Humans are remarkably fuel-efficient, or at least, our brains are. The lump of tissue inside our skulls is three times larger than that of a chimp, and it needs a lot more energy to run. But for our size, we burn about as much energy as a chimp. We’re no gas-guzzlers, so how did we compensate for the high energy demands of our brains? In 1995, Leslie Aiello and Peter Wheeler proposed an answer – we sacrificed guts for smarts.
The duo suggested that during our evolution, there was a trade-off between the sizes of two energetically expensive organs: our guts and our brain. We moved towards a more energy-rich diet of meat and tubers, and we took a lot of the digestive work away from our bowels by cooking our food before eating it. Our guts can afford to be much smaller than expected for a mammal of our size, and the energy freed up by these shrunken bowels can power our mighty brains.
This attractive and intuitive idea – the so-called “expensive tissue hypothesis” became a popular one. Bu tAna Navarrete from the University of Zurich thinks she has disproved it.(… read more)
Links for all things pertaining to human evolution, the Pleistocene, Pliocene, sometimes Miocene, cognitive science, genetics, and other rad stuff.
Wednesday, November 9, 2011
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