Paraphyly - monophyly mad

Subject: RE: BRYONET: Paraphyly
Date: Wed, 12 Nov 2008 16:11:41 -0600
From: Richard Zander <Richard.Zander@mobot.org>
To: <bryonet-l@mtu.edu>

BRYONET

I appreciate your wonderful response, Efrain! I used the phrases
"monophyly-mad" and "innocent students" only to encourage contribution
to the discussion. Outrage is a great way to elicit sharing of
information and opinions, which drives genuine advances.

Efrain wrote:
"I was converted to think in terms of phylogenetic theory and methods as
a way to decide among competing hypothesis (Hs) of biological groups as
lineages (species, genera or any level of inclusiveness)."
and
"For the particular area of research that has to do with the making of
classifications it is certainly true that numerical phylogenetic methods
are by far the robust option to select hypotheses of groups, characters
and change."

Yes, I agree, in part.

I am interested, however, in evolutionary taxonomy, which maximizes
evolutionary information in classification (working with Linnaean
classification). Lineages and level of inclusiveness are okay but only
part of evolution. Note that you select the most robust of phylogenetic
hypotheses, not evolutionary hypotheses. E.g. if you compare support for
Ephemeraceae as a family apart from the Pottiaceae with lumping it,
there is no support when only phylogenetically informative traits are
used. Autapomorphies are ignored.

Suppose the Ephemeraceae occurred at the base of the Pottiaceae as a
sister group? It would be recognized as a separate family. Given there
are many genera in the Pottiaceae, the chance the Ephemeraceae would
differentiate at the base of the Pottiaceae rather than from a distal
clade is 1 divided by the number of Pottiaceae genera in the cladogram.
This is genuinely arbitrary, and the concepts of the evolution of this
family are affected (by deletion of the family description in literature
based on the classification) by an rigid enforcement of monophyly.

If you select hypotheses of "groups, characters and change" based only
on relative branching of lineages, then anagenetic, autapomorphic
information is missing from the classification. This may include
important evolutionary information such as a description of a family
which may be deleted from the literature if the family is lumped in an
influential (phylogenetic) classification. This definitely affects
biodiversity study, since degree of change is only reflected as relative
degree in phylogenetics, not absolute degree as in evolutionary
taxonomy.

Your fellow innocent,
R.

*****************************
Richard H. Zander
Voice: 314-577-0276
Missouri Botanical Garden
PO Box 299
St. Louis, MO 63166-0299 USA
richard.zander@mobot.org
Web sites: http://www.mobot.org/plantscience/resbot/
and http://www.mobot.org/plantscience/bfna/bfnamenu.htm
*****************************