy to hear
that I classify virtually all of their groups cladistically, although I had
little choice but to treat Class Sarcopterygea as a semi-paraphyletic group
(with a marker for its Tetrapod descendants).
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