RE: Has 'one species' idea been put to bed?
January 4, 2012 at 2:42 am
(This post was last modified: January 4, 2012 at 2:46 am by Anomalocaris.)
A working definition of species is a population which is not prevented from freely interbreeding and producing fertile offsprings by genetically driven factors, including genetically driven behavior.
Thus Eskimos, Europeans and African pigmies all belong to the same species because if if mixed together, nothing genetic would dominate and prevent them from freely interbreeding and producing fertile offsprings, racists be damned.
Conversely, if two populations can mix together and interbreed, but not completely freely. For example, if only offspring of one particular sex is fertile and the other not, then the two population do not belong to the same species. Similarly, when two populations can produce fertile offsprings of either or both sexes if forceably mixed and made to interbred by, for example, artificial insemination, but they can never, or very seldom, interbred in nature due to genetic factors, like different breeding seasons, then despite reproductive compatibility those two population do not belong to the same species because of genetically driven behavioral incompatibility.
At current, it is not clear to me whether evidence shows human and Neanderthals can truly freely interbreed, or if the interbreeding is limited by genetic factors. So it is too early to tell, despite appearent presence of neanderthal gene in humans, whether neatherthal and HSS truly belong unquestionable to the same species.
Thus Eskimos, Europeans and African pigmies all belong to the same species because if if mixed together, nothing genetic would dominate and prevent them from freely interbreeding and producing fertile offsprings, racists be damned.
Conversely, if two populations can mix together and interbreed, but not completely freely. For example, if only offspring of one particular sex is fertile and the other not, then the two population do not belong to the same species. Similarly, when two populations can produce fertile offsprings of either or both sexes if forceably mixed and made to interbred by, for example, artificial insemination, but they can never, or very seldom, interbred in nature due to genetic factors, like different breeding seasons, then despite reproductive compatibility those two population do not belong to the same species because of genetically driven behavioral incompatibility.
At current, it is not clear to me whether evidence shows human and Neanderthals can truly freely interbreed, or if the interbreeding is limited by genetic factors. So it is too early to tell, despite appearent presence of neanderthal gene in humans, whether neatherthal and HSS truly belong unquestionable to the same species.
