Fwd: Re: concept 4

[warrena at bcc.orst.edu]

Thanks Michael!

It is nice to see a concrete example cited!  Note,
however, that because of the wording of the definition
("assuming of course that they did or could interbreed
where populations come into contact"), it is only
applicable under the Biological Species Concept (which
is not surprising since the BSC was also coined in the
1950's).  While I am sure this subspecies definition is
still used today by working taxonomists, I have not
seen a paper objectively justifying why 75% should be
the magic number- that magic cutoff point (this seems
subjective to me); why not 70% or 80%?.

I admit my views on subspecies are just that, my views
(although they are justified well by the literature).
It is true and obvious that subspecies will not go away-
 check out Science Magazine where an issue or two ago
some ornithologists proposed "megasubspecies"
and "megasubgenera".  I wrote my posting to point out
that the subspecies category is the least well defined
and perhaps most widely disputed taxonomic category.
More so than species, any two authors talking about
subspecies are usually talking about totally different
things.  I just think subspecies are more defendable if
people who propose them can define them in objective
terms, that's all.

Andy Warren


Quoting Michael Gochfeld <gochfeld at eohsi.rutgers.edu>:

>
>
> warrena at bcc.orst.edu wrote:
>
> > Quoting Ron Gatrelle
> <gatrelle at tils-ttr.org>:
> >
> > Thanks Ron!  All I can say is that I would
> not
> > know "biological truth," "functional truth,"
> "absolute
> > truth," or the "actual pattern of evolution"
> if it came
> > up to me and hit me in the face :)
> >
> > I have yet to see an objective definition of
> a
> > subspecies anywhere in print.  Please direct
> me to the
> > source if anyone knows of such a definition.
> >
> > Andy
>
> Many many years ago, Dean Amadon of the AMNH
> published the 75% rule for
> avian subspecies, indicating that
> if measurements (beak or wing or tail or leg or
> toe) of two populations
> showed 75% non-overlap, it was fair to designate
> the two as subspecies
> (assuming of course that they did or could
> interbreed where the
> populations came into contact.  Part of this
> theme is that much of the
> variation in bird species (particularly in the
> eastern United States was
> clinal (continuous) and that there were although
> New England and Florida
> birds might differ in size (or in pigmentation)
> there was no breakpoint
> (or stepped cline) that would allow designation
> of subspecies.
>
> This may not apply to butterflies, but it is an
> "objective definition of
> a subspecies" in print (AMNH Bulletin circa
> 1950s).
>
> Mike Gochfeld
>

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