In ten generations it's still pretty much to the average, and in 100, or 1000 generations, it's the same old same old.
Even most of our genes are not terribly different than those of our most ancient spongoid ancestors, or even bacteria!
The tools in the DNA that put together a liver, for example, are pretty much the same in every species with a liver.
So, what makes the difference?
The big boys in the new field of epigenetics say it's the extra copies, the sequence and the blanks, and the bypasses (many due to methylation) that make the difference ~ and that's a pretty complex piece of work ~ and neither Darwinian nor any other view of evolution and survival of the fittest can do more than say 'see there, it works' ~ how it works has yet to be determined.
The writer's thesis is that easy eats (agriculture) allow the less fit to survive.
presumably taking their food away will make them smarter ~ (snork/s)
Not really a ‘new’ field, but becoming much more of a focus now that it has become apparent that sequencing the genome wasn't the holy grail some had hoped. I've recently seen genetically identical twins who, as adults, are not the same height. Clearly ‘nuture’, including likely epigenetic modifications (such as the methylation you mention), plays a big role.
Having said that, the fact that we don't feed people to the lions in this century isn't because our DNA changed - or our methylation patterns are different. It's because humanity learned lessons that were passed on from generation to generation. If we stop passing on that which we've learned, those lessons can be lost.
No, it’s not epigenetics that makes the difference intellectually. Nor is it a lack of sufficiently rigorous natural selection. It is not biological at all. My assumption is innate intelligence has not changed since the advent of civilization. What makes groups smarter or stupider since then is learning, or a lack thereof.
Evolutionary science is really bad at history, economics, anthropology, and sociology, though decent at psychology. A perfect example is the povetyy of sociobiology. It lacks the equipment to understand experience, ir the world of “nurture.” Though it does have a few things to say about biological changes after the advent of of the organism, it is largely helpless in the face of culture.
Because its disciplined line can only in a robust manner explain how wewe’ve been generally for 65,000 years or so. It cannot explain at all, for instance, baseball or Beethoven except in very, very extremely general terms.
“the less fit to survive”
That is a contradiction. Fitness is defined as what us fit fir suurvival. If something survives it is by definition fit.
What you or they mean is the less intelligent survive. But that is simply not true. Average human intelligence, so far as we know, has stayed about the same since there have been humans. What’s happened, if anything, is that already born humans have been miseducated.