Yesterday, following a haircut and a good bit of writing, plus our weekly team meeting with carry-out Kung Pao Chicken, I heard an interesting claim on Science Friday: natural selection no longer applies to humans in developed countries.
The biologist making the claim explained that the variety of human genetic characteristics no longer affects our ability to live long enough to reproduce, so what the heck.
He put it more extensively, but that is the main point. We may be growing less healthy, or destroying our planet, or losing the habit of critical thinking, but as long as most of us grown up and have offspring, it doesn’t matter. Once we’ve done that we are, from an evolutionary perspective, used up. If we go on to die from heart disease or diabetes or to fill our seas with suntan oil and packaging materials, it doesn’t really have any effect on the DNA of future generations.
Science magazine reports that evolution is still taking place among humans, and that we can actually see it in the genome. But it would still be possible to argue that the visible changes are influenced now by sexual selection rather than ye olde Survival of the Fittest.
Mental Floss also offers some examples of (relatively) recent evolutionary change among humans, including smaller brains. Intelligence, which has been a big advantage for humans, may no longer be that important. Or at least it may no longer be a big deal from the point of view of reproductive success.
Something interesting to think about.
Today I did errands and housework and baking and then went over to #1 daughter’s place, where #1 son and DIL and the children and the Good Ol’ Boy were enjoying the pool.
This evening I return to my knitting.