Evolution vs society

[FinalEnigma]

Ok, example here lets say a bunch of people move to the top of a mountain, naturally, they will develope better lungs(since the air is less dense there and better lungs are required to get the same level of oxygen) This does not affect their genes however, so these improved lungs will not pass on to their descendants. In a non-societal population(I.e. animals) natural selection would take over and the ones with inferior lungs would die out, while those with genetically superior lungs would have a greater chance of reproducing. In a human society, natural selection doesn't apply, since we have no predators and nothing weeds out the inferior people to prevent them from reproducing so logically, except for natural selection that breeds us to be more attractive to members of the opposite sex(which might well be counterproductive to evolution), i don't see how it applies to the human race. or if there was some kind of mutation which causes an individual/group of individuals to be vastly superior(such as something along the lines of Donal Graeme from dorsai! and his intuitive logic[a system by which he came to logical conclusions instantly using all available information.] or blayze and his interval thinking[basically the same thing]) to the rest of humankind somehow and that got distributed around to the entire race because this vast superiority causes them to be significantly more attractive to the opposite sex.

My questions for debate are

Does human society eliminate the applicability of natural selection?

If not why not?

If so does this mean that the human race logically cannot evolve once it reaches a society?

If so is there anything we can do about it short of regulating who can marry and reproduce and who cannot? What would that be?

[Jose]

This question comes up from time to time. I think it arises out of the "simple stories" that are presented to illustrate how evolution works--such as the "less fit" being eaten by predators. Let me tell a different story to create a different image. I've told this story here and there in these forums, so if you've read it before, bear with me.

It's the "berry patch scenario." We've got two tribes that live on opposite ends of a valley. Winter's coming on. It's been a bad year, so the berry patch in the middle of the valley doesn't have enough berries to support both tribes through the winter. Now, people have instincts just as animals do--inborn, genetically coded ways of responding to different types of situations. One tribe has mostly people with an instinct to share, and to respect diversity among people and among tribes. The other tribe has mostly people with the instinct that their own group is most important, and is certainly superior to other groups. In fact, they have no problem with fighting against other groups, because they "know" instinctively that they are "better."

Every time foragers from the two tribes encounter each other at the berry patch, the guys from the second tribe bean the other guys over the head with rocks. By spring, only the second tribe remains (though they've captured some of the other tribe's women).

Which tribe are we descended from?

We still have the instinct that our own group is somehow "better" than other groups, and we're willing to fight about it. Sometimes the fighting is over minor differences in the interpretation of the Holy Book (bombings in Belfast or in Baghdad); sometimes it's over bigger differences in religion (believing we have the moral right to bomb Iraq); sometimes it's over loyalty to soccer teams. We wear our colors and our hats and our hairstyles to help distinguish who is in which group.

- - - - - - -

Now, how does evolution work? Basically, there are only two rules. (1) Mutations happen--occasional changes in DNA sequence--leading to genetic diversity. (2) Some individuals have more offspring than others.

Well, we know both of these happen. We know they happen in human populations. Natural selection isn't just a matter of being eaten by predators; it's any advantage/disadvantage that affects the number of offspring. Just like people fighting over the berry patch, we have no idea that there's selection going on. We just live our lives, have kids, and die. We'll have to come back in several thousand years to see what course evolution took. We can't predict or direct the mutations, and we can't predict what the future will be like, so we can't purposely evolve to meet it. But if those two rules hold true--and they always do--evolution will occur.

[FinalEnigma]

Now, how does evolution work? Basically, there are only two rules. (1) Mutations happen--occasional changes in DNA sequence--leading to genetic diversity. (2) Some individuals have more offspring than others.

