Forgot your password?
typodupeerror
Biotech Science

Evolution's Path May Lead To Shorter, Heavier Women 411

Posted by kdawson
from the short-but-neither-brutish-nor-nasty dept.
Hugh Pickens writes "Yale University researchers believe that if evolutionary pressures of sexual selection and reproductive fitness continue for another 10 generations, the trends detected in their study may mean that the average woman in 2409 AD will be 2 cm shorter, 1 kg heavier, will bear her first child five months earlier, and enter menopause 10 months later. 'There is this idea that because medicine has been so good at reducing mortality rates, that means that natural selection is no longer operating in humans,' says Stephen Stearns of Yale University. 'That's just plain false.' Stearns and his team studied the medical histories of 14,000 residents of the Massachusetts town of Framingham, using medical data from a study going back to 1948 spanning three generations, and found that shorter, heavier women had more children than lighter, taller ones. Women with lower blood pressure and cholesterol were also more likely to have large families as were women who gave birth early or had a late menopause. More importantly, these traits are then passed on to their daughters, who also, on average, had more children. The study has not determined why these factors are linked to reproductive success, but it is likely that they indicate genetic, rather than environmental, effects. 'The evolution that's going on in the Framingham women is like average rates of evolution measured in other plants and animals,' says Stearns. 'These results place humans in the medium-to-slow end of the range of rates observed for other living things.'"
This discussion has been archived. No new comments can be posted.

Evolution's Path May Lead To Shorter, Heavier Women

Comments Filter:
  • makes one wonder... (Score:2, Interesting)

    by StripedCow (776465) on Sunday November 01, 2009 @09:52AM (#29941305)

    http://science.slashdot.org/article.pl?sid=09/07/27/1455253 [slashdot.org]

    is shorter and heavier "more beautiful"?

  • by jdevivre (923797) on Sunday November 01, 2009 @10:04AM (#29941347)
    The problem with most biologists and geneticists (I'm one) is a lack of objectivity. They should talk to more engineers when solving problems (I'm one of those too).

    Process A
    Most planned pregnancies happen in later life.
    Most unplanned pregnancies happen while drunk.
    Most drunk intercourse is with the first willing partner.
    Most willing partners are more homely than gorgeous.
    Most homely women are shorter and fatter.

    Process B
    Most unplanned pregnancies are followed by unplanned marriages.
    Most marriages starting with an unplanned child are followed by subsequent progeny (it started with sex, so sex is what you do together for the first while)
    Most social traits carry on through generations - daughters of young mothers often have early pregnancies (these may involve factors expressed in Process A)

    Thus, homely Mom, homely daughters, Mom got drunk and had sex early so why can't I, followed by more homely daughters...

    Where's the mystery?
  • by houghi (78078) on Sunday November 01, 2009 @10:12AM (#29941395)

    When I was young, an ongoing joke was the question 'Is fertility passed on by the parents." Now you could start asking that question. Also there is a trend of finding slimmer women more attractive. In the past this ment that those would be having more children.

    However with the pill and other contraceptives, it looks as if the most attractive (in a biological way) females have LESS babies.

    The result of this all will be that we have a lot of ugly kids. Perhaps the division becomes so great that we will separate as species and become two.

  • by BadAnalogyGuy (945258) <BadAnalogyGuy@gmail.com> on Sunday November 01, 2009 @10:31AM (#29941483)

    A "breed" of humans with a genetic propensity towards violence and lawlessness... I hope no one mentions the elephant in the middle of the room.

    That's right. Pit bulls.

  • by Anonymous Coward on Sunday November 01, 2009 @10:31AM (#29941485)

    Tall, thin women also tend to be wealthy, either from having been born into wealth, or from having married into wealth (obviously, they have higher value on the meat market) or from having earned it themselves (if you don't think tall thin women make more than short fat ones, you are kidding yourself).

    And, based on many studies I read about in college, wealthy people tend to have fewer children, if any at all. The average was something like 1.1 per family I think.

    Poor people, on the other hand, breed like rabbits. The average I read was close to 6 per family. And here's the kicker: in western culture (not just America) the abundance of cheap fattening food combined with jobs that are not physically intensive means the poor can get fat. Once-upon-a-time the poor were all farmers and therefore got enough exercise to stay thin. Now the poor all work in retail (or similar) and can get quite fat.

    So, yes, the trend will be for short-fat women. But the trend in rich families will still be for tall, thin women.

    I wonder if our race will bifurcate into two separate species someday.

