[abricq]

On a slightly related topic, I remember to have seen an exposition where an artist was asked to represents what a human who has naturally evolved to survive a car crash might look like. And it has a cool / terrifying website: http://www.meetgraham.com.au/view-graham

Quite fascinating topic to wonder about: how long will it take for the modern era to genetically change us ?

[BurningFrog]

Men will evolve to manage sperm banks and fertility clinics.

[MrLeap]

After the high profile grossness with those, you'd think every person using those services would do a paternity test just in case.

[highcountess]

To answer your question, it already has changed us in many ways. You are not the only one who does not realize this though. It is in fact the prevailing position.

We have diseases and genetic defects, among other impacts through modern behaviors and environments/toxins, which are also retained in the genetic mutational load. We even have a whole lot of energy and human activity working to counter evolutionary pressures and assure those accumulated mutational loads remain in the genetic code.

[amanaplanacanal]

Fitness depends on the specific environment the creature is in. Environmental fitness for the ancestral environment when all humans were hunter-gatherers is not necessarily the same as fitness for living in an industrial society. Evolutionary pressure still works just fine.

[spacebanana7]

Humans are beyond evolution. There's no meaningful selection pressure in our environment that kills people before reproductive age, so there's no reward for adaptations.

[svara]

Totally wrong, killing humans is not required for evolution.

Ignoring genetic drift and taking into account only natural selection, all that's needed is differences in fitness, i.e. differences in how much an individual contributes to the gene pool of future generations.

[mattigames]

People is taking the parent comment literally but that was very clearly not the intent, obviously human evolution in the stricly technical biological sense its still happening (e.g. genetic diversity) but is by far currently molded by changes done by humanity itself (e.g. industralization, tech) not by factors outside their control as it happens with every other animal on earth, and as it adapts to the environment of its own creation it also loses the traits that favor surviving outside of such an environemnt (e.g. in case of disaster and we lose some of that environment, like a nuclear holocaust)

There are ways we could avoid losing most of that survivability but of course they are wildly unpopular such as actively discourage people with terrible inheritable diseases to procreate (e.g. ALS, Lupus), favor reproduction of people with both higher intelligence and physical skills (e.g. goverment subsidies for their parents, tied to their children grades and general well being)

[hammock]

This. “Natural selection” refers to selection and survivability of traits, not of individuals. Evolution is how that selection process then manifests itself over time in a population.

[Galaxeblaffer]

can't remember where i read this, but significant and big leaps in evolution seem to often happen in times of crisis when the environment forces it. that's not to say that evolution doesn't happen all the time with little pressure it's just very slow when things are more stable. by extension big leaps in evolution can really be down to a low number of individuals. read an article about a genetic study claiming the human population was down to a few thousand individuals around 90k years ago.

[quesera]

Punctuated equilibrium.

Not sure if he's the originator, but I'm pretty sure I learned about it in a Richard Dawkins book.

[pfannkuchen]

Crisis presumably doesn’t affect the rate of mutation, so is the mechanism here just that there is a tight filter that from the perspective of future animals made the species more like themselves, because by definition the future animals have passed the filter?

Like the traits must have already been present in some lower frequency pre crisis, and the crisis distills the traits which are selected for by the crisis.

So probably less evolution moves faster during crisis and more that there is an interesting survivorship bias related to crisis when analyzing the change of a species over time.

[thaumasiotes]

Well...

Evolution is not primarily driven by the mutation rate. It's primarily driven by differential success of already-existing genetic variation. Over the very, very long term, you need mutation to be the source of that genetic variation, but over the short term mutation is mostly just harmful, and this:

> Like the traits must have already been present in some lower frequency pre crisis, and the crisis distills the traits which are selected for by the crisis.

is correct.

> So probably less evolution moves faster during crisis and more that there is an interesting survivorship bias related to crisis when analyzing the change of a species over time.

This is conceptually wrong; in this context "survivorship bias" bears a technical name you've probably heard of, "natural selection". A stronger survivorship bias means faster evolution.

[hammock]

That all seems logical. What is the connection to the previous point?

[Galaxeblaffer]

I think i misread your comment a bit. i thought you where making the point that evolution was only about mutations on a large scale and that individuals doesn't really matter. But what you are writing is true even though populations can become very small where these small populations that survive have sometimes been selected for because of traits that mutated in a larger population earlier. Sometimes though it's just the lucky ones that weren't in the wrong spot at the wrong time.

[swalling]

Dead wrong. https://en.wikipedia.org/wiki/Recent_human_evolution

[red-iron-pine]

no one is having babies mon ami. birth rates are declining.

it's not about killing people before reproductive age, it's about absolute numbers of offspring born. dying before reproducing ensures that number stays 0, but you can still hit sexual maturity and not reproduce.

plus there is a fertility window -- after 50 most humans, male or female, ain't having kids (a handful of rockstar types whelping babies at 80 notwithstanding).

there is a TON of meaningful pressure in our environment, like the inability to have a living wage reducing how many Gen Z's are marrying and having kids.

