Re: Hierarchal vs Non-Hierarchal Interfaces to Biological Taxonomy
Date: Sun, 24 Dec 2006 09:12:04 -0800
Message-ID: <458EB4E4.115C_at_cox.net>
Bob Badour wrote:
> Do you think donkeys and horses are the same species? Or does the
> reasoning that leads to "one" above lead to "two" for them?
In general, we differentiate species on the basis of:
1) Typology (conforming to a set of fixed characteristics);
2) Morphometry (essentially the way they look. IE, some
organisms can look very similar without being closely
related);
3) Sexual isolation (this gets to your question about
hybrids like mules. In most cases, the hybrids are
sterile, so they do not challenge this criterion).
4) Phylogeny -- members of a species have a common
ancestor.
> What is the definition of ancestor that excludes them?
There is no phylogenic relationship, for one.
> Agreed. Are you familiar with Aubrey de Grey's theory of mitochondrial
> aging?
No. (Admittedly this isn't my field, so my knowledge only goes so far -- and I had to look up the part above about species). I'm a computer scientist who happens to have an interest in all science. It sounds like Paul is much better qualified to discuss these topics than I.)
Larry Coon
University of California
Received on Sun Dec 24 2006 - 18:12:04 CET