If in the future, science makes it possible to use cloning to "create" Neanderthals which were isolated in their own environment, would the revived species of Neanderthals evolve back into Homo Sapiens millions of years later? Would the process of evolution yield a new species of "humans" with Neanderthal ancestry?

You ask an interesting question about the process of evolution. Neo-Darwinians typically argue that species evolve by natural selection on random mutations. At any particular time, there is more than one kind of random mutation that is of selective advantage, and it is contingent which one of these (if any) occurs. So evolutionary history has a certain randomness and unrepeatability. If we recreated Neandertals and did not interbreed with them, they might evolve into yet another (new) human subspecies.

Some biologists have argued that some mutations are directed--i.e. not random and in response to specific environmental challenges. To the degree that this is so (and that environmental challenges repeat themselves) evolution might repeat itself. But this is a controversial theory and is not generally thought to account for much mutation.

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