章节大纲

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  • 中生代生命史

    A digital rendering of a feathered dinosaur running, highlighting characteristics of Mesozoic life.
     

    Would Mesozoic Earth look familiar?
    ::间歇性地球看起来熟悉吗?

    The Precambrian and Paleozoic Earth would probably not be recognizable. How about if you visited the Mesozoic? The  planet  would look a lot more like it does today. Animals would fill the niches you're used to seeing animals fill. But the animals would be mostly reptiles. So things wouldn't be so familiar after all.
    ::Precambrian 和 Paleozoic 地球可能无法识别。 如果您访问Mesozoic 地球, 如何呢? 这个星球会看起来更像今天的地球。 动物会填满你常看到的动物填满的地方。 但是动物大多是爬行动物。 所以事情毕竟不会那么熟悉。

    The Mesozoic Era
    ::中索分时代

    The Paleozoic ended with a  mass extinction . This left lots of  habitats  available for new organisms.  Adaptive radiation  by reptiles filled these habitats. The  Mesozoic Era  was the age of reptiles. The planet was generally warmer than it is now. This  climate  was very good for reptiles.
    ::Paleozoic最终以大规模灭绝结束。 这为新生物留下了许多栖息地。 爬行动物的适应性辐射填充了这些栖息地。 MEsozoic Eraa是爬行动物的时代。 这个星球一般比现在更暖和。 这个气候对爬行动物非常适合爬行动物。

    Reptiles developed  adaptations  for living away from  water . Their thick skin keeps them from drying out. The evolution of the  amniote egg  allowed them to lay their eggs on dry land. The  amniote egg  has a shell and contains all the  nutrients  and water required for the developing embryo ( Figure  ).
    ::爬虫类开发了远离水的适应性,其厚厚的皮肤防止了它们干燥。 羊蛋的进化使他们得以在旱地产卵。 羊蛋有一个壳,含有发育中的胚胎所需的所有养分和水(图 ) 。

    An alligator hatchling emerging from an amniotic egg in a natural setting.
     
    Amniotic egg containing an alligator hatchling.

    Dinosaurs
    ::恐龙

    Earth in the Mesozoic was populated by an enormous diversity of reptiles. Most of the reptiles were dinosaurs. Dinosaurs reigned the planet for 160 million years. They had tremendous numbers and diversity. Some were small and some were very large ( Figure  ). There were herbivorous (plant-eating) and carnivorous (meat-eating) dinosaurs. Some dinosaurs developed protection against  predators , such as  horns , spikes, tail clubs, and shielding  plates .
    ::在中索佐奇,地球上的爬行动物种类繁多,大多数爬行动物是恐龙,恐龙统治地球已有1.6亿年,数量和多样性巨大,有些很小,有些非常大(图)。有食草植物和食食食食食食食食食食食食食食食食食动物的恐龙。有些恐龙发展了对捕食动物的保护,例如角、钉子、尾部俱乐部和护板。

    Species  of dinosaurs filled all the niches that are currently filled by mammals. Most dinosaurs lived on land, but a few, like Spinosaurus, could swim. Other types of reptiles, including plesiosaurs and ichthyosaurs swam in the oceans ( Figure  ). Another related group of reptiles, the pterosaurs, flew the skies. Feathered dinosaurs eventually gave rise to birds.
    ::恐龙的物种填满了目前由哺乳动物填满的所有位置。大多数恐龙生活在陆地上,但少数恐龙,如脊柱龙,可以游泳。其他类型的爬虫类,包括类动物和类动物在海洋中游荡(图 ) 。 另一组相关的爬虫类,即恐龙,在空中飞翔。 羽毛恐龙最终产生鸟类。

    Tyrannosaurus Rex with two Gallimimus in a Mesozoic forest environment.
     
    Some examples of Mesozoic dinosaurs include this Tyrannosaurus Rex, pictured with two Gallimimus.

