[Pharmboy]

Great point...and we already have information related to that. For example, it is one amino acid change in the genotype in (mainly) Africans that gives rise to the phenotype of the sickle cell, which increases resistance to malaria yet can--in the homozygous state--lead to a painful and life-shortening disease.

Now you might say this is not evolution or speciation, but think about this: if drug-resistant malaria suddenly became a worldwide problem, those with the sickle cell trait might be the only survivors. The environment would have acted on this genotype and 'selected' it for survival. And, if enough time goes by, this remnant human population might become a distinct species.

The more subtle neuro-cognitive connections may not be teased out in our lifetimes.

[reasonisfaith]

What about basic morphological changes like skull size and skull shape?

[squarebarb]

Very interesting, thank you.