Fwd: Nomenclature and classification

[Philip Cantino]

Gurcharan Singh wrote:


>   I think a distinction has to be made between whether we are dealing
>with
>biological entities (species and infraspecific taxa) or artifacts
>(supraspecific taxa). We won't discover a supraspecific taxon (but
>rather
>create one to ease our process of classification). If we discover a
>biological
>entity (It would a matter of taxonomic judgement whether to consider it
>a
>species, subspecies, variety or even a form if you like it), its
>position in
>different classification systems would remain unaltered,  except when
>you make
>a drastic change of shifting it to a different genus. The names of
>different
>supraspecif taxa are, however, clearly linked with the classification
>scheme
>you are following.


This distinction between species and supraspecific taxa does not
apply to phylogenetic nomenclature.  Clades (the only supraspecific
taxa in phylogenetic nomenclature) are not human constructs.  A clade
is a biological entity--a complete product of evolution that exists
whether or not we discover it and whose existence is hypothesized
based on evidence.  One of the things that I find philosophically
appealing about phylogenetic nomenclature is that the entities being
named have an objective reality (though they are not necessarily
easy to discover), whereas I would agree with Dr. Singh that many
supraspecific taxa that have traditionally been recognized in
Linnaean classification are human constructs.

Phil



Philip D. Cantino
Professor and Chair
Department of Environmental and Plant Biology
Ohio University
Athens, OH 45701-2979
U.S.A.

Phone: (740) 593-1128; 593-1126
Fax: (740) 593-1130
e-mail: cantino at ohio.edu