Evolution's Path May Lead To Shorter, Heavier Women

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.'"

Comments

Re:Fat Americans Breed Fat Americans! Film at 11

[Baron_Yam]

Any GP or OB/GYN will tell you that there is a minimum percentage of body fat below which a woman won't even menstruate.

They'll also tell you a woman should gain some weight during pregnancy, and that generally speaking the outcome of the pregnancy is better if a certain amount of weight is gained (unless the woman is already overweight, of course).

Again, I don't think they're saying thinner = bad, I think they're saying the population is shifting towards the optimum range. Skinny women have less, and less healthy children on average, so the average weight is rising by a small amount as they're outbred by heavier women.

There will be an upper limit to this effect as well - morbid obesity is not a good thing for getting or being pregnant, either.

Re:Idiocracy is classist bullshit

[Maxo-Texas]

Your facts are less correct than they were 50 years ago.

http://www.nytimes.com/pages/national/class/index.html
"The movement of families up and down the economic ladder is the promise that lies at the heart of the American dream. But it does not seem to be happening quite as often as it used to."

http://www.npr.org/templates/story/story.php?storyId=4662456
Eighty percent of Americans still believe it's possible to pull yourself up by the proverbial bootstraps. That's according to a New York Times poll reported last week, but a recent mobility study suggests the American Dream may be more style than substance.

http://en.wikipedia.org/wiki/Social_mobility
Upper nonmanual occupations have the highest level of occupational inheritance. [3]

http://money.cnn.com/2009/02/27/news/companies/lashinsky_hurd.fortune/index.htm?postversion=2009030310
As his father did before him, Hurd attended the Browning School - a prestigious all-boys school where classmate Jamie Dimon, now CEO of J.P. Morgan Chase, remembers seventh-grader Hurd as a good basketball player

The wealthy own the media and push the "you could be wealthy!" idea hard. It helps keep the lower class folks voting against their own self interests. It's why the wizard of wall street pays a lower tax rate on his monumental earnings than his secretary pays on her salary.

There is a tiny chance you will break into the wealthy classes. But, for the most part, they pass the good jobs down to their own. Just look at the way hollywood has been taken over by 2nd and 3rd generation actors. CEO jobs are less obvious but essentially the same.

Any idiot can bankrupt themselves-- but it takes a lot more than simple hard work to get into the executive class.