By John Dodge
Posting in Education
A Yale University study says women will be shorter and heavier in the future. It also concluded that Darwin's natural Selection theories still apply despite contemporary beliefs to the contrary.
Thin may be in, but by 2049, the average women will be a touch "chubbier and shorter," according to a Yale University study on natural selection gleaned from two recent generations of women.
Actually, thin is sort of out given the unhealthy and sometimes deadly effects of starvation diets on models who face the unemployment line if they don't remain in the words of one article "boney apparitions." Things are headed in the opposite direction anyway, says the new study.
Writing in the Proceedings of the National Academy of Sciences, Sean G. Byars and three fellow researchers said traits can be predicted for the next generation of women based on factors with 2,000 women in the famous Framingham Heart Study which began in 1948. For nine years, I lived in Framingham from whose population the initial 5,209 men and women were rescruited for the study which continues to this day.
Descendants of the women in The Framingham Heart Study on average are predicted to weigh about a kilogram more and be two centimeters shorter. If that's bad news, here's the good: women will also have lower blood pressure and chloresterol. Ths study also found women will have babies up to five months earlier and go through menopause up to 10 months later, resulting in a longer child-bearing period.
The study results would seem to validate "evolutionary biological principles" posited by Charles Darwin in "The Origin of the Species" 150 years ago.
"We found that natural selection is acting to cause slow, gradual evolutionary change," the researchers said in the PNAS article. The study strongly disputes the contemporary and population notion that medicine-inspired longevity means that natural selction no longer applies.
How the study was done is synopsized in a press release put out by Yale two weeks ago.
"The reason is that traits that enable women to have children will continue to be subject to selection. As a first step, the Yale researchers measured the individual reproductive success of two generations of more than 2000 women who participated in the Framingham study and had reached menopause. They then surveyed the traits that conferred reproductive success. After adjusting for environmental factors such as income, education and lifestyle choices such as smoking, the researchers estimated the heritability of traits by applying correlations among all relatives. They also adjusted for the indirect effects of selection by measuring the impacts the traits have on each other – such as whether high blood pressure is correlated with lower or higher age of sexual maturity."
Using statisical analysis, the researchers were able to determine which traits would be "conferred" on the future generation of women.
Follow me on Twitter.
Nov 2, 2009
Beauty is in the eye of the beholder. The issue of weight in women is taken as black and white. That is fat = ugly, thin = beautiful. Where does that leave woman of normal weight? Also, the so called skeleton models of the runaways, which are basically walking cases of anorexia and bullimia. I personally don't find attractive ... There also the cultural factor as elderblake mentioned, where a not so slim Marylin was considered a goddess in her time. Not to mention that there are some places in the world where culturally fuller women are considered more attractive, perhaps because of the association that such shapely bodies have with fertility. By selling the girls the idea that Barbie is the idea of a beautiful adult woman (she's not even proportioned in realistic human dimensions!: http://www.neversaydiet.com/slideshow/if-barbie-were-real-woman?nlcid=dt|10-28-2009|') which is not achievable, we set them in a path of personal dislike since they won't be able to achieve that standard. As mentioned elsewhere, the role of too much fattening food and not enough physical activity can't be overemphasized since obesity rates in the US are soaring, especially in children, which when adults will continue to be so unless something drastic like a gastric bypass is done to them. Perhaps the predeposition to be fat exists in most people, but has been distorted significantly because of the distortion in serving sizes. The other factor mentioned is the use of increased use of contraceptives by women, which I suspect might mess up their normal hormonal balance, probably contributing in some cases to lower fertility and in others, higher obesity. One factor which is not clear how they accounted for is income, given that, generally speaking, lower income people would tend to have more children as well as tend to be more obese, given that high calorie foods are relatively cheap, while healthier alternatives are more expensive. I guess, in the end, we'll have to wait and see how it turns out. One thing that seems flawed in the study, though, is how can they predict something using such a small sample size through such a short period of time and worse of all, localized in a particular area. What happens, for example if there is a large, sudden influx, of say, thin and tall people?
Even Miss Munro , the 1950s sex pot is now regarded as a bit beefy. Was thought then to have an absolutely divine shape(I was there at an impressionable age) A thing called TWiggy appeared in the 1960s and was the grandmother of the present day skin and bone models. Predicting the future is a thing that almost always is wrong.
There was study a few years back that showed a statistically significant higher rate of breast cancer in women with "denser' breast tissue. Small but statistically significant.The study also mentioned that it was only including women that had regular mammograms and had done so for a number of years. Nobody seemed to put the obvious two and two together. The obvious conclusion was that the radiation from mammograms caused more cancer in women with dense breast tissue than it did in women with less dense breast tissue. A perfectly logical result from what we know of radiation, even x-rays. But not apparently what anyone in the medical field wanted to consider. Just like no one apparently wants to suggest that as previous commenters have pointed out -quite probably less attractive women feel more gain by having children than attractive (thinner, better built, taller ) women do. I am quite sure that a serious study would show that the world population as a whole is getting dumber too and for exactly the same reasons. The dumb are having more children. And now days even a dumb kid with dumb parents can survive to reproduce about as well as anyone else.
