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Humans haven't stopped evolving

harvardmagazine.com

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Re: Humans haven't stopped evolving

#41

Post by retrac »

remarkEon wrote: post #12
delichon wrote: post #9

Earlier quoted context omitted.

There's been no biological change in humans in 40,000 or 50,000 years. Everything we call culture and civilization we’ve built with the same body and brain. -- Stephen Jay Gould, "The Spice of Life", 2000 Gould was an evolutionary biologist and Harvard professor, and one of the most prominent popularizers of evolution since Darwin, but somehow believed that it doesn't apply to modern humans.

That's such an extreme claim. It defies common sense. You'd have to proclaim that there was some event that _stopped_ evolution in humans, universally. How is that even possible? Especially 50k years ago. I'd be a little more forgiving if the claim was that evolution stopped in, say, 1999.

Emphasis should be placed on "everything we call culture and civilization". There is a thought experiment that might help. Imagine we had a time machine, and no scruples, and we could go back and pluck babies from the past to experimentally raise them in modern American families. I'm pretty sure Gould would have argued that babies from 40k years ago would grow up to be behaviourally indistinguishable from modern humans.

Re: Humans haven't stopped evolving

#43

Post by derektank »

gblargg wrote: post #31
hn_throwaway_99 wrote: post #18

Given that fertility rates are currently plummeting worldwide, the principles of natural selection would dictate that humans are currently undergoing very high selection pressure for specific traits. Basically, any genetic trait that causes people today to think "You know, I think I'm going to remain childfree" is specifically selected against, and any trait that causes people to want more children will be selected f…

[flagged]

>People aren't born not wanting to have kids, since all their ancestors did.

What evidence do you have that all their ancestors wanted to have kids? I can think of a lot of reasons why people may have had kids without necessarily wanting them. They wanted to have sex in an era before birth control. They were pressured into it by the social norms of their local community. They were raped. Etc.

I have a lot of criticism of the childfree movement but I think it’s pretty disrespectful to assume they’re not being honest when they say they don’t want to have kids and that they’ve always felt that way.

Re: Humans haven't stopped evolving

#44

Post by bebe83949rj »

nozzlegear wrote: post #30
bebe83949rj wrote: post #16

[flagged]

Humans are the only mammals with genders at all. Are you confusing gender with sex?

Both are synonyms! Like when pretend "woman" sports are not for woman, but "female" only! Or woman should be in mans only prison, to get raped!

Re: Humans haven't stopped evolving

#45

Post by chmod775 »

derektank wrote: post #43
gblargg wrote: post #31

Earlier quoted context omitted.

[flagged]

>People aren't born not wanting to have kids, since all their ancestors did. What evidence do you have that all their ancestors wanted to have kids? I can think of a lot of reasons why people may have had kids without necessarily wanting them. They wanted to have sex in an era before birth control. They were pressured into it by the social norms of their local community. They were raped. Etc. I have a lot of criticis…

Birth control is older than the Bible[1], it just wasn't as effective. Humanity as a whole was very aware how babies come to be.

Ways to have fun without coitus aren't a recent invention either.

Human reproduction and raising children is an unusually taxing, time-, and resource-intensive process, which is why we've applied our considerable intellect to plan for that since forever.

[1] https://en.wikipedia.org/wiki/History_of_birth_control

Re: Humans haven't stopped evolving

#46

Post by remarkEon »

retrac wrote: post #41
remarkEon wrote: post #12

Earlier quoted context omitted.

That's such an extreme claim. It defies common sense. You'd have to proclaim that there was some event that _stopped_ evolution in humans, universally. How is that even possible? Especially 50k years ago. I'd be a little more forgiving if the claim was that evolution stopped in, say, 1999.