  • Unconvincing. (Score:3, Interesting)

    by MaWeiTao (908546) on Sunday November 01, 2009 @10:34AM (#29941491)

    I'm not convinced by these researchers' claims. Is there a trend towards people getting shorter? I thought the opposite was true. As for obesity, that's another story. But what I am convinced this reflects is not an evolutionary trend but rather a socioeconomic one. The better off people are the less likely they are to have children. So poorer people are the ones having children and unlike most of the rest of the world lower-class Americans are very likely to be obese. Do this study in parts of Asia or Africa and these researchers would be saying the trend was towards thinner humans. The US actually bucks the trend established by most developed nations in that many people still tend to have a few children, in Europe and Asia you're lucky if they have one. I'm not sure why there would be a shift towards bearing children sooner considering most people seem to be waiting longer to have kids. Again, it might simply be a reflection class.

    That seems like a big assumption to me given how many variables exist. An interesting thing a gynecologist told me a couple of years ago was that obese women tend do deprive the fetus of nutrients more so than your average women, so they tend to have underweight babies far more frequently. So this evolutionary tend doesn't seem like a particularly good thing to me. But then there are so many variables affecting humanity that these findings are likely meaningless.

  • Re:Idocracy (Score:5, Interesting)

    by Dachannien (617929) on Sunday November 01, 2009 @10:42AM (#29941537)

    There's also something wrong with spouting forth conclusions and condemning the opposing viewpoint as being idiotic without citing any evidence (which makes this [xkcd.com] somewhat ironic, I guess).

    The Wikipedia article on the subject [wikipedia.org] is convoluted and doesn't really offer any strong conclusions, but at least some studies reported in the article have suggested a small negative correlation between intelligence and fertility (i.e., number of offspring), and another study showed a strong negative correlation between education and fertility (and education is sometimes used as a proxy for measuring intelligence). There's also a well-known negative correlation between economic well-being and fertility which may be related.

  • by dachshund (300733) on Sunday November 01, 2009 @10:54AM (#29941611)

    Also there is a trend of finding slimmer women more attractive. In the past this ment that those would be having more children. However with the pill and other contraceptives, it looks as if the most attractive (in a biological way) females have LESS babies.

    It's not quite as simple as that. As I've grown older (my 30s) I've discovered (the perhaps obvious fact) that "slimness" is largely a function of age. It amazes me how easy it is for my early-20s colleagues to stay skinny while drinking corn syrup all day long, and the same goes for females. I look ridiculously thin in pictures of me when I was the same age (and at the time I thought I needed to slim down, yikes). Its obviously possible to stay thin as you get older, but it becomes harder.

    The point I'm trying to make here is that our cultural fetish for "skinny = beautiful" can also be viewed as a fetish for "younger = beautiful". And youth and fertility go together like a horse and carriage. I'm not sure what this has to do with this study, since they obviously controlled for age, but don't imagine that things are as simple as you make out.

    Also, let's pray there are no women reading Slashdot, oy...

  • Re:Idocracy (Score:1, Interesting)

    by Jeremiah Cornelius (137) * on Sunday November 01, 2009 @11:04AM (#29941695) Homepage Journal

    The ignorance of the poor is social engineering, not genetics.

    The intelligence of the poor is on par with any other population - but the metrics are skewed for culture and training.

    The rich ARE evil. One of the principal lacts of their evil is to sponsor a media-culture that gets ordinary schmucks like yourself to identify emotionally with them, aspire to their condition, and to assume an attack on the values of the truly rich to be a personal threat to your own status and mobility.
    You are also trained to revile those perceived as less fortunate/gifted as yourself - never suspecting that to the real rich, the difference between you and the homeless doesn't amount to a rounding error.

     

    ...In 2006 and 2007, Goldman Sachs Group peddled more than $40 billion in securities backed by at least 200,000 risky home mortgages, but never told the buyers it was secretly betting that a sharp drop in U.S. housing prices would send the value of those securities plummeting.

    Goldman's sales and its clandestine wagers, completed at the brink of the housing market meltdown, enabled the nation's premier investment bank to pass most of its potential losses to others before a flood of mortgage defaults staggered the U.S. and global economies.

    Only later did investors discover that what Goldman had promoted as triple-A rated investments were closer to junk... [mcclatchydc.com]

  • by kanweg (771128) on Sunday November 01, 2009 @11:14AM (#29941761)

    In the Netherlands people marry rather late, and many women get their kids in their (late) thirties. A good portion of women of that age miss the boat. There is an enormous selection pressure going on. Ignoring the emerging trend of freezing eggs, one may expect that in a couple of generations Dutch women will be able to bear children at even older age, and may well live even longer than they do now.

    Bert

  • by Geoffrey.landis (926948) on Sunday November 01, 2009 @11:23AM (#29941837) Homepage

    Poor people, on the other hand, breed like rabbits. The average I read was close to 6 per family.

    You should consider reading something that actually quotes facts someday, instead of Rush Limbaugh, or whoever it is you get your made-up facts from.

    So, yes, the trend will be for short-fat women. But the trend in rich families will still be for tall, thin women. I wonder if our race will bifurcate into two separate species someday.

