GWD32 32-34 终结版（TN答案有错）

Teresayang

谢谢喽！全对啦！怎么答案会错？

谢谢楼主大帅哥

lupisces

agree

C  explaining the mechanisms through which marine life-forms evolved during a particular period  文章没说怎么进化的，只是说哪些factor促进了进化 （external events）

不对

hairicanye

真的是~~~

jasonleo

我也选得是BBE

caopp

实在是太感谢了，楼主真是解我燃眉之急啊

jackieli007

~~

alibaba_2009

up

alibaba_2009

以下是引用kevintown在2008/8/11 2:46:00的发言：

1.        GWD32—32-34 奥陶纪海洋生物进化
   Ordovician marine life evolution

The dry mountain ranges of the western United States contain rocks dating back 440 to 510 million years, to the Ordovician period, and teeming with evidence of tropical marine life. This rock record provides clues about one of the most significant radiations (periods when existing life-forms gave rise to variations that would eventually evolve into entirely new species) in the history of marine invertebrates. During this radiation the number of marine biological families increased greatly, and these families included species  that would dominate the marine ecosystems of the area for the next 215 million years. Although the radiation spanned tens of millions of years, major changes in many species occurred  during a geologically short time span within the radiation and, furthermore, appear to have occurred worldwide, suggesting that external events were major factors in the radiation. And , in fact, there is evidence of major ecological and geological changes during this period: the sea level dropped drastically and mountain ranges were formed, in this instance, rather than leading to large-scale extinctions, these kinds of environmental changes may have resulted in an enriched pattern of habitats and nutrients, which in turn gave rise to the Ordovician radiation. However, the actual relationship between these environmental factors and the diversification of life forms is not yet fully understood.

radiation.适应性进化

 

 

第一句提出西部干旱山脉充分提供了奥陶纪热带海洋生物的证据。这些石头提供了海洋无脊椎动物史上最重要的适应性进化线索。这段期间，海洋生物大量增加，这些新进化的种族统治了以后215m年的海洋生态系统。尽管这段进化期跨越了1千万年，重大物种进化是在此期间很短时间内发生的，而且是全球性的，说明外在事件是最大影响因素。而且有证据证明：海平面大幅下降，山脉形成，这样，不仅没有大规模物种灭绝，反而丰富了栖息环境和饮食营养，反过来促进了奥陶纪生物进化。尽管如此，这些生态环境因素和物种的多样性的关系还没被完全了解。

 

 

文章讨论中心是：奥陶纪
  海洋生物
  的进化，  主题是：推测是由环境因素导致进化

 

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Q5. Which of the following can be inferred from the passage regarding the geologic changes that occurred during Ordovician period?

A.        They were more drastic than those associated with other radiations

B.         They may have created conditions favorable to the evolution of many new life-forms

正确，these kinds of environmental changes may have resulted in an enriched pattern of habitats and nutrients, which in turn gave rise to the Ordovician radiation.

C.        They may have caused the extinction of many of the marine species living in shallow waters

D.        They may have been a factor in the development of new species adapted to living both on land and in water 海洋两栖动物没有提到，只说了海洋无脊椎动物和海洋生物

E.         They hastened the formation of the extensive dry regions found in the western united states

更本没有提到，原文只说了美国西部的Dry Mountain

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 in turn gave rise to the Ordovician radiation说明是进一部产生radiation。另外主要的物种变化是在整个radiation起间一小段，是由于海和山的变化导致的。The dry mountain ranges of the western United States 说明了E对。

alibaba_2009

up

cdinitialb

文中只提到了那个山，并没有提到geological changes和山的形成的关系。 ls估计是想既然山上有石头提供radiation的线索，所以地形的改变可能导致山的形成。这个推论过于“狂野”了。