ホモ属の顔の特徴はselectionにより形作られたのではないかもしれない

今日も髪型のことを余り考えないようにして暮らすわけだが。

http://sciencenow.sciencemag.org/cgi/content/full/2004/1213/3

肝のところは、

Their analyses suggest that natural selection probably crafted australopith features such as big bones and a crested skull that may have anchored strong cheek muscles for chewing. But the scattershot pattern of variation among facial features within the genus Homo suggests that genetic drift played more of a role than natural selection, they report online this week in the Proceedings of the National Academy of Sciences.

で、獲物を切り刻んだり料理したりすることがアウストラロピテクスにかかっていた洗濯圧（atokのバカ）を弱めたという。

Technological advances such as chopping and cooking may have lessened selection pressure on the face, says Cheverud. That makes sense to anthropological geneticist Charles Rosemann of Stanford University. At one time, he says, facial features such as the condition of the teeth would have played a large role in determining an individual's overall vigor. But that may have changed with the advent of tools--which happened roughly when the genus Homo arose. "If you are preprocessing food with stone tools, some features may become functionally unimportant," he says.