Are Humans Still Evolving?

[Randy Reed 0]

http://news.yahoo.com/s/time/20091024/hl_time/08599193175700Human Evolution: Are Humans Still Evolving? Modern Homo sapiens is still evolving. Despite the long-held view that natural selection has ceased to affect humans because almost everybody now lives long enough to have children, a new study of a contemporary Massachusetts population offers evidence of evolution still in action.A team of scientists led by Yale University evolutionary biologist Stephen Stearns suggests that if the natural selection of fitter traits is no longer driven by survival, perhaps it owes to differences in women's fertility. "Variations in reproductive success still exist among humans, and therefore some traits related to fertility continue to be shaped by natural selection," Stearns says. That is, women who have more children are more likely to pass on certain traits to their progeny. (See the top 10 scientific discoveries of 2008.) Stearns' team examined the vital statistics of 2,238 postmenopausal women participating in the Framingham Heart Study, which has tracked the medical histories of some 14,000 residents of Framingham, Mass., since 1948. Investigators searched for correlations between women's physical characteristics - including height, weight, blood pressure and cholesterol levels - and the number of offspring they produced. According to their findings, it was stout, slightly plump (but not obese) women who tended to have more children - "Women with very low body fat don't ovulate," Stearns explains - as did women with lower blood pressure and cholesterol levels. Using a sophisticated statistical analysis that controlled for any social or cultural factors that could impact childbearing, researchers determined that these characteristics were passed on genetically from mothers to daughters and granddaughters.If these trends were to continue with no cultural changes in the town for the next 10 generations, by 2409 the average Framingham woman would be 2 cm (0.8 in) shorter, 1 kg (2.2 lb.) heavier, have a healthier heart, have her first child five months earlier and enter menopause 10 months later than a woman today, the study found. "That rate of evolution is slow but pretty similar to what we see in other plants and animals. Humans don't seem to be any exception," Stearns says. (See TIME's photo-essay "Happy 200th Darwin Day.")Douglas Ewbank, a demographer at the University of Pennsylvania who undertook the statistical analysis for the study, which was published Oct. 21 in the Proceedings of the National Academy of Sciences (PNAS), says that because cultural factors tend to have a much more prominent impact than natural selection in the shaping of future generations, people tend to write off the effect of evolution. "Those changes we predict for 2409 could be wiped out by something as simple as a new school-lunch program. But whatever happens, it's likely that in 2409, Framingham women will be 2 cm shorter and 1 kg heavier than they would have been without natural selection. Evolution is a very slow process. We don't see it if we look at our grandparents, but it's there."Other recent genetic research has backed up that notion. One study, published in PNAS in 2007 and led by John Hawks, an anthropologist at the University of Wisconsin at Madison, found that some 1,800 human gene variations had become widespread in recent generations because of their modern-day evolutionary benefits. Among those genetic changes, discovered by examining more than 3 million DNA variants in 269 individuals: mutations that allow people to digest milk or resist malaria and others that govern brain development. (Watch TIME's video "Darwin and Lincoln: Birthdays and Evolution.")But not all evolutionary changes make inherent sense. Since the Industrial Revolution, modern humans have grown taller and stronger, so it's easy to assume that evolution is making humans fitter. But according to anthropologist Peter McAllister, author of Manthropology: the Science of Inadequate Modern Man, the contemporary male has evolved, at least physically, into "the sorriest cohort of masculine Homo sapiens to ever walk the planet." Thanks to genetic differences, an average Neanderthal woman, McAllister notes, could have whupped Arnold Schwarzenegger at his muscular peak in an arm-wrestling match. And prehistoric Australian Aborigines, who typically built up great strength in their joints and muscles through childhood and adolescence, could have easily beat Usain Bolt in a 100-m dash.Steve Jones, an evolutionary biologist at University College London who has previously held that human evolution was nearing its end, says the Framingham study is indeed an important example of how natural selection still operates through inherited differences in reproductive ability. But Jones argues that variation in female fertility - as measured in the Framingham study - is a much less important factor in human evolution than differences in male fertility. Sperm hold a much higher chance of carrying an error or mutation than an egg, especially among older men. "While it used to be that men had many children in older age to many different women, now men tend to have only a few children at a younger age with one wife. The drop in the number of older fathers has had a major effect on the rate of mutation and has at least reduced the amount of new diversity - the raw material of evolution. Darwin's machine has not stopped, but it surely has slowed greatly," Jones says. (See TIME's special report on the environment.)Despite evidence that human evolution still functions, biologists concede that it's anyone's guess where it will take us from here. Artificial selection in the form of genetic medicine could push natural selection into obsolescence, but a lethal pandemic or other cataclysm could suddenly make natural selection central to the future of the species. Whatever happens, Jones says, it is worth remembering that Darwin's beautiful theory has suffered a long history of abuse. The bastard science of eugenics, he says, will haunt humanity as long as people are tempted to confuse evolution with improvement. "Uniquely in the living world, what makes humans what we are is in our minds, in our society, and not in our evolution," he says.I think it's funny that he thinks Neanderthal would kick our ass today. The fact is they were bigger and stronger, had larger brains and jaws and teeth thatcould chew tire iron and we still kicked their ass 40,000 years ago into extinction. In fairness, we didn't physically kick their ass but we had a genetic trait that enabled us to survive that they didn't have. We were marathoners and they were sprinters. Which is also funny since he mentions aborigines being able to out sprint us. I do agree that evolution wise we are likely to become lazy slobs though. Our poor health is due to bad diets and lack of exercise and it only takes a trip to Walmart to see the evidence. Overweight people are more likely to have health problems that they pass along as well.

