(June 10, 2015 at 10:21 am)FatAndFaithless Wrote: Well..if they were different species they couldn't breed with each other.
Not true.
Members of different, but related species can and do often breed with each other. They often can even sometimes produce viable offsprings. But their offsprings are not fertile. When two individuals can breed and produce fertile offsprings, then they would be considered members of the same species.
But Even that is more clear cut in theory then in practice.
The degree to which two fertile individuals of different sex may successfully breed and produce fertile offsprings decreases as their genetic differences increases. But there is no abrupt cutoff. When two individuals are genetically very close, which all modern HSS are, then they can freely interbreed and produce fertile offsprings of both sexes. When they are more distant, often they can interbreed and produce offsprings, but either all offsprings from such a pairing is invariably of just one sex, or only offsprings of one sex is fertile.
There are hints from human genetics that any pairing between HSS and Neanderthals produced either only females offsprings, or only the female offsprings from such unions were fertile. Neanderthal genes that passed into the HSS gene pool seems to have passed only through female. If this was indeed the case, than it seems the interbreedability between HSS and Neanderthals were not complete. This argues against including Neanderthals in the homo sapient species.
