Thursday, December 27, 2007

Is Cooking the Key to Human Evolution?

“Our hominid ancestors could never have eaten enough raw food to support our large, calorie-hungry brains,” according to a new feature at Scientific American. The column looks at biologist Richard Wrangham’s theory that cooking -- which allowed creatures to consume more energy-dense, softer food -- spurred human evolution.

The theory easily explains why we have smaller stomachs, less menacing teeth and larger brains than our tree-swinging cousins. Brain tissue requires a lot of energy, 22-times as much as skeletal muscle tissue.

The problem with this theory is the timing. Wrangham’s theory requires one tricky ingredient: fire. For the theory to work, Homo erectus would have had to be cooking, with fire, 1.6 to 1.9 million years ago. But there’s little evidence that human ancestors were cooking more than 500,000 years ago.

So how could human brains evolve? Some scientist suggest early hominids ate “energy-dense animal-derived foods” like bone marrow and brain tissue to fuel their own growing brains. Brains to grow brains? It’s macabre, but it makes sense.

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I started pound360 to channel my obsession with vitamins, running and the five senses. Eventually, I got bored focusing on all that stuff, so I came back from a one month hiatus in May of 2007 (one year after launching Pound360) and broadened my mumblings here to include all science.