I think I met that challenge with this post already.
For their divergence times within the last 10-50K years or so, I think the scale of differences we see between domesticated plants and animals, and their wild ancestors, are rather extreme. And they haven’t at all had another 4 million 950 thousands years to diverge further, and they’re already well on their way.
I could also again invoke the case of the selection of multicellularity from single-celled ancestors in laboratory evolution.
But we also had a thread on Bechly’s silly challenge here. There are many issues with Bechly’s framing of the challenge, such as the fact that he declares there’s “no conceivable reason” why we shouldn’t see a divergence of the sort of scale we see between fully aquatic whales and their terrestial ancestors happening all around us all the time.
Well how about the fact that evolution of that scale typically requires a radical change in lifestyle (switching to occupying a different niche), which generally don’t happen but following large mass extinctions where such niches open up where they were previously occupied? It’s extremely difficult to move into an already well-occupied niche full of highly adapted organisms and then start competing if you’re, well, 5 million years behind in the arms-race.
There’s also the issue of Bechly’s insistance that the interval is 5 milion years, when it could be as long as 20 million or even more.