SSS 2011-08-22（在线收听） |
Most large animals have to chew food extensively and form it into a mushy ball that's easy to swallow. Cooking makes a huge difference—it softens the food and dramatically reduces eating time. Researchers calculated that if we lived like our non-cooking primate cousins, we'd spend about 48 percent of the day eating. But modern humans spend only about 5 percent of the day chowing down. When our ancestors invented cooking, it gave them a major survival advantage. So how long ago did our forebears start barbecuing?
The softer food available via cooking allowed for the evolution of smaller molars and a smaller jaw. Researchers therefore compared the molars and body sizes of extinct hominids with modern humans and other primates. Turns out that Homo erectus and Neanderthals had, and modern humans have, molars that are smaller than would be predicted by looking at general primate evolution. The finding is in the Proceedings of the National Academy of Sciences.
Based on the appearance of the smaller eating apparatus, the researchers infer that humanity discovered the benefits of cooking about 1.9 million years ago. And we've been enjoying the convenience, speed and taste benefits ever since.
Thanks for the minute. For Scientific American's 60-Second Science, I'm Cynthia Graber. |
| 原文地址：http://www.tingroom.com/lesson/sasss/2011/8/155333.html |