Do you have a specific example that demonstrates this?

Most people are fixated on nutrition to make people taller but nutrition can only do so much.

Imagine if you've a goal to increase height of people from 165 to 190cm with minimum number of generations. How will you go about it.

Easiest and fastest way is to have two tall parents breed. You'll see it happen within 2 generation.

Now, if you improve nutrition of people who are 165cm today. How many generations of better nutrition does it require to make them reach 190cm? Certainly more than 2 generations.

Point is that, if you think "sexual selection" is not fast enough to take people from 165 to 190 within few generations (as is the case with Dutch) then better nutrition certainly is not either.

Cattle/pet breeder do it all time.

Cattle breeders don't allow inferior males to breed at all and typically a single bull can have thousands of progeny via artificial insemination. That doesn't happen in human societies where most males will have a chance to breed. Also the time-spans are far longer for humans than cattle where the next generation is ready for breeding two years after birth.

> That doesn't happen in human societies where most males will have a chance to breed.

We can get a precise idea about this since it shows up in the genetic record and over the long term it's under half. A lot more men than you think are cuckolds.

>That doesn't happen in human societies where most males will have a chance to breed.

How do you know most males get chance to breed in our society?

Just because a lot of men end up married and have kids to show doesn't mean they are their biological kids.

These days I see single moms are marrying guys who simply take care of the kids they already had.

Meanwhile Denmark sperm export is doing good.

These days many people are getting suprize on 23andme when they come to know about their lost connections.

If anything what 23andme etc have demonstrated is overall how faithful women have been because the surprises are very much in the minority. i think we can agree that Danish sperm export has played little or no role in the growth of Dutch people since 1850.

let me get this straight, so in order to make the increase from 165 to 190cm in a few generations, both parents have to already be tall? Because 165 is not tall and that already fucks up your premise

Yea, but if we've average 165, there will be some taller than 165 and some shorter than 165. We might as well have someone 190, we can use them to breed tall population.

And but how do you achieve that just using nutrition?

Effect of nutrition on height is overstated. Unless someone is malnutritioned, their height won't benefit much with better nutrition

We can even see this in cattles, if you start with a short cattle, no matter how much you feed it for generations, they'll still he shorter than one you can get from tall breed.

A couple generations seems short. This study pointed to 50+ generations for significant behavioral changes in foxes.

https://www.nature.com/articles/s41559-018-0611-6

The best example comes from Darwin's finches and the work of Peter and Rosemary Grant. Here's a good article outlining some of the things they've documented: https://www.wired.com/2016/10/legendary-biologists-clocked-e...

I suppose my main issue is that I just don't think the passage of time since the mid 19th century is long enough to give a natural selection answer for humans. Perhaps it might be more believable if Holland had suffered great loss of male life in WW1/WW2 and smaller men were disproportionately affected leaving tall men to breed widely. But Holland wasn't in WW1 and its loss of life in WW2 was relatively light.

It's been 150 years, roughly 3 generations can fit in that. Also, you are improving average height of population here, so if you simply remove a lot of people with below average height, average benefits a lot.

More like 5 generations but there was no one in charge of this breeding programme. It seems that a lot of Dutch men decided to voluntarily forego sex but to raise the children of women who were breeding with the tall men. And this phenomenon to have been peculiar to Holland. Just doesn't seem believable.

Traits can be bred into dogs within four generations.

(Yes, I am aware…)

He doesn't because is BS.

It's really not. Speciation is slow (on the order of 50 generations at minimum), but selection is very powerful, and can cause large phenotypic changes in the span of tens of generations instead.