species and genus

[John Grehan]

  It makes little biological difference if a taxon is a genus or
>subgenus, family or subfamily, but a great deal of difference if a taxon is
>a species or subspecies.  A species is an entity, but a genus is a concept.
>
>Bill Shear

While it may make little "biological difference" I am uncertain about a
species
being distinguished from a higher taxon by virtue of being an entity as
opposed
to a concept. The species is a concept also. As an entity I have never seen
a species as such any more than I have seen a genus. Further, I can map
the distributions of genera or any other taxa and get empirical results (such
as predictions of new facts about earth history), so I am mapping something
more than just a concept.

John Grehan