新概念英语优美背诵短文新概念英语漂亮背诵短文 引导语：说起睡觉信任大家都很熟识，那么大家知道睡眠也是有进化的么?下面就让我通过一则新概念英语漂亮短文告知你关于睡眠的进化。 Evolution of Sleep 睡眠的进化 Sleep is very ancient. In the electroencephalographic sense we share it with all the primates and almost all the other mammals and birds: it may extend back as far as the reptiles. 睡眠自古就有。从脑电图上看，我们人类和全部灵长目动物以及几乎全部的哺乳动物和鸟类都一样须要睡眠;甚至爬行类动物也有睡眠。 There is some evidence that the two types of sleep, dreaming and dreamless, depend on the life-style of the animal, and that predators are statistically much more likely to dream than prey, which are in turn much more likely to experience dreamless sleep. In dream sleep, the animal is powerfully immobilized and remarkably unresponsive to external stimuli. Dreamless sleep is much shallower, and we have all witnessed cats or dogs cocking their ears to a sound when apparently fast asleep. 有证据显示，有梦睡眠和无梦睡眠这两种类型的睡眠取决于该动物的生活方式。从统计上看，食肉动物比被捕食动物有更多的有梦睡眠，而被捕食动物更多地无梦睡眠。动物在有梦睡眠时，被有效地解除动作实力，并且对外界刺激缺乏反应。无梦睡眠则要浅得多。我们都看到过猫和狗在明显的酣睡中，有一点响动耳朵就会竖起来。 The fact that deep dream sleep is rare among prey today seems clearly to be a product of natural selection, and it makes sense that today, when sleep is highly evolved, the stupid animals are less frequently immobilized by deep sleep than the smart ones. But why should they sleep deeply at all? Why should a state of such deep immobilization ever have evolved? Perhaps one useful hint about the original function of sleep is to be found in the fact that dolphins and whales and aquatic mammals in genera...
