章节大纲

  • 常规

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  • 显生宙的生命

    Horseshoe crab on sand alongside a fossilized horseshoe crab imprinted in rock.

     

    Does this look like a creature from Earth you know?
    ::这看起来像地球上的生物吗?

    It's not hard to take a  field trip  to see some ancient life. Horseshoe crabs live along the east coast of the United States and elsewhere. These ancient creatures have been more-or-less unchanged for the past 450 million years. This is indicated by  fossils . That doesn't get them quite back to the beginning of the Paleozoic but close. So hundreds of millions of generations of horseshoe crabs have seen most of the Phanerozoic go by.
    ::观察一些古代生物并不难。 马蹄蟹生活在美国东海岸和其他地方。 这些古代生物在过去的4.5亿年中基本没有变化。 化石表明了这一点。 这并不能让他们回到Paleozoic的开始, 但却是接近的。 因此数亿代的马蹄蟹已经看到大部分的Phanerozoic动物经过。

    Phanerozoic Eon
    ::法新甲醚Eon

    The  Phanerozoic Eon  is divided into three eras—the  Paleozoic , the  Mesozoic , and the  Cenozoic  ( Figure  彩蛋. They span from about 540 million years ago to the present. We live now in the  Cenozoic Era .
    ::Phanerozoic Eon被分为三个时代——Paleozoic、Mesozoic和Cenozoic(Figure () ) , 从5亿4千万年前到现在,我们现在生活在Cenozoic时代。

    Earth’s  climate  changed numerous times during the Phanerozoic Eon. At the end of the Precambrian, much of the  planet  was covered with  . At the start of the Phanerozoic Eon, the climate became warm and humid. Since then Earth’s climate has gone through four cycles of frigid glaciers and warm tropical seas. Some organisms survive changes in the climate. Others go  extinct  when the climate changes too much.
    ::在Phanerozoic Eon 期间,地球的气候发生了无数次变化。 在Precambrian的尽头,地球大部分被覆盖。 在Phanerozoic Eon的一开始,气候就变得温暖和潮湿。 从那时起,地球的气候经历了四轮冰冷的冰川和温暖的热带海洋。有些生物在气候变化中幸存下来。 另一些生物在气候变化过大时灭绝。

    Phanerozoic Time Line
    ::夏内分泌时间线

    Table    shows some of the life forms that developed during the Phanerozoic Eon. Life gradually became more diverse and new  species  appeared. Most modern organisms evolved from species that are now extinct.
    ::表格显示了在Phanerozoic Eon期间形成的一些生命形式。生命逐渐变得更加多样化,出现了新的物种。大多数现代生物从现已灭绝的物种中演变而来。

    Era Millions of Years Ago Major Forms of Life
    Cenozoic 0.2 (200,000 years ago) First humans
      35 First grasses; grasslands begin to dominate the land
    Mesozoic 130 First plants with flowers
      150 First birds on Earth
      200 First mammals on Earth
      251

    Age of dinosaurs begins
    ::恐龙开始的时代

    A dinosaur standing on rocks, representing the Age of Dinosaurs in the Phanerozoic Eon.

     
    Paleozoic 300 First reptiles on Earth
      360 First amphibians on Earth
      400 First insects on Earth
      475 First plants and fungi begin growing on land
      500

    First fish on Earth
    ::地球上第一鱼

    The first fish on Earth during the Phanerozoic Eon.

     


     

    Summary
    ::摘要

    • The Phanerozoic has spanned from 540 million years ago to present.
      ::夏内罗zoic 已经从5亿4千万年前 一直到现在。
    • The Phanerozoic Eon is made up of the Paleozoic, Mesozoic, and Cenozoic Eras.
      ::Phanerozoic Eon由Paleozoic、Mesozoic和Cenozoic Eras组成。
    • The quantity and diversity of life has exploded since the beginning of the Phanerozoic.
      ::自Phanerozoic开始以来,生命的数量和多样性已经爆炸。

    Review
    ::回顾

    1. When did the Phanerozoic begin? When did it end?
      ::从什么时候开始的 什么时候结束的
    1. What are some of the major events that have occurred in the Phanerozoic?
      ::在Phanerozoic发生的一些重大事件是什么?
    1. What eras make up the Phanerozoic?
      ::什么时代组成了Phanerozoic?