luni, 31 decembrie 2007

We are fast

We are fast, geologically time speaking. We are the Speedy Gonzales of the monkeys.

It looks like culture enhances variance. The cultural development acts as a chatalyst for genetic variance and selection.

It starts like this:

Genome study places modern humans in the evolutionary fast lane

Dec. 10, 2007

by Brian Mattmiller

Countering a common theory that human evolution has slowed to a crawl or even stopped in modern humans, a new study examining data from an international genomics project describes the past 40,000 years as a time of supercharged evolutionary change, driven by exponential population growth and cultural shifts.

In a study published in the Dec. 10 issue of the Proceedings of the National Academy of Sciences (PNAS), a team led by UW-Madison anthropologist John Hawks estimates that positive selection just in the past 5,000 years alone — around the period of the Stone Age — has occurred at a rate roughly 100 times higher than any other period of human evolution. Many of the new genetic adjustments are occurring around changes in the human diet brought on by the advent of agriculture, and resistance to epidemic diseases that became major killers after the growth of human civilizations.

“In evolutionary terms, cultures that grow slowly are at a disadvantage, but the massive growth of human populations has led to far more genetic mutations,” says Hawks. “And every mutation that is advantageous to people has a chance of being selected and driven toward fixation. What we are catching is an exceptional time.”

Restul il putetzi citi aici. Ia, hai, mai dati-va de aici shi mai facetzi trafic shi la altzii, ca suntetzi prea multzi shi ma ingramaditzi... :)

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