Human evolution remains in the news these days, and seems less to do with Charles Dawin’s 200th birthday than with some significant new studies being released by prominent biologists. For example, Yale University evolutionary biologist Stephen Stearns recently led a team focusing on women’s fertility in Framingham, Massachusetts, including some interesting evolutionary predictions.
"Variations in reproductive success still exist among humans, and therefore some traits related to fertility continue to be shaped by natural selection," Stearns says.
According to Time Magazine:
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."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.
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.
Click here for the Time Magazine article.
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