    Scientists now think that at least some dinosaurs were endothermic (warm-blooded). There is a lot of evidence for this  hypothesis . Some dinosaurs lived in colder regions, and had feathers for  insulation . Many dinosaurs grew fast and were very active. Dinosaur bones had canals, like birds. Some dinosaurs stood upright and had big brains. These features are more typical of endotherms.
    ::科学家现在认为至少有些恐龙是终极热(温血)的。这个假设有许多证据。有些恐龙生活在较寒冷的地区,有羽毛作为绝缘。许多恐龙生长迅速,非常活跃。恐龙骨头有运河,像鸟一样。有些恐龙站立直立,有大大脑。这些特征更典型的是内温。

    Fossil skeleton of a Tyrannosaurus Rex displayed in a museum, alongside other dinosaur fossils.
     
    Plesiosaurs were large marine reptiles that lived in the Mesozoic.

    Plants also did well in the Mesozoic. Lush forests covered the land. Flowering plants evolved later in the Mesozoic.
    ::在梅索索契克岛,植物也很好,Lush森林覆盖了这片土地,后来在梅索索契克岛发展了花卉植物。

    Rise of the Mammals
    ::哺乳动物的崛起

    Mammals appeared near the end of the Triassic. Throughout the Mesozoic, most species of mammals were small and ate insects, but some had more varied diets. After the dinosaurs died out, mammals diversified greatly.
    ::哺乳动物出现在Triassic河尽头附近,在整个中索索奇河中,大多数哺乳动物物种都是小而食用昆虫,但有些哺乳动物的饮食种类更多。 恐龙灭亡后,哺乳动物的种类大不相同。

    Cretaceous Extinction
    ::白鲸白鲸

    The Mesozoic ended in a mass extinction event 66 million years ago. Between the Mesozoic Era and the  Cenozoic Era , about 75% of all species died off. This mass extinction is when the non-avian dinosaurs became  extinct . Most scientists think that the extinction was caused by a giant  meteorite  that struck Earth. The impact created an immense  crater , and heated debris rained back down, causing widespread wildfires. Dust flew into the  atmosphere  and blocked sunlight for a  year  or more. This cooled the Earth and reduced  photosynthesis . Sulfur from the impact mixed with water in the atmosphere. The result was  . The  rain  dissolved the shells of the tiny marine  plankton  that form the base of the  food chain . With little food being produced, animals starved.
    ::美索zoic在6600万年前以大规模灭绝事件告终。 在梅索索契时代和奇诺索契时代之间, 大约75%的物种死亡。 这种大规模灭绝是非禽类恐龙灭绝之时。 大多数科学家认为, 灭绝是由撞击地球的巨型陨石造成的。 撞击造成了巨大的弹坑, 热量碎片又回落, 导致大范围的野火。 灰尘飞入大气层, 遮蔽阳光一年或一年以上。 这让地球冷却, 减少了光合作用。 硫磺与大气中水混合。 结果是: 雨水溶解了构成食物链底部的小型海洋浮游生物的炮弹。 少量食物被生产, 动物饿死了。

    Summary
    ::摘要

    • The amniote egg allowed reptiles to move away from water.
      ::羊膜蛋让爬行动物离开水面
    • In the Mesozoic, dinosaurs filled the niches that mammals fill today.
      ::恐龙填满了哺乳动物今天所填充的缝隙。
    • About half of the life forms of the Mesozoic appear to have gone extinct due to a giant asteroid impact.
      ::由于小行星的撞击,约一半的中索佐奇生物形式似乎已经灭绝。

    Review
    ::回顾

    1. How did life in the Mesozoic resemble life today? How did it differ from life today?
      ::美索索维奇的人生与今天的生活有什么相似之处?它与今天的生活有何不同?
    1. What was the importance of the amniote egg for Mesozoic life?
      ::羊膜蛋对美索zoic生命的意义何在?
    1. How are dinosaurs and modern birds related?
      ::恐龙和现代鸟类之间有什么关系?