Thanks John, that was a great read!  Mayr's definition of species is one of
many useful concepts he originated.  "A species is a group of actually or
potentially interbreeding natural populations reproductively isolated from
other such populations."   Of course, the kicker is that "reproductively
isolated" part.  Thus the small green nerite, Smaragdia viridis, found in
the Caribbean and the Mediterranean could be separated into two species (of
course the literature is still fighting over subspecies status).  The two
populations are sufficiently visibly different to enable almost anyone to
separate them and the populations are reproductively isolated.  They may
have interbred at one time (maybe around the Miocene), but the veligers are
no longer able to make the transatlantic journey.  If one believes in
natural selection and speciation, then these two populations have been on
that track for quite some time.  The question is where/when do we draw the
line and say, "Okay, you are now two different species."

Perhaps Mayr's greatest contribution is that he sees this "grayness" to
biology and does not believe we can finitely quantify this science with
numbers.  Thus statistical analysis and cladograms are eminently useful
tools, but they are only tools, part of a larger equation that also relies
upon field and lab observation and research.  The numbers can "prove" a
close relationship between a clam and an echinoderm - but our eyes and
experience tell us this is patently ridiculous.  A cladogram does very well
at pointing out possible and probable ancestral relationships, but falls
short when used for classification of living species - even though it so
often looks like it does just that.  Similarly, a statistical analysis of
dimension, tooth count, weight, etc. between shells is an useful tool as
long as one never believes this is the final answer.  It can demonstrate the
bell curve of variation within a population but I believe will always fall
short of differentiating species.

All of the above is a layman's opinion and I am in way over my head, but
always enjoy a good argument.

Tom Eichhorst in New Mexico, USA

> -----Original Message-----
> From: Conchologists of America List [mailto:[log in to unmask]]On
> Behalf Of John Wolff
> Sent: Wednesday, July 07, 2004 7:20 AM
> To: [log in to unmask]
> Subject: Ernst Mayr
>
>
> July 5 was the 100th birthday of eminent biologist Ernst Mayr.
> He made major contributions to the concept of species.
> A summary of his accomplishments and an interview of this remarkable
> scientist done 5 years ago is available at
> http://www.skeptic.com/eskeptic07-05-04.html
>
> John
>
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