There is nothing to distinguish true evolution from societal pressures here.
If they could demonstrate something physical, like earlier puberty while controlling for nutrition status, that would be a little more convincing.
From what I’ve read about pioneer America, the age at first childbirth was lower than it is now.
One last critique, and that is that these researchers were looking at an island; conclusions made about an isolated population cannot be extrapolated to the entire population. They are only pertinent to the isolated population.
Oh, and I do not question that humans are continuing to evolve, nor that we are shaping our evolution. Every time someone has a kid through medical interventions (e.g. “test tube baby” or fertility treatments), they are contributing to decreasing the fitness of the human race. Eventually, we could reach a point where medical intervention for reproduction becomes the norm rather than the exception. There are many other examples about how we are preserving traits not conducive to survival, but to point them out would make me seem heartless.
Great points, particularly the in vitro reproduction, but also c-sections, etc. There is always some sense that our tech makes life too easy or does it free up physical restraint to allow our brains to improve?
At the same time, as regards birth, much of the above is happening because motherhood is being delayed. In the case of the most liberal they are instead simply passing motherhood by childless. I’m curious to watch the trends as the religious have a major advantage in child bearing. What will be the sociological effects? Will America become balkanized as liberals die out or can government schooling indoctrinate enough children to keep liberalism alive?
“There are many other examples about how we are preserving traits not conducive to survival, but to point them out would make me seem heartless.”
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I will volunteer to be heartless in your place. Young people who are so stupid as to have actually voted for our current “president” are allowed to reproduce. Certainly this does not bode well for the future of humanity.