Well, all I can say is that my lovely wife is six feet tall. I just thought this was an interesting study. Thanks to all for your comments.
What...I'm not sure if anything I post about this would make any sense. As fast as our environment is changing, any study done today will look silly in maybe 5 - 10 years. Check back for updates.
I would like to know how they concluded women would be shorter when every generation of women (and men) for years has been steadily getting taller. To me their height conclusion makes every conclusion this study has made to be suspect.
The most important result of this study is that evolution is struggling to deal with the effects of contraception. According to natural selection that which we find attractive should reproduce more. Contraception has changed this. More generally unattractive women are more insecure regarding their attractiveness and, thus, place a greater emphasis on achieving the objective of having children early, whereas, attractive women are less insecure and can put this objective on hold while they achieve other objectives, like fulfilling careers...etc. The more unattractive women, thus, end up having children earlier and as a result over the course of their reproductive years they have more children which would explain such results. More attractive women are having more sex, except they're using contraception. There are certain profound implications when you consider the effects of contraception and natural selection. Attractiveness must equate to fitness. If short, fat women are fitter then we would find them attractive since it would be good for our genes to realise that. These results confirm what I've been thinking about such effects. That is, that the less fit are having more children. Fitter, i.e., more attractive individuals are having more sex, they're just using contraception.
You don't need a expensive scientific study to prove this in the UK just go along to your local shopping mall.....
a "science" writer who does not know that body fat is a function of caloric intake has no more reason to be discussing darwin than michael behe does discussing mousetraps. "Our aims were to demonstrate that natural selection is operating on contemporary humans" and therefore they hit it. btw :"There is a definate advantage to living beyond reproductive years as long as the elder members contribute to the survivability of the younger generation." is a false statement. "contribute to the reproductive success would probably be a true one. this issue is debated.
Evolutionary changes in 2 generations? Even Darwin would wince. Alternatively, some have posited, there's hormones in the food supply, phytoestrogens abound in soy based everything and we generally eat too much sugar. Resulting in earlier first menstration, increased weight and loss of height from vitamin D and calcium deficiency. Not quite rickets but most are vitamin D deficient. And the dairy industry bamboozled the last few generations into believing that you get all the calcium you need from milk. We drink more milk than any other nation yet have the highest osteoporosis rate. Hmmmmm..
Actually, my analysis of the data says that it is socio-economic changes that drove the reproductive numbers, and not inherit traits. There is a definate advantage to living beyond reproductive years as long as the elder members contribute to the survivability of the younger generation. This may be access to economic resources not available to people without older relatives. It also manifests as an advice and knowledge pool, as well as a possible child care source. 2 generations of influence are not enough to make a significant statistically measureable change in inherited characteristics of such a homogenious sample.
That is actually retrograde evolution. If you look at the trend of what's fashionable, it correlates directly to the advancement of technology and the overall increase in the speed in which we live our lives. The massive increase in frequency of changing fashionability are an anomaly, not a rule. However, I can say that Mr. Dodge is certainly a member of the generation largely responsible for ruining this world by basing rules on said exceptions. People don't become fat because skinny is perceived as unhealthy, they become fat because gen-x and late boomer parents instilled in their children an unquenchable thirst to be lazy. Then they publish studies like this to further defend their own delusions of being good, responsible parents who simply had kids who went wrong.
To use this study to dispute the ?contemporary and population notion? that medicine-inspired longevity means that natural selection no longer applies is scientifically inaccurate. It is a fact that technology greatly reduced (but not yet eliminated, although altered) the course of natural selection in modern humans and the results of the study (carefully planned and well conceived) have a high statistical probability of being true in the correctness of the results provided by the data - what is inaccurate is the interpretation of the results. They just show that in the population studied, in the study period stated (that comprises periods with both efficient and inefficient birth control), shorter and heavier women chose to have more children - nothing else. That is because the biological capacity of women to have offsprings is greater than the present-day cultural choice (and choice capability) to have less than in the previous ages, making the second factor prevailing for several generations (at least in the western world) thus limiting the course of evolution. To say that all women will become chubbier is somewhat arbitrary, even in the population studied - if the culturally induced procreational choices change, the corporeal biostats might change too.
Are you kidding - shorter! Never have I seen more young women growing taller than in the last decade. I've visited a number of cities throughout central USA and Canada in the last 20 years and there are a lot more tall (above 5' 8") young women. I know I'm not the only one to notice this either - others have pointed this out to me as well.
The future is here, well we're halfway there anyway, women are definately more obese now and they consider that the norm and actually tell themselves they have average bodies. Don't they have mirrors in their houses or does their simple mind distort reality like those carnival mirrors? Show me a women who would happily stand naked in front of a mirror and i'll point to her guide dog.
Dunno....but good question...it would seem that most women in the study or many were from the pre-fertility clinic days. Or the study took them into account....JD
It makes sense that women living longer beyond their reproductive years makes no difference to natural selection. But what percentage of children are now being born to people who can't reproduce without a fertility clinic?