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Are Humans Still Evolving? (yahoo.com)
21 points by edw519 on Oct 26, 2009 | hide | past | favorite | 26 comments



The Framingham study is a good study for what it is about (risk factors for heart disease), but the study is probably inadequate for studying general selection pressure on the whole human population.

http://norvig.com/experiment-design.html

The key quotations in the article are

Douglas Ewbank, "Those changes we predict for 2409 could be wiped out by something as simple as a new school-lunch program."

Steve Jones, "Uniquely in the living world, what makes humans what we are is in our minds, in our society, and not in our evolution."


Degenerate diseases don't kill you before you can have children.

"Those changes we predict for 2409 could be wiped out by something as simple as a new school-lunch program."

Stupid. African nations have both the highest birth rates and the worst nutrition. If anything, expected good health after reproductive age negatively correlates with fecundity.

"Uniquely in the living world, what makes humans what we are is in our minds, in our society, and not in our evolution."

If Steve Jones knows of some supernatural force that excludes the operation of the human body from physical reality, he should describe that force and submit it to a physics journal. Otherwise, yes, minds are minds, but minds are not magic: they're meat.


Norvig's advice is cautionary not contingent. When you want to study the effects of natural evolution on human populations (really any population) you're forced to do a wide, long observational study including as many subjects and cofactors as possible. Since that's pretty nearly prohibitively expensive, you're really better off just seeing if you can get someone else's data just like Stearns did.

This data specifically doesn't have a lot of power to generalize to populations outside of Framington. Additionally, making bold future predictions is not something that scientists like to show one another, just news reporters. What it does, though, is show support to already leading theories. Stearns is quoted in an NPR interview saying the real point that "the result that we have here is no surprise to any evolutionary biologist. It's exactly what we expected to see."

No matter what the possible confounding factors may have been, the fact that when decent statistical methods were used to control for and limit just to correlations that could be feasibly tied to evolutionary processes the remaining effect fits the predictions developed by theories made prior to this result means that the data provided some interesting justification.

Stearns also is quoted in that the study attempted to "lift the level of discussion and get everybody on the same page." It's not groundbreaking, it's just some solid human-based evidence for things long predicted. The hype is centered around news stories which pick up on the wide future predictions (an offhand, light comment in the interview) and the philosophical/moral implications of evolution playing police state on our futures (which is a suitable target for arguments about statistical weakness and Stearns himself brings up that only about 5% of the variability was involved in this evolution trend).

All the study really says is that, yes, like we thought, somewhere deep inside human cultural motion is a definite seed of evolutionary guidance. It takes 60 years of intense observation to see it, but it almost certainly exists and plays some tiny role.

Which is kind of a boring news story.

[NPR interview: http://www.npr.org/templates/story/story.php?storyId=1140814...]


People will look like the people who most have children.

Do you have children? If not, then the people of the future will probably look less like you and more like the people who compounded faster than you did.


Agreed, human evolution will be determined less by selection pressures and more by breeding pressures. Those who breed early and often will dominate the future as late pregnancies (35+) typically bring higher complications, earlier births and typically less healthy offspring.

However society will play its pressures too. Access to adequate and nutritious food can be more important than healthy genes (after all you need proper nutrition for your genes to express themselves correctly during your development) so a 22 year old mother on welfare with 5 kids and no child support is going to have a problem raising healthy children.

In the US, access to healthcare will certainly play a huge part in the future (presuming it doesn't change vastly over a long time). An imbalance in access can give an unnatural advantage to the unhealthy.

The potential for the future of evolution in our species is amazing. We have so many more variables in play that will be tweaking us, instead of standard variables for hunter-prey relationships. It raises a lot of questions about what our species will be like in a few hundred-thousand years.


"The bastard science of eugenics, [Jones] says, will haunt humanity as long as people are tempted to confuse evolution with improvement."

"confuse evolution with improvement" I agree.

"bastard science of eugenics" What an appropriate slur: "bastard". Well, whoever parented that bastard wins this debate ---whatever that debate might be--- when you and the children you didn't have all die. You can go sit in the ground with the Quakers and the Spartans.


Shakers? Quakers are the religious group that prefer the warm fuzzy feelings to dogma. Shakers were the celibate sect.


Don't need to be celibate to go extinct. Remember Nixon? Hoover? They used to run America from colonial times until... well, know any Quakers?

"Although official Quakerism may not have abided the activities of many of these feminists, the Quaker belief that "in souls there is no sex," and the opportunities provided Quaker women to preach, hold meetings, and write epistles, gave rise to the high percentage of Quakers among the "mothers of feminism," including Angelina and Sarah Grimké, Lucretia Mott, Abby Kelley, Susan B. Anthony, and Alice Paul."


