[JeffAtlanta]

The definition of a species is a population that, in nature, does not breed with another.

That is not actually true. The ability to interbreed is often used as in indication but is not a determining factor. Ring species and asexual organisms demonstrate that the ability to interbreed is not an acceptable criteria.

In reality, there really is no such thing a concrete line that defines a "species". Evolution predicts that the the concept of a species will be murky and, in fact, it is.

[bobdsmith]

I wouldn't say it predicted it but expected it.

[From many - one.]

That which cannot interbreed is a species.

Limited fertility represents not-yet-complete speciation.

[JohnnyM]

So scientists cant define what a species is, yet claim speciation occurs. Fascinating.

JM