Well, we know both of these happen. We know they happen in human populations. Natural selection isn't just a matter of being eaten by predators; it's any advantage/disadvantage that affects the number of offspring. Just like people fighting over the berry patch, we have no idea that there's selection going on. We just live our lives, have kids, and die. We'll have to come back in several thousand years to see what course evolution took. We can't predict or direct the mutations, and we can't predict what the future will be like, so we can't purposely evolve to meet it. But if those two rules hold true--and they always do--evolution will occur.

ok, so evolution will occur. So slowly that it might as well not. yes, some people have more offspring than others, but that isn't defined by who is genetically superior. its defined(at least with regards to groups), if primarily by one attribute, by whoever is most attractive(I.e. if you've got one group of men that are super-studs and one group that are say, geeky scientists, the super-studs are more likely to have more offspring, but that doesn't make them superior.) also, 1)if whatever mutation occurred and 2)if it was beneficial and 3) if it was not overt(an overt mutation would cause the person to be rejected by society in the same way that any overt difference does I.e. smart kids in high school are outcasts 90% of the time because they are different, but being smart is definitely beneficial) and 4) if no accidents occurred to prevent them from reproducing and 5) if they and their descendants reproduced enough that the mutation would actually spread through the race. thats a lot of ifs.

and as for natural selection if it is only the ones who reproduce most that spread out their genes then will we become incredibly sexy mega-testosterone-producing(i believe that gives us our sex drive) really tall(man has [arguably]evolved since the medieval period to be taller. if it was evolution and not just better nutrition or something like that then its probably because women find taller men more attractive, which still is true meaning the trend will continue) people? Im not sure that would be useful as far as the evolution trying to prevent racial extinction line increased testosterone levels would make men more aggressive, meaning we'd be more likely to kill ourselves off. being tall would cause increased musculoskeletal and cardiac health issues, and make us easier to shoot if we went to war cause we are bigger targets. Also i would hypothesize that especially careless/less responsible people are more likely to produce a greater number of offspring by having unprotected sex before marriage with multiple partners. that probably wouldn't be a good way to evolve. i would also hypothesize(very tentatively since this is just a guess) that men drive evolution by having more children to an individual person than women as a result of playboy type men and the fact that women are not physically capable of having children as fast as men. also that there are more childless men than women and more women with children from one father than men with children from one mother.(more single women with children than men?)

[Jose]

ok, so evolution will occur. So slowly that it might as well not. yes, some people have more offspring than others, but that isn't defined by who is genetically superior.

Slowly, indeed. That's what makes people reluctant to accept it. They can't see it happen. We can see it happen with rapidly-replicating things with sloppy replication systems, like influenza virus, but people just say "yeah, but that's a virus so it doesn't count." As a general rule, no one ever notices evolution happening, because evolution requires replacing some genotypes with others, and that takes lots of generations.

I'll also suggest that the term "genetic superiority" is not very good. It's better to think of genetics that make the individual a better fit for the particular environment--which, in the case of crickets that live in caves, means their eyes don't develop. In humans, one of those genetic attributes turns out to be being afraid of the dark, or of monsters under the bed. If you're a wimpy weanie and don't go out at night, you don't get eaten. In Europe, "genetic superiority" at one time meant being a carrier of Cystic Fibrosis. Your kids might die if you married another carrier, but being a carrier made you more likely to survive Cholera. So, it's good to set aside the "superiority" idea, and leave it as "more offspring." All that evolution "sees" is passing on genes to offspring.

... its defined(at least with regards to groups), if primarily by one attribute, by whoever is most attractive(I.e. if you've got one group of men that are super-studs and one group that are say, geeky scientists, the super-studs are more likely to have more offspring, but that doesn't make them superior.)

Attractiveness is relevant for mate choice, but not for everything that's involved in reproductive success. So is disease resistance, for example. If that new tuberculosis strain takes off, that's going to be a big selective agent--the last I heard, it had killed 36 of the 38 people who'd gotten it. It's super-resistant to antibiotics, so there's no cure. Either you're resistant, or you're dead.

My point is that we can't predict what characteristics will turn out to be important in the environment of, say, 200 years from now.

...also, 1)if whatever mutation occurred and 2)if it was beneficial and 3) if it was not overt(an overt mutation would cause the person to be rejected by society in the same way that any overt difference does I.e. smart kids in high school are outcasts 90% of the time because they are different, but being smart is definitely beneficial) and 4) if no accidents occurred to prevent them from reproducing and 5) if they and their descendants reproduced enough that the mutation would actually spread through the race. thats a lot of ifs.

