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> when they are compatible enough to bone each other and said boning yields fertile offspring This was a definition of species for a long time. In recent years

> when they are compatible enough to bone each other and said boning yields fertile offspring This was a definition of species for a long time. In recent years some have advocated for changing it a lot, to the point that they should just start calling different dog breeds their own species. Or to go the other way, are dogs and wolves different species? Is it homo neanderthalensis and homo sapiens or homo sapiens neanderthalensis and homo sapiens sapiens? In my opinion, Denisovans and Neanderthals are both obviously types of Homo Sapiens and the argument they aren't is at this point mostly promoted by those desperately clinging to the now disproven out of africa hypothesis.

DFHippie 7y ago
> the now disproven out of africa hypothesis. What? When was it disproven? There's evidence of interbreeding outside of Africa with other species, in some sense of that word, which also originated in Africa, right? Maybe I missed something.
- wnoise 7y ago
  The strongest version of "Out of Africa" or "Recent African origin of modern humans" is "Modern man developed in Africa, and then spread throughout the world, essentially unchanged, completely eliminating other archaic hominids". Given known interbreeding with other hominids, this is clearly false, or at best incomplete to the point of being misleading. This is in contrast to a "Multiregional origin of modern humans", which still has "expanding from Africa" first, but far before modern man developed, followed by evolution and development everywhere without modern features coming from Africa "all at once". This too is clearly false and misleading. There were large migrations from Africa with large genetic distances from the native hominid populations, and the resulting mixture appears to be much closer to African than the native hominids. The modern synthesis is multiple waves of expansion out of Africa and significant gene flow making the tree look more like a river delta: lots of forking but also lots of merging, though not to the point of an undifferentiated sea either. The exact details are constantly being reevaluated as more genetic data is acquired. This is significantly different from the strong Out-of-Africa hypothesis, but claims there have weakened to include essentially this picture. The difference between the two point of views is a matter of scale at this point: how strong are the waves out of Africa, how much was displacement vs interbreeding, how much do genes flow in patterns besides out-from-Africa, how much is one giant expansion a reasonable approximation, etc.

DFHippie 7y ago

> the now disproven out of africa hypothesis. What? When was it disproven? There's evidence of interbreeding outside of Africa with other species, in some sense of that word, which also originated in Africa, right? Maybe I missed something.

wnoise 7y ago
The strongest version of "Out of Africa" or "Recent African origin of modern humans" is "Modern man developed in Africa, and then spread throughout the world, essentially unchanged, completely eliminating other archaic hominids". Given known interbreeding with other hominids, this is clearly false, or at best incomplete to the point of being misleading. This is in contrast to a "Multiregional origin of modern humans", which still has "expanding from Africa" first, but far before modern man developed, followed by evolution and development everywhere without modern features coming from Africa "all at once". This too is clearly false and misleading. There were large migrations from Africa with large genetic distances from the native hominid populations, and the resulting mixture appears to be much closer to African than the native hominids. The modern synthesis is multiple waves of expansion out of Africa and significant gene flow making the tree look more like a river delta: lots of forking but also lots of merging, though not to the point of an undifferentiated sea either. The exact details are constantly being reevaluated as more genetic data is acquired. This is significantly different from the strong Out-of-Africa hypothesis, but claims there have weakened to include essentially this picture. The difference between the two point of views is a matter of scale at this point: how strong are the waves out of Africa, how much was displacement vs interbreeding, how much do genes flow in patterns besides out-from-Africa, how much is one giant expansion a reasonable approximation, etc.