Inter spieces re-production does not happen...
And closely related spieces reproduction is ALWAYS sterile...
Same with some plants or animals.. mostly it can't happen at all period..
No response is sought for, asked for, or even desired..
Dead end conversations are SO boring.. I'd rather talk about democracy and how it sucks.. and how it ALWAYS produces socialism.. basically democracy is a prelude to socialism.. since socialism is a symptom of democracy.. and really thats what the forum is about anyways.. a FreeRepublic..
Humans trying figure out where they came from is like a Chimp seriously pondering a Rolex watch.. Whats goin through his mind ?.. That is where my mind goes with it.. What that Chimp is thinking has GOT to be WRONG... If he really cares at all.. Its all in my book...
Scratch-scratch...
HMmmm...
Should I have REALLY bought this from that e-mail place that offered me such a good deal????
Scratch-scratch-scratch...
Is this your definition of a species (failure of reproduction)? If so, it contradicts your comment: And closely related spieces reproduction is ALWAYS sterile...
Fertile mules do exist.
Note that your definition would imply and tigers are the same species.