[thaumasiotes]

> it's not about killing people before reproductive age, it's about absolute numbers of offspring born.

Technically, it's about averaging offspring (weighted by your genetic contribution to them) across all of time. If you have 30 children, and all of them starve to death before reproducing, you've reproduced less than your neighbor with the one child and one grandchild.

But that's impossible to calculate, so mostly we just have to work with number of children. This detail, though, is something you might want to keep in mind when looking at reports of "effective population" in the past. Any actual population in the far past who end up being wiped out in the middle past are excluded from the "effective population" that we calculate.

https://en.wikipedia.org/wiki/Effective_population_size

[steve_adams_86]

This simply isn't how evolution works. There's no way to be "beyond" it. It's an inevitable facet of populations of living organisms.

If a population used genetic engineering to collectively ensure their genetics didn't change, no mutations, no other populations involved, then... I guess? Otherwise, there is this staggering multitude of influences.

Living longer and reproducing longer is a huge weight on the scales of evolution. Why does anyone need to die early for it to work?

[JumpCrisscross]

> Humans are beyond evolution

Empirically false [1]. The median artery is a poignant example from the industrial era [2].

[1] https://en.wikipedia.org/wiki/Recent_human_evolution#Early_M...

[2] https://en.wikipedia.org/wiki/Median_artery

[s1artibartfast]

Interesting article on the median artery given that there is no proposed advantage to the phenotype that is increasing in representation.

My understanding is that evolution is specifically directional change in response to a pressure, not random drift or coincidence.

Is it accurate to say a trait evolved if the change in prevalence is entirely incidental and tied to a second Factor?

Is it accurate to say a trait evolved if the change is a regression to the mean in the absence of pressure?

I went looking for papers on why the median artery might be selected for, and one hypothesized that it may be grouped with, fetal deformities, such as spina bifida, which are increasing not because they are advantageous, but because adverse selection pressures are diminished.

Another hypothesis is that the variation in median artery is not reflective of a change in genome, but change in environmentally triggered gene expression associated with maternal health.

[JumpCrisscross]

> one hypothesized that it may be grouped with, fetal deformities, such as spina bifida, which are increasing not because they are advantageous, but because adverse selection pressures are diminished

Nobody seems to have studied the effects of a persistent median artery on dexterity (important amidst increasing literacy and now phone/computer use) or forearm circumference (looks hot).

[s1artibartfast]

Dexterity would be an interesting one. Whatever it is (direct or associated) must be a strong force to triple the prevalence in 150 years or so. Thats like 15% growth each 20-year generation, which would be a huge difference in reproductive success. I think this puts a pretty strong indicator that it's not a genome shift but something else

[foldingmoney]

>My understanding is that evolution is specifically directional change in response to a pressure, not random drift or coincidence.

Evolution just means change, and it includes genetic drift. In common parlance, 'evolution' generally implies improvement, but that's not the technical definition.

[s1artibartfast]

Thanks, I was conflating it with natural selection.

[ninetyninenine]

There is incredibly high sexual selection. Birth control is effecting this.

Note that sexual selection selects for health, wealth and reputation. Women are doing most of the selection here.

[SamBam]

Evidence?

Take just the easiest to measure of those factors, wealth. Per your hypothesis, wealthier men should have more babies. Do you have any evidence that wealthier men have more babies?

In fact, it's quite the opposite. There is a strong inverse correlation between wealth and number of babies. Both globally [1] and in the US [2]. There is some data that you can seek out that will suggest the trend is reversed in some first-world countries in the past couple of years, but that's no where near enough time to draw conclusions.

Is there real evidence that men with greater "health" (besides the obvious, of, say, having a crippling disease) or "reputation" have more children?

I'm sorry, but this sounds like "women only chose alpha males" junk to me.

1. https://en.wikipedia.org/wiki/Income_and_fertility

2. https://www.statista.com/statistics/241530/birth-rate-by-fam...

[JumpCrisscross]

> Do you have any evidence that wealthier men have more babies?

Broadly, yes--wealthy people have more kids than poor people [1]. The confounding variable is market opportunity: when opportunity is high, the opportunity cost of kids goes up, which causes wealthier people to have fewer kids.

[1] https://pmc.ncbi.nlm.nih.gov/articles/PMC10427476/

[SamBam]

That study is hardly strong enough to make that statement that firmly. "Broadly," only if you exclude all of the Western world, and much of the rest of the world as well.

