Breaking News English Lesson on Human Evolution

Eating habits and food processing skills from two million years ago helped us to evolve and develop language. Researchers say that learning to cut up meat and use stone tools to process food were crucial steps in our evolution. The fact that we cut food up meant we used less time for chewing. This gave us more time to develop language and communicate. The researchers estimate that cutting up food saved early humans as many as 2.5 million chews per year. In contrast, chimpanzees spend half the day chewing, which means they have less time to communicate.

Researchers also say the shape of our face changed because we needed to chew less. Our jaws and teeth became smaller. Professor Daniel Lieberman said: "We went from having…big teeth and large chewing muscles to having smaller teeth [and] smaller chewing muscles. Those changes…allowed for the selection for speech and other shifts in the head, like bigger brains." Dr Lieberman chewed raw meat to test his theory. He said: "You chew and you chew and you chew and you chew, and nothing happens." He said that slicing meat before chewing, "is the simplest technology of all".