What is a species?

This must be an easy question, right? Don't we teach this to high school kids everyday? Not so fast.

First let's start with the definition of a species at this link The point to be made is that the definition of species is incredibly muddy, even now that we're basing federal laws with nasty penalties upon it.

One popular definition of species that has been used in other blogs is Ernst Mayr's definition, from the link above:

Mayr (1940) defined species as "groups of actually or potentially interbreeding natural populations which are reproductively isolated from other such groups." Dobzhansky (1950) defined species as "the largest and most inclusive ... reproductive community of sexual and cross-fertilizing individuals which share a common gene pool."

Hmm. This is convenient for those who would want to call a spotted owl distinctive enough to warrant Federal protection via the Endangered Species Act (ESA). (note-this is a PDF).

But it would also seem to tell us that Laplanders, Eskimos, Arabs, Nigerians, Maoris, Yanomamo and others are in fact distinct species, and that's about as unPC as you can get. We dare not suggest that there is even such a thing as races, much less different species of humans.

OK, we can dance around this by insisting that the populations be able to breed successfully with others and have fertile offspring. All of the above can and do interbreed when they can get at each other, so that pulls all of us humans back into the same species again.

But what about the spotted owls? Has anyone ever tried to breed them with other owl species? Are they just another example of one larger owl species that happens to live in a particular type of environment? If so, why do they merit protection?

What do the feds say? From the PDF above:

(6) The term ‘‘endangered species’’ means any species which is in danger of extinction throughout all or a significant portion of its range other than a species of the Class Insecta determined by the Secretary to constitute a pest whose protection under the provisions of this Act would present an overwhelming and overriding risk to man.

So it is no help.

Do we get to pick and choose definitions depending on whose ox is gored?

UPDATE: From the comments, the ESA definition of "species":

(16) The term ''species'' includes any subspecies of fish or wildlife or plants, and any distinct population segment of any species of vertebrate fish or wildlife which interbreeds when mature."

Thank you Mr. Logan. I guess that's why I'm not an attorney.

Count on the feds to muddy the waters further - now a species is a subspecies et al. OK, now what's a subspecies?