Primatologist Cooks Up New Evolution Theory

Richard Wrangham, a primatologist, anthropologist and Harvard professor spent 40 years of his life observing wild chimps in Africa. In May, he will publish the book, "Catching Fire: How Cooking Made Us Human". He has studied wild chimps because he believes their behavior will offer insights into prehistoric humans. He theorizes that cooking food and using fire were the main driving force behind the evolution from ape to human. For years, scientists have argued that tool making and meat eating are what facilitated human evolution. Wrangham agrees that these adaptations were key, however he argues that our large brain and body shape are the direct result of a diet that was only available to us after we started cooking our food. The chimps he's observed in the wild mostly sustain on a diet of extremely fibrous materials that must be chewed for hours. Once our early ancestors began cooking food about 1.8 million years ago, their diets became softer, more nutritious, calorie-rich, and less time-consuming. His theory also includes that once communal cooking fires were established, humans spent more time around them, allowing for social evolution and communication.

Wrangham's biggest criticism is of his lack of evidence, mainly, archeological proof of fire places as old as 1.8 million years. He cites the evidence of controlled fire 800,000 years ago in Israel, as well as ancient meat preparing tools of our distant ancestor Homo habilis. His theory relies mostly on the biological evidence, including smaller teeth and guts starting 1.8 million years ago, as well as the leaner, more human like bodies of Homo erectus.

As for humans today, Wrangham believes that our bodies have adapted to modern food by becoming even better at maximizing the energy we get from our diet. However, we take in more than we need, which is not adaptive.

Update:
Another bit of biological evidence Wrangham uses to support his claim is the sexual dimorphism of males and females through evolution. Homo erectus males were about the same size as their ausralopithicine ancestors, but the female H. erectus is 60 percent taller and heavier than her predecessor, this difference being comparable to a modern 10 year old girl and an adult woman. Wrangham attributes the change to a diet of cooked food. Females were able to eat enough to get bigger, and bigger generally means more fecund.
As a result of the smaller sexual dimorphism of Homo erectus, Wrangham suggests that males were no longer under pressure to get bigger themselves. Wrangham believes that this slight decline of male competition brought about the origins of distinctly human pair bonding.
Wrangham's claims continue to receive criticism, but it certainly is food for thought.

-Jane de Verges, Group B