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See Bateman's principle [1]. In most species, variability in reproductive success is greater in males than in females. This is also true for humans (even today)
by gpt5 5y ago
See Bateman's principle [1]. In most species, variability in reproductive success is greater in males than in females. This is also true for humans (even today) [2], modern human may have twice as many female ancestors as male ancestors.
This is fairly intuitive result when you consider gestation time - imagine a scenario where there are more male than female in a given moment for a given species. At most each female got fertilized once, so the number of distinct male parents is less than or equal to the number of females. If there are more females than males, the you get the same situation (less distinct male parents). This result is simply because a male parent can fertilize multiple females quickly, while gestation period limit the females.
This dynamic has led to sexual selection mostly affecting the males of the species, which means that this is where the competition happens. The move from polygamy to monogamy in human culture has allowed more males to reproduce and reduced this effect (although it still exists, and is significant).
1. https://en.wikipedia.org/wiki/Bateman%27s_principle https://en.wikipedia.org/wiki/Bateman%27s_principle
2. https://en.wikipedia.org/wiki/Reproductive_success#Humans https://en.wikipedia.org/wiki/Reproductive_success#Humans
- riedel 5y agoCan we look at species like Betta fish (I believe here the males do the hatching) to confirm such hypotheses?
- HelloNurse 5y agoFor typical oviparous fish the cost and timing of reproduction is similar between males and females (dumping a large mass of sperm vs. dumping a large mass of eggs, then taking care of the children) and fancy reproductive organs are irrelevant technology.
- riedel 5y agoExactly, however, the parent post also tried to expand this to a more general concept of evolutionary pressure and competitive behavioural patterns as I understood. If that is true we can solve a lot of 'problems' in the world by simply having the men doing at least most of the child care for the first few month of a toddlers life to compensate for the for the month before.
- emerongi 5y agoInterestingly, there is this paragraph in the Wikipedia article: > Although Bateman's principle served as a cornerstone for the study of sexual selection for many decades, it has recently been subject to criticism. Attempts to reproduce Bateman's experiments in 2012 and 2013 were unable to support his conclusions. Some scientists have criticized Bateman's experimental and statistical methods, or pointed out conflicting evidence, while others have defended the veracity of the principle and cited evidence in support of it. Seems like a very convincing conjecture otherwise, though.
- assbuttbuttass 5y ago> modern human may have twice as many female ancestors as male ancestors. I'm having trouble to understand how this can be true. It seems like every human should have equal numbers of male and female ancestors, e.g. by induction on how many generations back you look.
- anthonypasq 5y agoeveryone has more single uncles than single aunts. Human history was not entirely monogamous, and a few number of men mated a larger number of women.
- contradistinct 5y agoA single man can be your ancestor in more than one slot on your family tree.
- thaumasiotes 5y agoYes, but this is pretty severely understated. Everyone in your family tree definitely will appear there many times over, except for very recent ancestors. Taking an average human generation time of 25 years, you would theoretically have 2^30 = roughly a billion ancestors 30 generations back, or 750 years ago. But the population of the Earth in 1300 was... maybe 400 million. (e.g. https://www.census.gov/data/tables/time-series/demo/international-programs/historical-est-worldpop.html https://www.census.gov/data/tables/time-series/demo/internat... for world population estimates) And your ancestors in 1300 aren't drawn from the entire population of the world; they're drawn from a tightly restricted subset of that. And if you think that's ridiculous, imagine how many ancestors you'd have thirty-one generations back!