[colonel Feathers 5]

Depends on your definition of evolving.If you meanthat 10000 years from now you couldnt reckognize humans from today, I doubt it.

[vbnautilus 48]

Interesting topic. One thing that has struck me as one the of weirder trends in fertility recently is the impact of fertility drugs. Those women who in previous times would be unable to produce offspring are now producing octuplets and sextuplets by the dozen. Seems to me this will have some pretty profound consequences in the long run. About Neanderthal being better than us because they were bigger: they were just adapted to a different environment. We don't need to be as physically strong now because of technology. And bigger brain does not mean smarter brain -- elephants have some of the biggest brains, but are not the smartest. The brain has clearly evolved for greater intelligence since Neanderthal. But the most significant changes in humanity are now due to cultural evolution. The plasticity of our brains is really evolution's crown jewel since it allows for "software"-like changes without very much change in the hardware. There has been some debate in primatology over the last five years on whether other apes show any culture at all. While there do seem to be some isolated examples that qualify, the ability to pile learning upon learning and progress over time is ultimately a phenomenon unique to humans.

[BigDMcGee 3,352]

Proof that we're evolving in the right direction...Gingers extinct in 100 years, say scientists....

[Randy Reed 0]

Interesting topic. One thing that has struck me as one the of weirder trends in fertility recently is the impact of fertility drugs. Those women who in previous times would be unable to produce offspring are now producing octuplets and sextuplets by the dozen. Seems to me this will have some pretty profound consequences in the long run. About Neanderthal being better than us because they were bigger: they were just adapted to a different environment. We don't need to be as physically strong now because of technology. And bigger brain does not mean smarter brain -- elephants have some of the biggest brains, but are not the smartest. The brain has clearly evolved for greater intelligence since Neanderthal. But the most significant changes in humanity are now due to cultural evolution. The plasticity of our brains is really evolution's crown jewel since it allows for "software"-like changes without very much change in the hardware. There has been some debate in primatology over the last five years on whether other apes show any culture at all. While there do seem to be some isolated examples that qualify, the ability to pile learning upon learning and progress over time is ultimately a phenomenon unique to humans.

I agree it's an interesting topic. I think most people think that human have stopped evolving, at least in the basest sense of adapting to living in the wild. Obviously there will be many genetic changes to come base on mating and our ecology. I also think most people view evolution in the balloon sense of about 6000 years and kind of freak if you bring up something like homo-sapien vs neanderthal. ( I do think that would make a great thread if only for the humor value). I think people are uncomfortable thinking of an ancester roaming wild in packs like animals. Looking at local clubs on Saturday night does bring it all back though, eh?Homo-sapiens were lucky enough to be able to run. They could run long distances unlike very few other animals. We (they) couldn't out sprint an antelope but they had persistence and ran down animals. Cheetahs, antelope, deer etc., were all very fast short distance but would tire out and lay down which made them great prey for homo sapiens who could go long distances. Keep in mind there were no weapons or tools for the millions of years and it was a huge advantage to be able to have access to such a great protien source. Neanderthal were cold weather and when the climate changed warmer they were screwed. They couldn't run down anything and starved.

[coug2828 8]

most of the people i come into contact with seem to be evolving in the wrong direction.

[JoeyJoJo 18]

[TheNumbersGame 0]

Evolution only means change or adaptation, so it's pretty obvious that we are. Agriculture had a big impact on it, when humans started farming. Took us generations to get used to foods like eating wheat and corn in abundance. Eventually we got bigger, mostly in the last millenium. Just look at how small medieval armour was.Cool to think I could storm Camelot by myself.

