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The heritability of fertility makes world population stabilization unlikely

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Re: The heritability of fertility makes world population stabilization unlikely

#82
post #18

Earlier quoted context omitted.

Same trait may have different effects in different environments. In stone age, bad eyesight might have been a severe evolutionary disadvantage. After we invented eyeglasses, bad eyesight has no effect on your survival or number of children. In a culture where large families were normal, perhaps genetic traits that push you towards having a large family were hidden by cultural aspects that made you have a large family…

Actually, wearing eyeglasses is sometimes perceived as unattractive, causing lower chances of offspring.

Or perceived as attractive, as ‘studied’ if you think of peacock feathers. Probably only to be studied in hindsight depending on evolutionary success...

Re: The heritability of fertility makes world population stabilization unlikely

#83
post #65

Earlier quoted context omitted.

Somewhat related, https://www.conservationmagazine.org/2013/09/tv-as-birth-con...

I'd dispute a lot of what is in that source. Their heat-maps of various characteristics are a correlation only, and a correlation among things which tend to go together (fertility rate, tv ownership (wealth), gdp per capita, and female literacy usually increase in tandem as part of a cultural shift). This does not necessarily mean they cause each other. Also, ought we really to be brainwashing people to live how we w…

All good points. While I think TV is perhaps too specific an example, my personal hypothesis is that availability of other forms of entertainment is a cause of declining birth rate. I’d say close to half of my married friend couples do not plan on having kids, and their main reasoning is usually that they like their social life, freedom to travel, ability get out in the weekends and generally do what they want. Also often they don’t seem too keen on loading themselves with additional responsibilities.

Re: The heritability of fertility makes world population stabilization unlikely

#84

If this is true, then how do they explain population stabilization in, e.g., Europe, and other developed areas? Why shouldn't what worked for Europe work for the rest of the world?

If an antibiotic doesn't wipe out its target, then its target's numbers will be devastated in the short-term, but in the long-term, its target will evolve immunity to the antibiotic and ultimately recover.

If you think about it, contraceptives are extremely similar to an antibiotic whose target is human beings. We're still living in the short-term when the antibiotic seems to be effective.

Re: The heritability of fertility makes world population stabilization unlikely

#85
post #70
post #49

Earlier quoted context omitted.

[flagged]

> You do not understand evolution Probably. But although it is almost tautological that fertility is heritable, it doesn't follow that the first world infertility trend will reverse. If whatever is causing first world infertility (1) actually profits from our infertility and (2) is some kind of evolving entity itself, we could find ourselves in an evolutionary arms race, and lose.

An insightful point. The tacit assumption here is that your "whatever" is some sort of meme, yes? But memes are also strongly heritable. So far, in all of human history, memes which promote celibacy and childlessness have a tendency to die out.

Re: The heritability of fertility makes world population stabilization unlikely

#86

Earlier quoted context omitted.

Sorry, I didn't make the best choice of words. With "stabilized" I really meant "stopped growing". And indeed, in practice this has resulted into shrinking, not a steady state.

Fertility rates declining for several generations is not stabilization. It’s a bump in the road while humanity evolves resistance to whatever it is about modernity that causes us to have fewer children.

I don't think humans are every going to evolve past being a K-selected species.

Re: The heritability of fertility makes world population stabilization unlikely

#87
post #77
post #52

Earlier quoted context omitted.

What you should understand is: most geneticists wouldn't have had the balls to write this even though it's obvious to them. Someone did have the courage to write it. Now wrap your head around what they wrote.

It's not "obvious" at all and I've never heard anyone in the community express such sentiments, even in more informal settings. I don't even know what "courage" you're referring to. The courage to be associated to a journal with an IF < 4, maybe?

This obsession with journal impact factor is toxic in academia. It's what allows parasitic publishing companies to continue to extract rents despite contributing nothing to science for decades. The majority of papers are envelope-pushers, churned out in enormous numbers because of "publish or perish". Academics who need CV bullet-points are going to churn out quick papers that go with the status-quo, with bibliographies filled with papers that do likewise. So of course journals that push the status-quo are going to have high impact factors. Back when surgeons were laughing at the crackpot telling them to wash their hands, a paper on the unnecessity of hand-washing would be well-cited.

Re: The heritability of fertility makes world population stabilization unlikely

#88

All of my grandparents come from big families. My grandmother on my father's side comes from a family of 12 children. Yet my grandmother only had 4 children and my father only 2, and now I only have 1. This is an anecdote, but I don't think heritabiliy has anything to do with it. Large families simply happen due to poverty. When poor, you want more children because there's strength in numbers. Plus the women are stay…

[deleted]

Re: The heritability of fertility makes world population stabilization unlikely

#89
post #73

Earlier quoted context omitted.

Though I’m sure the Mormons would cop to traditionalism calling a religion where the median man spent two years of his life in a foreign country insular is slightly odd, considering most Americans never leave their own country. Even aside from that cosmopolitanism Mormons have been state governors and been contenders for the presidency. Insular they are not.

Insular was probably the wrong term to use, culturally rigid or conservative might be better. The point is they maintain a high fidelity to the cultural and behavioural patterns of their group. One of which is to eschew birth control and purposefully create large families.

They're commanded to "multiply and replenish the Earth."

Re: The heritability of fertility makes world population stabilization unlikely

#90
post #38
post #28

Earlier quoted context omitted.

> It’s at above 99% homozygotes. Meanin 99% of people who have this allele (trait) have two set of the corresponding gene/genes. Okay, but is lactose tolerance a dominant allele?

Yes, lactose tolerance means you have functioning enzyme. That makes it a dominant allele.

That's not how it works.

https://en.wikipedia.org/wiki/Dominance_(genetics)

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