Seems to carry a hint of Lamarkian Evolution.
Seems to carry a hint of Lamarkian Evolution.
Not at all, although I can see how it could be misread that way.
He's not saying that softer foods *caused* the genetic changes, he's saying that in an "environment" of softer foods, mankind no longer needed such long, strong jaws, and selection was then free to make the beneficial trade-off of larger craniums (with the resulting smaller faces/jaws).
>>Seems to carry a hint of Lamarkian Evolution.
Not necessarily. The stresses put on the body can alter its devlopment. For example, someone who does a lot of weightlifting or other strenuous exercise during puberty will tend to devlop a heavier frame and larger build in adulthood. The genotype is unchanged, but the expression of the genotype can be altered by the environment.
Yeah, a lot of articles about evolution are sloppy that way and seem to suggest that the environment causes mutations. Mutations happen at random. They are retained because they are either beneficial or perhaps simply not harmful. While a smaller face might have become less harmful in an agricultural setting, that doesn't really explain why it would be better than the bigger face, which is what you need for replacement -- the one has to be superior to the other.
I think there might be a better explanation, though. I've heard it argued that human beings retain a lot more juvenile traits into adulthood than apes do, much as domestic animals carry more juvenile traits into adulthood. Further, part of what differentiates dog breeds, in both look and temperment, is determined by what parts of their physical or mental development is stunted. It's entirely possible that human development has become more stunted and that we've retained more juvenile traits into adulthood because those traits make us smarter or, like domestic animals, more sociable in larger settlements. Perhaps it could ultimately explain the Baby Boomer desire to never grow up.