[Mercury69 3]

Does "backwards" count evolutionary-wise?

[speedz99 145]

Stearns' team examined the vital statistics of 2,238 postmenopausal women participating in the Framingham Heart Study, which has tracked the medical histories of some 14,000 residents of Framingham, Mass., since 1948.

That's my hometown, bitches! Front lines of scientific discovery, motherfuckers! Balls!

But not all evolutionary changes make inherent sense. Since the Industrial Revolution, modern humans have grown taller and stronger, so it's easy to assume that evolution is making humans fitter. But according to anthropologist Peter McAllister, author of Manthropology: the Science of Inadequate Modern Man, the contemporary male has evolved, at least physically, into "the sorriest cohort of masculine Homo sapiens to ever walk the planet."

I'm surprised they'd make that statement without mentioning that our size change since the Industrial Revolution has nothing to do with evolution, per say.

Homo-sapiens were lucky enough to be able to run.

You know luck had nothing to do with it.

Evolution only means change or adaptation.

Not really. Those can be parts of evolution...learning to farm is not "evolving", per say.Per say!

[TheNumbersGame 0]

I didn't mean learning to farm was evolving really, i just meant it affected our evolution.

[vbnautilus 48]

Evolution only means change or adaptation, so it's pretty obvious that we are. Agriculture had a big impact on it, when humans started farming. Took us generations to get used to foods like eating wheat and corn in abundance. Eventually we got bigger, mostly in the last millenium. Just look at how small medieval armour was.Cool to think I could storm Camelot by myself.

But the question was not "have we recently evolved" it was about the present -> future. Compared with the time at which agriculture came on the scene, at this point there is very little selection pressure on humans: virtually anyone who wants to reproduce can do so.

[BigDMcGee 3,352]

GINGERS ARE GOING TO BE EXTINCT! DOn't you guys know what this means?!? No more Vosses, for one

[JoeyJoJo 18]

I'm surprised they'd make that statement without mentioning that our size change since the Industrial Revolution has nothing to do with evolution, per say.Not really. Those can be parts of evolution...learning to farm is not "evolving", per say.Per say!

Per se.

[Sal Paradise 57]

: virtually anyone who wants to reproduce can do so.

fuck you.

[vbnautilus 48]

fuck you.

i said "virtually" anyone.

[TheNumbersGame 0]

It was only an example, you could name any number of things that have affected the species over its history. I have a question, it kind of ties in with the ginger thing, I want to see what people think. What about mixed-race children? I would say that it's only in the past couple hundred years or so that races have been intermingling in such large numbers. Now there are people with several heritage lines - white, black, asian, hispanic, native american, middle-eastern, and say, maybe east european, all within the last few generations, and the numbers are growing steadily.How, if at all, will this affect the species?

[SGFULTON83 0]

That is awesome.

[timwakefield 68]

Raymond Kurzweil, singularity, drastic changes in life expectancy, human/computer hybrids, etc. As many calculations as "all human brains!" Good lord! Also, if science fiction has taught me anything, they will probably feed on human brains as well. Basically though, our computers today are dumber than a fly. In half a century they'll be as smart as everybody ever. Maybe.For whatever reason, this other graph/timeline of his kind of spooks me out. All human brains! He could have made that sound less ominous, I think.

[JoeyJoJo 18]

All human brains! He could have made that sound less ominous, I think.

When will computers equal all human brains PLUS all hippopotamus brains?And when will computers learn to love, Tim? When will they learn to love? <---say that in a Jerry Seinfeld type voice

[JoeyJoJo 18]

And when will computers learn to love, Tim? When will they learn to love?

[speedz99 145]

Per se.

Thank you.

[uncooper 1]

When will computers equal all human brains PLUS all hippopotamus brains?

I read last night that male hippopotamus power struggles are often settled through ritualized pooping contests punctuated by foul smelling belches used to disorient the belch-ee. And that herrings can communicate with farts.

[JoeyJoJo 18]

I read last night that male hippopotamus power struggles are often settled through ritualized pooping contests punctuated by foul smelling belches used to disorient the belch-ee. And that herrings can communicate with farts.

In The Ghost and the Darkness (a pretty terrible movie) Val Kilmer says that hippos fart through their mouths.But you don't mess with hippos.

[brvheart 1,752]

In The Ghost and the Darkness (a pretty terrible movie)

1st date with my wife.