The study cites a dozen or so papers saying:

> Within contemporary Western populations, wealthier, higher status men tend to have lower fertility. In low and middle-income countries where populations are at different stages of this transition, women in wealthier households have fewer children on average. Over the course of the fertility transition, wealthier families also reduce their fertility earlier and more dramatically than the rest of the population.

They then essentially do a big regression analysis to say that if you take your material wealth and your education together, which they call your market opportunity, there is a strong negative relationship between that and fertility. Then if you take that same material wealth and your agricultural wealth together, there is a weaker positive relationship between that and fertility. So basically agricultural wealth (land and livestock) may be weakly correlated with having more kids, but other kinds of wealth aren't.

(And that's ignoring the fact that the chi-squared analysis said that their model was a poor fit anyway, but they hand-wave that away by saying that that's probably just because they had too much data.)

Finally, and importantly, the original statement by GP was that there was a sexual selection that favoring rich men. That is, that rich men would be selected by women and have more children. This study does not address that at all, as it measures household wealth, household education and number of children per woman, not per man.

[ninetyninenine]

Per my hypothesis I never said wealthier men should have more babies. Birth control is a factor here.

Women do marry and prefer richer men. Hypergamy is scientifically true, you can look it up if you want. But birth control changes the outcome even though hypergamy is an influencing factor.

In addition I said health and reputation are factors. So a man with good health but low wealth has one positive factor in his favor.

I feel your entire reply is rude and over the top. Calling my statement junk is not conducive to discussion.

[SamBam]

Ok, fair enough, I didn't mean to be rude. It's just that it sounds a lot like stuff that people who push fairly sexist stuff say.

The thread is about evolution, and sexual selection in the context of evolution generally implies having an evolutionary fitness. I missed the part about birth control, since then we're not really talking about whether sexual selection is having a role in human evolution.

In the context of sexual selection affecting evolutionary fitness, it seems clear that there is an inverse relationship between wealth and number of offspring.

I am not sure if there are any scientific studies purporting to link "reputation" and either marriage or offspring. Do you know of any?

[ninetyninenine]

>In the context of sexual selection affecting evolutionary fitness, it seems clear that there is an inverse relationship between wealth and number of offspring.

This inverse is caused be birth control and economic circumstance. For the poor person, more kids means more kids on the farm to work. So the poor person chooses to have more kids via not using birth control.

For rich people in rich areas, more kids equals more college tuition to pay. So the rich person chooses to have less kids via using birth control.

That's what causes it. I'm too lazy to cite sources but this comes from anthropology 101 it's textbook stuff. And like most anthro stuff the studies are qualitative, so take from it what you will.

>I am not sure if there are any scientific studies purporting to link "reputation" and either marriage or offspring. Do you know of any?

Just google it. I hit a result here:

https://en.wikipedia.org/wiki/Hypergamy

It's even in the wikipedia. It's also quite obvious if you've interacted with a lot of women before.

Look I know there's this woke movement that likes to cover up a lot of the dark stuff surrounding human behavior. Men and women have dark sides and this is just one of the darker things about women: Hypergamy. I think the thing that makes it more intriguing then the dark side of men is that culture and society basically masks this fact about women.

You see the double standard here? You can call men dumb and into boobs and butts and physical pleasures but to even mention something superficial about women you became all reactive about it like it's sexist. Men ARE into boobs and butts, that's just a fundamental truth and it's not sexist. Neither is this. It's also obvious.

[dekhn]

I believe we are currently measuring recent functional selection on humans and it's non-zero. That is, empirically you are incorrect.

[washadjeffmad]

Interesting. So how do you explain menopause and other population or age scale adaptations?

Humans aren't individuals, no matter how certain blips of modern culturalism pretend.

[toasterlovin]

If there's a fertility gradient based on heritable traits then there is evolution happening.

[JumpCrisscross]

> There's no meaningful selection pressure in our environment that kills people before reproductive age

War and disease. Rich countries can afford defence and healthcare. Poor countries cannot. (Within rich countries, the kids of the rich see war and disease less. They're more likely to be in offices, not on the battlefield and they're more likely to be educated and vaccinated.)

And even rich countries have periodic selection pressures. Natural disasters. Pandemics. Addiction epidemics. Propensities towards violent altercations or risk-taking behaviour. (Exhibit A: young men in cars.)

[immibis]

Does everyone have two children?

[_DeadFred_]

That's what the build up of plastics in our testicles are for.

[mattigames]

I have always considered that a bug, not a feature.

[snarf21]

Really? I was under the understanding that we have continued to get taller and bigger driven by out our access to nutrition and medicine over the last couple of centuries.

[InfiniteLoup]

Is this really a genetic adaptation to the environment or rather fulfilling the inherent growth potential that would otherwise be inhibited by nutrient deficiency?

[_DeadFred_]

By all the 'no one under 6'2"' tinder jokes I'd say it's being incorporated into genetics.