[central_va]

More recent evidence, however, has demonstrated how at least some populations can suddenly differentiate in only a few generations.

Preposterous.

[WhiskeyX]

“Preposterous.”

See Wikipedia:

Argumentum ad lapidem (Latin: “to the stone”) is a logical fallacy that consists in dismissing a statement as absurd without giving proof of its absurdity.[1] The form of argument employed by such dismissals is the argumentum ad lapidem, or appeal to the stone.[2][3]

The cichlid fishes in East African lakes is one of a number of examples of rapid speciation. Lake Victoria was dry only a few thousand years ago, yet these fishes have developed into genetically related species in only those few thousand years.
Ad lapidem statements are fallacious because they fail to address the merits of the claim in dispute. Ad hominem arguments, which dispute the merits of a claim’s advocate rather than the merits of the claim itself, are fallacious for the same reason. The same applies to proof by assertion, where an unproved or disproved claim is asserted as true on no ground other than that of its truth having been asserted.