Re: Hierarchal vs Non-Hierarchal Interfaces to Biological Taxonomy

On Dec 22, 1:17 pm, Bob Badour <bbad..._at_pei.sympatico.ca> wrote:
> Larry Coon wrote:
> > Bob Badour wrote:
>
> >>Which common bird is it that has three cohorts A, B and C where A and B
> >>can interbreed, B and C can interbreed but A and C cannot? Is it the robin?
>
> > There's lots of species like that -- it's called a ring
> > species. I think it's the salamander where every subspecies
> > but two can interbreed.
>
> > An interesting question is when you have subspecies A, B & C,
> > where A & C cannot interbreed, and B goes extinct, do you now
> > have two distinct species?
>
> Which opens the floor to: "How many species did you have
> before B went extinct?"

These kinds of questions are always interesting. And they often lead me to the same conclusion, which is that the concept being discussed is a construct of the human mind, and not of the natural world. The very idea of "species" is an abstraction. A useful one, but an abstraction nonetheless.

Other things that are abstractions: the
number 3, the concept of being alive,
the gender partition with its two equivalence classes, male and female, the seasons,
etc. Most any idea with sharp edges to
it is an abstraction; the natural world
is much more fine grained. (I am tempted to say "analog" but when you get down to a low enough level, it looks digital again.)

Marshall Received on Fri Dec 22 2006 - 23:39:48 CET