Re: Hierarchal vs Non-Hierarchal Interfaces to Biological Taxonomy
Date: Fri, 22 Dec 2006 16:19:00 -0800
Message-ID: <458C75F4.5404_at_cox.net>
Bob Badour wrote:
Answering several distinct posts at once here...
> >>Which opens the floor to: "How many species did you have
> >>before B went extinct?"
One.
> > 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.
Correct.
> Here's an even better one: Suppose a retrovirus comes along that conveys
> some fitness advantage so that it becomes ubiquitous among a species:
> ducks for instance. Suppose as well that the virus crosses over from the
> domesticated duck population into pigs and humans where it too becomes
> ubiquitous.
>
> At that point, humans, ducks and pigs all share a unique recent
> ancestor. Where does that put us in the taxonomy with ducks and pigs?
Your "at that point, humans, ducks and pigs all share a unique recent ancestor" is an incorrect premise. A percentage of the human genome (I want to say 8%, but I don't remember for sure) came from outside organisms like virii, but that doesn't make them our ancestors.
Larry Coon
University of California
Received on Sat Dec 23 2006 - 01:19:00 CET