8k years ago, 17 women reproduced for every 1 man
ncbi.nlm.nih.gov
ncbi.nlm.nih.gov
Saying that the development of society caused more sexual competition among men isn’t crazy. This study basically uses Y-chromosomal tracing to support that point.
[1]: https://en.wikipedia.org/wiki/Timeline_of_prehistory#cite_no...
https://www.ncbi.nlm.nih.gov/core/lw/2.0/html/tileshop_pmc/t...
Showing total # of male ancestors (left) and female (right)
I guess writing, agriculture, and fixed settlements allowed for dominance on a far greater scale. There's a natural limit to how much power you can project without technology.
I know it's poo poo'd in academic circles but if there was a great flood that destroyed most of human civilization that would also describe why this occurred.
Do floods kill significantly more men than women?
How much area would need to be flooded to affect most of human civilization 8-10k years ago? By that point we were spread out throughout the entire planet (except what, Polynesia and New Zealand?)
Seems to boil down to "the high status, high power males got all the women" which is unsurprising.
From the body: "However, the Y chromosome plot suggested a reduction at around 8–4 kya (Supplemental Fig. S4B; Supplemental Table S4) when the female Ne is up to 17-fold higher than the male Ne (Supplemental Fig. S5)."
Indeed, the title does not match the title of the paper, but hopefully makes it more approachable.
this sounds like a bias looking for data to suit it
birth rates generally decline as countries become more developed, there are numerous suspected causes (not related to monogamy)... generally the rule of thumb is... as education and income go up, birth rates decline: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4255510/
In the extreme, if a population stops reproducing, sexual selection doesn't occur (genetically) even if all sort of interesting sociological phenomena occur.
People may call this unnatural, but I wonder if other animals have similar behaviors that limit reproduction.
Experimental studies have shown that signals of high density (e.g., playing squirrel calls on loudspeakers) reduce reproduction even when density is not actually high. I would love to test the hypothesis that Instagram exposure of rural populations reduces reproduction independent of education and actual population density.
test the hypothesis on student debt and housing costs.
At least in my community, many of the men having kids with multiple women get married, have a kid, then divorce, remarry and have another kid. And even that is extremely rare compared to the men and women that only have children with a single partner.
My guess is that the number of babies born out of wedlock is much, much lower than ever before. Probably due to contraception, child support, abortion and DNA testing.
How would the falling popularity of monogamy cause this?
I assume they mean "coalescent Bayesian skyline plots".
Why invent a new name for something which already has a more informative name?
I have great difficulty imagining a culture which could socially sustain an N_e of 1:17 (male to female). Just do a few sample calculations. The priviledged males would be massacred.
A few things could explain it: (1) large scale male infanticide or male child castration (2) A disease which kills mainly male children.
Both of these alternatives suffer from one of the same problems as their proposal: How would the cause (whatever it was) spread so relatively quickly among distantly seperated populations ?
I think it far more likely they have made mistakes somewhere.
And I have a guess (though unsupported) that every civilization's mythology would tell similar stories of this event if it really were occurring globally.
A long, long time ago, in an universe so far away...
Those people don't know what happened yesterday, but they know for sure what happened 8k years ago.
Poor people who lack resources have more children.
I take it you haven't drafted a will, and don't plan to?
Nor do I see a major moral distinction between, say, setting off a nuclear bomb timed to explode one microsecond after your death, versus one microsecond before it.
Just like Fred.
The chance of a billionaire having a son is 65%. https://www.bbc.com/future/article/20161014-why-billionaires...
For the latter part, I'd argue along the lines of the selfish genes (Dawkins): Not an organism wants to reproduce but rather the individual genes. They use the body as a vehicle for that. So it can still make sense for an individual to not reproduce and increase the chances of the same genes to be passed on (e.g., when an uncle without kids supports the kids of his siblings).
An acknowledged offspring. How many unknown kids do they father with mistresses? How many pregnancies get terminated? More darkly, how many wives of millionaires terminate pregnancies before 12 weeks when the fetus is female, but not male?
Billionaires lead very different lives than millionaires
For example, imagine just for argument that the probability of the offspring being male or female is proportional to the number of sperm that carry either X or Y chromosomes. And imagine that this ratio is controlled by a gene, and that initially, the gene is such that across the whole population, 17 sperm carry an X chromosome for each that carries a Y chromosome. In this population, any male who has a mutation in this gene resulting in them producing a closer-to-equal number of X and Y sperm will have a reproductive fitness advantage, because they will have more male children amidst a majority-female population. Those mutations will therefore spread until the advantage disappears.
In order for 17-to-1 female:male ratio to be stable, you'd basically need to have a period of thousands of years in which, for whatever reason, 16/17ths of women do not reproduce. That's the exact opposite of the condition described in this article.
Being upper class and lower class apparently doesn't have significant biological indicator to affect strategies such as these.
The poorest among our society are still mostly drawing in the same amount of calories, and feel happiness and sadness, age mostly in the same way.
There are no indications that billionaires are significantly happier/healthier than us - in fact these indicators are mostly tangential with wealth past a certain point.
maybe post-Industrialization, but a whole lotta people died of famine and disease before then, and the ones getting hit hard were the poorest.
Remember that (mitochondria and Y-chromosomes aside) it's not the case that sons inherit their genes from their fathers and daughters from their mothers. The children of an upper-class father and a lower-class mother will have half of their genes from each parent regardless of sex or class.
But I'm pretty sure evolution still wants heaps of genetically diverse males to come out and compete in the reproductive lottery. Even if only a few of them win, they're the .. well, winners, genetically speaking.
With fewer participating at an existence level, you'd have would-be losers succeeding for lack of competition.