Farewell to Species - reticulation

[Richard Jensen]

On Mon, 14 Feb 2000, Thomas DiBenedetto wrote:

> T.S.:
> Thus, it is only logical that taxonomy itself cannot and should not be based
> on ancestor-descendant relationships already in the first take, rather
> ancestor-descendants relationships may be products that come out of good
> taxonomies.
> ------------------------
> I dont see systematics or taxonomy having much of anything to do with
> ancestor-descendant relationships. "Alpha" taxonomy is about identifying
> distinct, previously unrecognized terminal taxa (new species), or
> revistiting previous proposals of that type. Systematics is about
> discovering the sister-group relationships of taxa. Ancestor-descendant
> relationships seem to me to be outside of the purview of empirical science.
> But to your more general point that taxonomy should not be based on
> systematics, but rather vice versa, I disagree. How could one discover
> anything about phylogeny through the use of non-phylogenetic taxonomy?
>
> Tom DiBenedetto
> tdib at dccmc.org
>
I have to disagree.  Classifications based on overall similarity,
especially when the only appropriate species concept is a traditional
morphological (phenetic) or biological concept, can be very informative
with respect to possible phylogenetic relationships.  The user must
remember that these classifications are not intended to produce
monophyletic subsets, but they often do.  And, when one employs
Estabrook's suggestion of convex phenetics, one can often recognize clades
or grades that can help one understand the phylogenetic structure
of the group.

Besides, a phenetic classification is often to be preferred when it comes
to stability and information content.

Dick

Richard J. Jensen      |   E-MAIL: rjensen at saintmarys.edu
Dept. of Biology       |   TELEPHONE: 219-284-4674
Saint Mary's College   |   FAX: 219-284-4716
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