Emphasis should be placed on "everything we call culture and civilization". There is a thought experiment that might help. Imagine we had a time machine, and no scruples, and we could go back and pluck babies from the past to experimentally raise them in modern American families. I'm pretty sure Gould would have argued that babies from 40k years ago would grow up to be behaviourally indistinguishable from modern huma…

Well, evaluating the nature of this thought experiment reveals what you actually believe about human evolution and development. I find it extremely hard to believe that someone from 40k years ago would be indistinguishable from humans today. Believing this requires you to imagine that there are no genetic selection pressures for things like intelligence, behavior, physical ability ... 40k years ago had Earth as an almost entirely different planet. Europe was frozen for most of the year, for example. There were no trees. Very, very hard to believe that people born back then could grow up to sit in front of a laptop today.

Re: Humans haven't stopped evolving

#47

Post by margalabargala »

derektank wrote: post #43
gblargg wrote: post #31

Earlier quoted context omitted.

[flagged]

>People aren't born not wanting to have kids, since all their ancestors did. What evidence do you have that all their ancestors wanted to have kids? I can think of a lot of reasons why people may have had kids without necessarily wanting them. They wanted to have sex in an era before birth control. They were pressured into it by the social norms of their local community. They were raped. Etc. I have a lot of criticis…

Involuntary reproduction has been a tiny tiny minority of births for the past few millenia at least. It happens and is awful but it should not be construed to constitute a large part of any person's ancestry.

Re: Humans haven't stopped evolving

#48

Post by margalabargala »

remarkEon wrote: post #34
RajT88 wrote: post #15

Earlier quoted context omitted.

Rather a lot more things about human genomic history are known today compared to 2000. Discoveries about being able to process lactose and when those genes evolved all were after 2000, for example. Does it excuse Gould for making such bold claims? You have to decide I guess. That is a lot fuzzier.

I guess I would need to read more of what Gould wrote. For example, did he claim that evolution in other species also stopped?

I think the claim that humans stopped evolving is an uncharitable reading.

Another would be, 50k years is such a narrow window that evolution cannot be observed across it.

Re: Humans haven't stopped evolving

#49

Post by jiggawatts »

It is well established that evolution is driven not only by fitness in the trivial sense of "survival or death", but in large part by mate selection.

(Disclaimer: The rest is a personal theory with zero scientific support.)

This begs the question: selection based on what? In many bird species it is the complexity of the male's song, or the colourful beauty of his feathers. There are "dances" and courtship rituals in many animals, including even insects.

Humans almost certainly also subject to evolution caused by the evolutionary pressures of mate selection!

This is best said by Anthony Hokpins in Westworld: https://www.youtube.com/watch?v=OjsGJOXhPGU

"I read a theory once that the human intellect was like peacock feathers. Just an extravagant display intended to attract a mate. All of art, literature, a bit of Mozart, William Shakespeare, Michelangelo, and the Empire State Building—just an elaborate mating ritual.

Maybe it doesn't matter that we have accomplished so much for the basest of reasons. But, of course, the peacock can barely fly. It lives in the dirt, pecking insects out of the muck, consoling itself with its great beauty."

Which is a good bit of drama, but... if true, what are the consequences for the evolution of the human species?

Assume for a moment, that yes, women are attracted to male intelligence, which men show off with music, art, and "great works".

The obvious immediate effect is that this causes the average intelligence of Homo Sapiens to increase over time.

But the secondary effect is more interesting: judging intelligence benefits from more intelligence! As the next generation of women inherit greater intelligence, they become better judges of male intelligence, more picky and precise. This forces male intelligence to increase ever faster to keep up with the "rising demand". Rinse and repeat.

I can't prove, but strongly suspect that this is the case.

Birds of Paradise become "more beautiful" on the scale of aeons because more beauty in the males doesn't improve the judgement of the females.

Humans become more intelligent on the scale of mere millenia because more intelligence does improve the judgement of the females.

Re: Humans haven't stopped evolving

#50

Post by keeda »

Am I the only one who thought that was a given based on phenomena like this:

https://www.nationalgeographic.com/science/article/bajau-sea...

we all are not quite freediving most of our waking lives, but the daily pressures of modern urban living must be exerting a similar level of evolutionary pressure on us.

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