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一场悲剧的落幕,未尝不是另一场喜剧的开始。以白垩纪,躲藏在丛林中的一种小型的爬行动物兽齿类,在失去了恐龙这样一个可怕的天敌之后,得以进一步的发展壮大起来。后来形成的三列齿兽类,也许就是现在哺乳类动物的祖先。与恐龙相比,哺乳动物有着更好的适应力:它身体恒温,可以适应一定的气候变化;它胎生并且有乳腺,后代能够受到更好的照顾;它的大脑较为发达,能够支配自己的行为。这一切都使得,哺乳动物逐渐上升为地球的主人。从现在的化石出土来看,当时就已经出现了种类繁多的哺乳动物,如猫科动物、各种鼠类、猪、牛、羊、马、驴等。还有一科对我们来说十分重要的灵长目,如猴和猿等。实际上在下一个时代,就开始有
The end of a tragedy, is not the beginning of another comedy. In the Cretaceous, hiding in the jungle of a small reptile animal teeth, after losing a terrible dinosaur predators, to be further developed and expanded. The three beetles formed later may be the ancestors of mammals now. Mammals have a much better adaptation than dinosaurs: they are thermostatic and adapt to certain climatic changes; they are viviparous and have mammary glands and their offspring are better cared for; their brains are more developed and able to dominate their behavior . All this makes mammals gradually rise as the owner of the Earth. From the current fossil excavation point of view, there have been a wide range of mammals, such as cats, all kinds of mice, pigs, cattle, sheep, horses, donkeys and so on. There is another section of primate that is very important to us, such as monkeys and apes. In fact, in the next era, it starts to exist