Evolution is Ongoing
Brains have shrunk by about 10% in the past 5,000 years. Average shoe sizes have grown four sizes for men and women since 1900, and heights are all over the map. Americans, who were among the world’s tallest people in 1900, have leveled off in the past 25 years (averaging 5-foot-10 for men and 5-foot-4 for women). Europeans have continued growing—particularly in Holland, where men now average over 6-feet tall. The Japanese, among the world’s shortest people in 1950, have grown nearly 5 inches, on average, since then, to 5-foot-7 for men.
Full article on the modern-day maladies caused by evolution.
You’re not giving us an explanation for these developments. Years ago, changes occured because they had evolutionary survival value. But surely an extra 5 inches isn’t helping Japanese men survive any better today.
I’m not sure whether this is evolution or de-evolution. Bigger feet. Smaller brains. The theory that the human race is evolving over time seems illogical (to me) when you start with George Washington, John Adams and Thomas Jefferson and trace a line to Bill Clinton, George W. Bush and Barack Obama.
On the other hand, it seems unlikely that these developments are random.
It makes me wonder what sorts of adaptations are necessary for the modern computer age: being near-sighted, short attention span, tiny fingers (for tiny keyboards), and an intense patience for waiting in line at Central Market on Saturday morning?
The whole divergence in population (the taller, elite race, and the shorter, laboring class) has been discussed before. H.G. Wells postulated what life would be like in the future, and he arrived at the same conclusion.
http://en.wikipedia.org/wiki/The_Time_Machine
On the other hand, a lot of birth control advocates tend to think that as populations became more affluent, they decrease the number of children they have. If this is the case, as nations become more developed, birth rates will fall. There will be no population divergence, and the result will be the homogenous gene pool that was also discussed in the article.
Better nutrition likely accounts for the increase in Japanese height. The same effect of genes on the body can vary depending on whether they are turned on or off by external factors. Arguably, evolutionary survival has rewarded traits that are now coming into play, such as the ability to adapt to changes in environment. More food and less disease might have turned on certain genes telling Japanese bodies to not stop growing as early. Maybe these genes have always been turned on in the Dutch. Or maybe the Dutch would not survive famines as well as the Japanese. Certainly, Native American populations have not fared as well under plentiful food supplies.