    No, by the logic you just quoted, the fat women are fat because they're poor-- you just told me that the fatness was because of "the abundance of cheap fattening food combined with jobs that are not physically intensive means the poor can get fat. " That's not hereditary.

    In any case, the birth statistics you quoted imply that the "tall, thin, rich" women die out, and are replaced from the pool of "short, fat, poor" women (whose progeny become tall and thin, before they die out and are replaced in turn.) So the species doesn't bifurcate (at least, not according to the logic you give).

  • Re:Idocracy (Score:3, Interesting)

    by 4D6963 (933028) on Sunday November 01, 2009 @12:04PM (#29942081)

    One of the principal lacts of their evil is to sponsor a media-culture that gets ordinary schmucks like yourself to identify emotionally with them, aspire to their condition, and to assume an attack on the values of the truly rich to be a personal threat to your own status and mobility. You are also trained to revile those perceived as less fortunate/gifted as yourself - never suspecting that to the real rich, the difference between you and the homeless doesn't amount to a rounding error.

    Hallelujah. Which yields weird and amusing behaviours from middle class nowhere-near-rich people. They're against taxes on the rich as if they ever were going to make it one day (this being said I can relate to that delusion, I always believe that I'm about to make it big and picture myself in ten years with more money than I could need), and they don't want any "handouts" to poor people, even though that's tens of millions of Americans we're talking about.

    The American lower-class doesn't even exist, if you pay attention to political debates. I wonder if it's because no one wants to hear about the poor, even those who are on their way to poverty, or if because there's so many poor, and so little difference between the poor and the middle class compared to the upper class that the lower class is now part of the middle class.

  • Troll (Score:3, Interesting)

    by Dunbal (464142) on Sunday November 01, 2009 @12:18PM (#29942171)

    Dear Sir/Madam,

          Evolution doesn't work that way. You're talking about genetic drift, which is not the same.

          Kthxbai

  • by Anonymous Coward on Sunday November 01, 2009 @01:14PM (#29942468)

    How would you know the sperm recipient wouldn't be one of the "shorter and heavier women"? I mean there's no reason tall and skinny chicks should drop by a sperm bank yes?

  • by Dysphoric1 (1641793) on Sunday November 01, 2009 @03:10PM (#29943202)

    Idiocracy is classist bullshit that comforts rich wankers who desperately want to believe that they're rich because of some inherent superiority

    The part that I find most humorous about this fact is that our DNA doesn't care what we do for a living or how big our houses are. It doesn't care how intelligent we are either. The goal of our DNA is procreation. So if the rich have fewer children than the poor, then the rich are, by definition, genetically inferior to the poor, and it is natural selection that makes them a minority.

    Funnier yet, it is the rich who can afford to have the most children, so the poor are beating them despite having a severe handicap.

  • by yndrd1984 (730475) on Sunday November 01, 2009 @03:52PM (#29943550)

    Class is relatively fixed, do not confuse some dynamic movement in income as social mobility, most people behave like atoms in gas.

    Are the atoms in a gas fixed? I'm sorry, but the article you've cited does a poor job of supporting that idea. On the other hand, according to this [wikipedia.org]

    42 percent of those whose parents were in the bottom quintile ended up in the bottom quintile themselves, 23 percent of them ended in the second quintile, 19 percent in the middle quintile, 11 percent in the fourth quintile and 6 percent in the top quintile

    Which means that children in the lowest 1/5 of households have an even shot at moving halfway across the class spectrum. It may not be a perfect meritocracy, but it's no caste system, either.

  • by Shirakawasuna (1253648) on Sunday November 01, 2009 @04:54PM (#29944144)
    You touched on a key point: selection is contingent on environmental pressures, which need not be constant. The researchers are extrapolating 400 years into the future based on 50 years of data in a single town in Massachussets. Have they even pinpointed the selective pressure(s) doing this, assuming their results are significant? How do they know they'll continue and weren't random (random as in non-predictable)?
  • by Anonymous Coward on Sunday November 01, 2009 @04:59PM (#29944180)

    Also I might point out that having an abundance of food and not having to do jobs that are physically intensive are characteristic of the rich, not the poor. The United States is one of the collectively wealthiest societies in the world, and it is also one of the fattest. Poor people are more skinny; go to India or China and check it out some time. There are vastly more skinny people on Earth than there are fat people, and they aren't more well off as this guy is suggesting.

