英语听力文摘 谁进化得更好
About six or seven million years ago chimpanzees and humans evolved from a common primate ancestor.
Chimps went on to become the relatively small-brained, forest dwelling creatures we know and love. Humans went on to evolve large brains, spread throughout the world, and eventually build the internet.
So surely this must mean that humans are more highly "evolved" than chimps, right?
Not so fast. A study comparing the human and chimp genome has found that, genetically speaking, chimps are more highly evolved than humans. Since emerging from that common ancestor, 233 chimp genes have evolved adaptively. Humans? We're way behind at only 154 adaptively evolved genes since we came on the scene.
So why have so many more chimp genes undergone change? One reason may be that until fairly recently, there were a lot more chimps on earth than humans. So there was a bigger chimp gene pool and more opportunity for random mutations and natural selection. It's also possible that chimps have had to adapt more than humans to different terrains, climates, and other things.
What's clear is that more genetic change, or being more highly evolved, doesn't necessarily mean being brainier. Chimps' advanced rate of evolution hasn't resulted in human-sized brains or tool-making ability rivaling that of humans.
Nevertheless, the study is a sharp reminder that, like chimps, humans are animals. Over time, maybe our rate of genetic change will catch up to that of our chimp cousins.
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