& BRIEFLY NOTED: For 2021-12-31 Fr: First: All of us (men) have y-chromosomes that are those of Y-Chromosome Adam back roughly some 200,000 years ago, with whatever mutations of that have occurred since..... The amount of branching at each calculated date in the past tells us what the effective population size (of men) was then, for each y-sperm that fertilizes an egg is another chance for mutations to occur.... All of us have mitochondria that are those of Mitochondrial Eve.... With the invention of agriculture, it looks as though things go bonkers. Mitochondrial lines continue to multiply at a furious pace as mutations happen. Y-chromosome lines… sharply slow down in their multiplication, as the men’s side of the effective population crashes. It looks as though at the trough, 5 thousand years ago, the men who have living descendants today only 1/20 of the fraction of women alive then who have living descendants today...
I'm pretty confident that the polygyny explanation is correct, but I'm wondering if there's another possible explanation. We know that the transition to farming led to much poorer health for the farmers, including substantial decreases in average height. Is it possible that the now-smaller women had both poor nutrition during pregnancy and a much greater likelihood of dying in childbirth? This would reduce the number of successful live births per each female and increase the number of women necessary to produce the same number of male children who survived to reproduce.
To make this clear, suppose each farming woman gave birth to just one male child who survived to reproduce, compared to a hunter-gatherer woman who produced 3 such male children. That would account for the "extra" women in 5000 years b.p. compared to 10,000 years b.p.
This analysis dovetails nicely with this excellent post by Dr. Alice Evans, titled "10,000 Years of Patriarchy": https://www.draliceevans.com/post/ten-thousand-years-of-patriarchy-1
The connections between agricultural practices and the rise of patriarchy are nicely elucidated.
I'm pretty confident that the polygyny explanation is correct, but I'm wondering if there's another possible explanation. We know that the transition to farming led to much poorer health for the farmers, including substantial decreases in average height. Is it possible that the now-smaller women had both poor nutrition during pregnancy and a much greater likelihood of dying in childbirth? This would reduce the number of successful live births per each female and increase the number of women necessary to produce the same number of male children who survived to reproduce.
To make this clear, suppose each farming woman gave birth to just one male child who survived to reproduce, compared to a hunter-gatherer woman who produced 3 such male children. That would account for the "extra" women in 5000 years b.p. compared to 10,000 years b.p.