Real Species

[Richard Pyle]

Thank you, Pierre!  This is EXCATLY the line of thought I was fishing for.

> Individuals are rather well circumscribed biological systems in
> themselves.

Yes -- certainly moreso than populations or taxonomic clusterings.  But,
even individuals are dynamic entities (cycling from a pair of gametes,
through a succession of material turn-over, through entropy and
dissolution).  Subtly so in mega-fauna; less subtly so in colonial and other
more "ambiguous" individual organisms.  But this is another philosophical
discussion, probably not suited for this forum.

> This said, it is not because you have a clear criterion (or unambiguously
> combinable series of criteria) that species limits will not sometimes
> appear fuzzy in the real world (see other posts). This is "real" too: the
> easiness with which natural features will fit (or not well fit) into your
> conventional classification grid. Part of the explanation is the ongoing
> evolutionary process, and possibly "speciation" process, which is
> progressive in populations and biotas (see many other posts).

Yes!  Agreed on all points!

> Thus, OK with Richard's hint that species "boundaries are (artificially)
> defined by us as a means to allow more effective communication". And
> "effective communication" (hence relevant criteria) may change
> according to
> different questions at stake. Classification implements useful
> conventions (at best!).

Exactly!  Your ability to communicate in the English language is far
superior to my own! :-)

> Some will call "real species" the classes of individuals fitting
> unambiguously their classification criteria; they rather should be called
> "well discriminated species" according to these particular criteria.

Yes -- the critical issue here being "their classification criteria".  Thus,
species (or any other taxonomic or other aggregate unit -- including
subspecies, populations, etc.) are "defined", not "discovered".  But even
here we have a semantic thorn, because given a definition of "species", one
could argue that boundaries between those defined units are "discovered", by
way of acquiring information relevant to the definition.

> Example: suppose you have a population of elephants.
[etc....]

Great example --

> - other question: an extreme proposition for phylogenetic analysis is to
> use individuals as terminal taxa. Seems it should work. Certainly for
> clonally reproducing organisms. And likely for other ones too (you simply
> expect fuzziness in the "tokogenetic" apical zone of the tree... and some
> extra computing time!).

Just allow Moore's Law a few more iterations....or better yet, wait for
quantum computing to become a reality.

> Hence classifications and their corresponding classes are not
> "real or not real" (they exist from the moment we forge them),

To be fair, I believe the implied meaning of "real" in this context is that
they (taxonomic entities like "species") exist and are identifiable outside
the scope "artificial" (=created by humans) definitions of taxonomic units.
I.e., they are "discovered" in nature; rather than defined.

> they are "useful or not useful" in a specified context,

This is a critical point that usually gets forgotten in the various debates
(e.g., cladistic vs. eclectic applications of Linnaean nomenclature).

Aloha,
Rich

=======================================================
Richard L. Pyle, PhD
Ichthyology, Bishop Museum
1525 Bernice St., Honolulu, HI 96817
Ph: (808)848-4115, Fax: (808)847-8252
email: deepreef at bishopmuseum.org
http://www.bishopmuseum.org/bishop/HBS/pylerichard.html