Also, the 2007 paper by Hawks et al indicated that evolution had accelerated over the past 10,000 years.

Dec. 10, 2007 - Researchers discovered genetic evidence that human evolution is speeding up - and has not halted or proceeded at a constant rate, as had been thought - indicating that humans on different continents are becoming increasingly different.

"We used a new genomic technology to show that humans are evolving rapidly, and that the pace of change has accelerated a lot in the last 40,000 years, especially since the end of the Ice Age roughly 10,000 years ago," says research team leader Henry Harpending, a distinguished professor of anthropology at the University of Utah.

Harpending says there are provocative implications from the study, published online Monday, Dec. 10 in the journal Proceedings of the National Academy of Sciences:

"We aren't the same as people even 1,000 or 2,000 years ago," he says, which may explain, for example, part of the difference between Viking invaders and their peaceful Swedish descendants. "The dogma has been these are cultural fluctuations, but almost any Temperament trait you look at is under strong genetic influence."

http://unews.utah.edu/p/?r=120607-1


There seem to have been some adaptations including central nervous system genes, which may have increased fitness in a hierarchical agricultural society.

For example new versions of serotonin transporters in both Europe and east Asia (such as SLC6A4). There are other neurotransmitter-related changes, also changes in genes that affect brain development. East Asians have a new version of DAB1, a gene involved in the development of the layers of the cerebral cortex, while there is a fairly common new version of NKX2-2 (a brain homeobox gene) in Europeans.

http://biology.plosjournals.org/perlserv/?request=get-docume...

http://www.plosgenetics.org/article/info:doi/10.1371/journal...


I feel stupid now that I noticed there wasn't any cool pictures of arbitrarily human faces evolving 10 generations - or did I miss something?


First phrase of just the second sentence:

Despite the long-held view that natural selection has ceased to affect humans because almost everybody now lives long enough to have children

Uh, what? Do people actually think that?


Well, A 2006 report on global mortality rates [1] suggests that regardless of country, the average human does reach sexual maturity. It follows that fitness, amongst humans, isn't significantly affected by survival / longevity. After all, if we live to reproduce, then anything that sets in after that event is irrelevant from an evolutionary standpoint.

I could see that reasoning giving rise to the phrasing used in the article.

[1]: http://www.who.int/whosis/whostat2006_mortality.pdf


After all, if we live to reproduce, then anything that sets in after that event is irrelevant from an evolutionary standpoint.

I imagine there are some people who reason that way, but they'd be ignoring the obvious survival benefits of having parents (and extended family) to help raise a child.


It doesn't follow that we aren't still evolving, only that there isn't sufficient selection pressure to push evolution in a particular direction. We're still evolving, just randomly in all directions. We're stocking up on mutations for the next round of selection pressure nature throws at us.


I'm thinking resistance to birth control is going to evolve really fast, probably within a few generations. Or perhaps if there's a gene associated with forgetting to take birth control.


Interesting idea, but I think most mutations that would so severely change how a woman responds to hormones would also be debilitating to the point that she wouldn't be able to have children.


That's a good point. Perhpaps it could be a very indirect effect then. For example I heard some antibiotics lower the effectiveness of birth control, so perhaps a mutation that makes you get strep throat more often? Just a hypothetical example..

But that makes me wonder, whatever mechanism antibiotics use to lessen the effectiveness, couldn't a small mutation use the same mechanism?


There are already lots of fertile girls who have adverse reactions to hormonal contraceptives.


But then they know the pill doesn't work, and will likely use a different form of birth control. In order for the mutation to spread, it would need to make the pill not work silently. And even that would be difficult, because women should realize the pill is not working because they're still menstruating.


The problem is that other forms of birth control all suck in one way or another. Your chances of successfully preventing pregnancy go down if you can't use hormonal contraceptives. That's why they were a big deal when they were invented.


women on the pill still menstruate


Only if they do the 3 weeks on, 1 week off cycle that is commonly prescribed. Women who continue to take the hormone pills can skip menstruation.

Related to the current discussion, women would quickly realize that their menstrual cycle is not lining up with the week of non-hormone pills.


You cannot stop evolution, you can only change the fitness criteria.


What, no cyber-eyes and metal arms? I'd like to sign up for a different future please!


Can someone hook edw519 up with searchyc.com?

It seems all he does is post dups: http://news.ycombinator.com/item?id=891137




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