Friday, December 28, 2007


Since I was a child, I have thought that evolution must have accelerated, due to deaths from alcohol, drugs, firearms, automobiles, obesity, other modern hazards and their combinations (armed fat people on meth driving drunk, for example). However, I would occasionally hear or read some educated person going on about how evolution had now stopped, since nearsighted people could wear glasses and wouldn't be eaten by tigers or fail as hunters (I guess the idea was). I didn't want to reject that idea out of hand, however wrong it sounded. After all, if the infant mortality rate were 50% or higher back in the day, then maybe they were being selected for something like "fitness" whereas in modern times most babies that are born can reach maturity.

It seems like I have waited a few decades for someone to clear up this question. Finally I have some strong new evidence on the accelerated side of the argument. A study published earlier this month (Dec 10) by actual geneticists and anthropologists, not the armchair variety, determined that human evolution has accelerated by up to a hundred times as human populations increase and move into new environments with new diets and new conditions. Authors are John Hawks, Eric T. Wang, Gregory Cochran, Henry C. Harpending, and Robert K. Moyzis. The article mainly refers to changes in human evolution since the beginning of agriculture, not the industrial age, but the same rules should hold true for recent centuries. Math is involved here as well as actual gene frequencies. Recommended reading: The original article at PNAS. John Hawks weblog. BBC. SciAm. U of Utah Press release. Utah pdf. ScienceDaily. LAT. SMH.

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