Yep. Lots of ifs. But keep in mind that what we think should be beneficial may not be the thing that leads to "more offspring." Statistical data show that the more educated people are, the fewer kids they have. This might suggest that we're selecting against education, because those who go to college eventually die out. (and, of course, we know that college is really hard on students' grandparents, who tend to die around exam time.)

and as for natural selection if it is only the ones who reproduce most that spread out their genes then will we become incredibly sexy mega-testosterone-producing(i believe that gives us our sex drive) really tall(man has [arguably]evolved since the medieval period to be taller. if it was evolution and not just better nutrition or something like that then its probably because women find taller men more attractive, which still is true meaning the trend will continue) people? Im not sure that would be useful as far as the evolution trying to prevent racial extinction line increased testosterone levels would make men more aggressive, meaning we'd be more likely to kill ourselves off. being tall would cause increased musculoskeletal and cardiac health issues, and make us easier to shoot if we went to war cause we are bigger targets. Also i would hypothesize that especially careless/less responsible people are more likely to produce a greater number of offspring by having unprotected sex before marriage with multiple partners. that probably wouldn't be a good way to evolve. i would also hypothesize(very tentatively since this is just a guess) that men drive evolution by having more children to an individual person tan women as a result of playboy type men and the fact that women are not physically capable of having children as fast as men. also that there are more childless men than women and more women with children from one father than men with children from one mother.(more single women with children than men?)

In short, there are advantages and disadvantages to many traits, which tend to lead selection to keeping those traits from becoming extreme. You mention frequent sex with many partners; one would think that this would tend to lead to an increase in genes for promiscuity. It might, but it's countered by the fact that children are more likely to survive and do well themselves if they have both parents to care for them--and if they have grandparents to help as well. This selects against promiscuity and for stable monogamous relationships. Of course, we've invented a culture that glorifies the nuclear family, rather than the extended family, so we're probably selecting for some novel characteristics that we can't think of right now (or at least that I can't think of).

It's complicated, this evolution and selection business. Everything tends to interact with everything else. I sometimes like to ask, "when you think of members of the opposite sex, what are the features that you really pay attention to? AND which of those features do you really worry about with respect to your own attractiveness to others?" ...wait a bit... "Did everybody say Hair?" We're the only mammals that have hair that grows continuously, and has to be cut. And then, it's only our head-hair that does this. Eyebrows, the hair on our forearms, etc, all reaches a defined length and then stops--just like the hair on mice, dogs, deer, and other mammals. What selected for continuously-growing hair? Why, when the mutation appeared fortuitously, did it eventually become the norm? Probably because hair ornamentation/length/style helped us differentiate our tribe from other tribes; it became a part of our culture. And, apparently, it also became a feature that we use to determine attractiveness--so we not only look at others' hair, we also pay inordinate attention to our own. We selected not only for hair qualities, but also for the instinctive behavior of paying attention to it. Hair and attention to it apparently have been a part of the overall equation that works out as "number of offspring." It probably comes at a price, though. I bet growing hair uses up a measurable fraction of what food we eat, so there's a "cost" to growing it. Paying attention to it takes up brain-space that could otherwise be used for something else. Despite the disadvantages, we ended up with it because it led to a litttle better reproductive success.

Two more points come to mind: you mention accidents that could (and do) kill people. This happens, all right. It's part of that "number of offspring" business. If a boulder squishes you, you don't have many offspring after that. This isn't "natural selection" though, but an aspect of "genetic drift." In small populations, it can be a significant factor in evolutionary change.

The other point is that we shouldn't think of all traits as being selected for. Some may be there because they are genetically linked to something that is useful. Some may exist just because nothing has selected against them. I put tongue-rolling in this category. I can roll my tongue. My dad couldn't. Big deal. I can't think of anything useful about it.

In any event, those two "rules" really do seem to be the bottom line, even if it's rather an oversimplification to say so.