paraphyly & polyphyly

[Ken Kinman]

Rienk,
     You might find this surprising, but I completely agree with you.  We
should avoid using both paraphyletic and polyphyletic groups (with a few
clearly "branded" exceptions, such as viruses, which need to be classified,
whether one regards them as living or not).
      However, semi-paraphyletic groups should NOT be avoided, and they are
necessary for utility and stability.
They bridge the gap between traditional paraphyletic groups (which I do
reject) and holophyletic groups (i.e., cladistically monophyletic groups).
The strict cladist's distinction between "monophyletic" and
"nonmonophyletic" has thus been rendered out-of-date, unnecessary, and
henceforth misleading.
                   ----Ken Kinman
P.S.  There is a copy of my book at the University of Leiden or the
University of Amsterdam (I've forgotten which).  The Kinman System was
designed to handle even the huge insect families and genera.
"Try it, you'll like it."  :-)
***********************************************************
>From: "Jong, R. de" <Jong at NATURALIS.NNM.NL>
>Reply-To: "Jong, R. de" <Jong at NATURALIS.NNM.NL>
>To: TAXACOM at USOBI.ORG
>Subject: paraphyly & polyphyly
>Date: Tue, 8 Feb 2000 08:36:50 +0100
>
>James Adams wrote:
> >Ah, but you are missing the *most important* difference between
> >the two terms -- that the paraphyletic group, though not including
> >all descendents, *does* include the common ancestor, whereas a
> >polyphyletic group does not.  This *is* an extremely important
> >distinction, which I do not feel that virtually anyone doubts on this
> >list.
>
>And Curtis Clark wrote:
> >It is extremely important, easy to make in theory, but often not easy in
> >practice.
>
>So I may be the only one on this list who does doubt the extreme importance
>of the distinction between paraphyly and polyphyly. I know there are
>several
>definitions of these terms, but as far as I can see they all boil down to
>the following: if I STATE that the group orchid+elephant includes their
>most
>recent common ancestor, the group is paraphyletic, if I DON'T STATE it, it
>is polyphyletic. My point is not that we can, in theory, make a distinction
>between paraphyly and polyphyly, but that it is useless as we should not
>use
>paraphyletic or polyphyletic groups at all.
>
>Rienk
>
>----------------------------------------------------------------------------
>-----------------------------
>For two important meetings in 2000, visit
>http://nhncml.leidenuniv.nl/symposia/
>
>_______________________________
>Dr Rienk de Jong
>Department of Entomology
>National Museum of Natural History
>PO Box 9517
>2300 RA Leiden
>Netherlands
>phone *31 71 568 76 52
>fax  *31 71 568 76 66
>e-mail: jong at naturalis.nnm.nl
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