The introduction of the raw meat in the diet and use instruments basic stone could explain the evolution of traits of smaller chewing in hominids, as published today the British journal “Nature”.
the study suggests that meat and instruments Paleolithic, and not the subsequent arrival of the kitchen, would have allowed the reduction of the size of features related to the act of chewing, as a smaller face and teeth.
This selection process also could allow other functions such as speech enhancement and thermoregulation.
At the time of Homo erectus (two million years ago), humans had developed brains and bodies requiring larger reserves of daily energy.
Paradoxically, also smaller teeth, masticatory muscles and weaker jaws formed and intestines smaller than in previous species.
This research suggests that these changes were made possible by the incorporation of more meat in the diet, food processing using stone tools, or cooking food, although this practice was not common until 500,000 years ago.
Daniel Lieberman and Katherine Zink, of Harvard University, assessed how the techniques of food processing Lower Paleolithic affect the strength of mastication .
to do this, fed adult subjects with standardized samples of meat (goat) and storage organs rich plant starch (potatoes, carrots and beets).
they measured the muscular effort required to chew and how the food is cut up before swallowing.
they found that, following a composite of one-third of meat diet and chop the flesh and crushing plants with stone tools before ingesting, primitive man would have needed 17% less often and 26% less energy in chewing.
the scientists concluded that this reduction effort to chew produced a transformation in the muscles of the face used for this movement. EFE
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