  • by Alsee (515537) on Sunday November 01, 2009 @05:30PM (#29944470) Homepage

    First, modern humans have been in our current form for something like ten thousand generations

    We obviously haven't grow wings lately, but it would be a mistake to think we haven't changed at all. A rather substantial number of genes have been identified as having been selected during the last several tens of thousands of years, and in fact quite a few genes have been identified undergoing current positive or negative selection. A simple case is something like lactose tolerance which has been independently evolved and selected in the last ten to fifteen thousand years. I recall an article about the number of copies of some brain genes increasing on that time scale (some genes have multiple copies, which increases the amount of protein generated from them, which affects function). A fascinating current example is that scientists have found certain genes for bipolar disorder and other mental disorders are currently undergoing POSITIVE evolutionary selection, because certain classes of emotionally unstable people are inclined unstable relationships or promiscuity, and they tend to fail to use contraception. So these emotionally unstable people tend to have many serial relationships leaving a string of children behind to be raised by the more stable partner. It is a kinda twisted example, but it is a very real example of a very real direction currently being explored actively selected for in human evolution. It's a striking and memorable example because it illustrated how evolution doesn't care what we thing is "good" or bad", evolution just selects whatever "works" to yield more offspring.

    Giving birth earlier and later menopause all sound like things that would improve selective fitness... but the question is, if they really are selected for, why weren't they selected for five thousand years ago?

    The most significant event in human evolution was a huge surge towards larger more flexible brains. Humans are born with "freakishly" huge heads compared to any other primate. Most species can stand and walk virtually from the moment of birth, but human babies are born with such oversized heads that their necks can't even lift their heads.

    The limiting factor in head-size at birth is the size of the mother's pelvis and birth canal. Labor and birth is extraordinarily difficult and painful in human females exactly because of the difficulty of trying to birth a huge-headed baby through a barely large enough birth canal.

    Up until the advent of modern medicine, a staggering percentage of women died in child birth. I'm not sure, but the number 20% pops to mind. Virtually all of those fatalities are derive from the difficulty and failure to deliver the too-large baby's head through the too-small birth canal.

    Modern diets produce faster growth rates in children, and modern medicine eases birth or even uses a C-section to completely avoid the birth canal. In the past pregnancy in younger girl was simply a death sentence for both the mother and baby, physically incapable of delivering the baby through her more limited birth canal. Puberty can and has come at younger ages simply because it is no longer fatal.

    As for the delay in menopause, very few people used to lived long enough to even hit menopause. There was negligible pressure for women to remain fertile beyond their typical lifespan. Additionally modern women quite often use birth control to delay child bearing. Modern women generally want to finish college or even establish careers first. There is often talk of hearing the "click ticking", with women delaying their child bearing years right up against the menopause limit. The menopause limit has recently become an extremely active factor strangling the number of children a woman can have. In fact a significant number of career women losing the ability to have even a desired first child because they waited too long.

    ten generations is trivial

    It obviously does not absolutely indicate the long term future of the entire human race, but even just two or

  • by ucblockhead (63650) on Sunday November 01, 2009 @05:43PM (#29944584) Homepage Journal

    Except that is actually not at all the results they got. They studied weight, etc. *after* they had babies.

    They did not find that slimmer women end up having more babies. To do that, they'd have to take all of these measures *before* women had children and compare that to their future success. Because of the way they measured, what they *actually* found was that women who have more children end up fatter.

    That doesn't sell the papers, though.

  • by Grishnakh (216268) on Sunday November 01, 2009 @07:00PM (#29945194)

    You've basically answered your own question. There's lots of hot women in Manhattan, and none in Appalachia, and it's because of exercise. To get around in Manhattan, unless you have a limo or cab take you door-to-door everywhere (that gets expensive quick), you take the subway, and walk many blocks between your destinations and the subway stations. I've spent a couple of weeks there: being a Manhattan citizen means lots of walking, lots more than a typical suburban American does. I haven't been to Europe yet, but I'm pretty sure it's much the same: people use mass transit a lot, and live more densely, and end up walking a lot to get from place to place. This is very different from many Americans who have a car in the garage they drive to work and walk a few hundred yards (meters) to their desk.

    Now, add in the corn syrup. Most of our mass-market food in this country uses corn syrup, or its variant high-fructose corn syrup (even bread!). It's really hard to find foods that don't have either that, or the even worse hydrogenated oils. People in other countries don't eat very much corn syrup at all, if any, and normally use cane sugar for sweetening, which is healthier since it needs to be broken down by the body before it can enter the cells.

    And yes, overweight women (or men) are NOT attractive or healthy. Only obese Americans would ever try to fool themselves into thinking that. A BMI between 20 and 25 is healthiest, regardless of what the pro-obese crowd tells you. I think they're trying to fool people by equating "non-obese" with "seriously underweight".

  • by phision (836909) on Monday November 02, 2009 @01:17PM (#29951988) Journal
    Of course you are talking about the legitimate children. But consider that the rich people have more illegitimate children than the poor - maybe without even knowing. As I remember somewhere about 20% of the people are conceived in infidelity. This skews the statistics quite a lot.

In a consumer society there are inevitably two kinds of slaves: the prisoners of addiction and the prisoners of envy.

Working...