jrg13 at psu.edu
Thu Jun 10 08:08:09 EDT 1999
When we wrote the Lepidoptera catalogue of Vermont we not
only included English names, but also some French names
(not as comprehensive in the time we had) which seemed
appropriate with Quebec next door. On top of that we often
included more than one common name out of necessity, and
often there was a widespread useage of separate common
names for adults and larvae.
Doug Yanega makes reference to the complexities of demarkation
between species and other taxonomic levels. In systematics there
are two principle philosophies. Species and other taxa are either
classes where membership depends of some defining character
(such as a unique character, interbreeding), or they may be considered
to be individuals where it is necessary to specify characterise
features that are localized with respect to space and time.
The former concept is essentialist in that it requires spatiotemporally
unrestricted essences that are true for all places and time (which is
kind of anti-evolutionary since essences can't evolve) and includes
phylogenetic species concepts and biological species concepts. Only
the species as individuals concept allows for evolution.
Given these two different perspectives, it is not necessarily true that
the application for molecular techniques will automatically solve
complex problems. Perhaps the problems will always be complex,
which might not be surprising if evolution is taking place, and the
process of differentiation involves more than an individual point in
space and time.
I am more sure than Doug about what a species is - it is a link in a chain
of differentiation. Perhaps that seems generalized, but that's how I look
at the process. What Doug refers to as species concepts are really
species definitions, and as definitions they are essentialist. As far
as I am aware, there are only two species concepts - classes and
individuals. Its possible that Aristotle was right, and thins exist as
expressions of an inner essence, but the problem of empirical
demonstration, combined with exclusion of evolution makes me lean to
Doug's final commens about it all coming down to context suggests that
he also leans towards species as phylogenetic individuals. The emphasis
on local particulars in space and time all point towards the diagnosis
(rather than definition) of a species.
I apologize if I have digressed somewhat into general systematics matters,
but they do provide context for the chronic and persistant problems of
taxonomic identification. And the views expressed here may not
conform to the majority.
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