托福阅读题目解析：生态系统的长期稳定

　　9. In paragraph 5, why does the author provide the information that “(A fifteen-speed racing bicycle is more likely to break down than a child’s tricycle)”?

　　○To illustrate a general principle about the stability of systems by using an everyday example

　　○To demonstrate that an understanding of stability in ecosystems can be applied to help understand stability in other situations

　　○To make a comparison that supports the claim that, in general, stability increases with diversity

　　○To provide an example that contradicts mathematical models of ecosystems

　　Paragraph 6: Ecologists are especially interested to know what factors contribute to the resilience of communities because climax communities all over the world are being severely damaged or destroyed by human activities. The destruction caused by the volcanic explosion of Mount St. Helens, in the northwestern United States, for example, pales in comparison to the destruction caused by humans. We need to know what aspects of a community are most important to the community’s resistance to destruction, as well as its recovery.

　　10. The word “pales” in the passage is closest in meaning to

　　○Increases proportionally

　　○Differs

　　○Loses significance

　　○Is common

　　Paragraph 7：Many ecologists now think that the relative long-term stability of climax communities comes not from diversity but from the “patchiness” of the environment, an environment that varies from place to place supports more kinds of organisms than an environment that is uniform. A local population that goes extinct is quickly replaced by immigrants from an adjacent community. Even if the new population is of a different species, it can approximately fill the niche vacated by the extinct population and keep the food web intact.

　　11.Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incurred choices change the meaning in important ways or leave out essential information.

　　○Ecologists now think that the stability of an environment is a result of diversity rather than patchiness.

　　○Patchy environments that vary from place to place do not often have high species diversity.

　　○Uniform environments cannot be climax communities because they do not support as many types of organisms as patchy environments.

　　○A patchy environment is thought to increase stability because it is able to support a wide variety of organisms.

　　12.The word “adjacent” in the passage is closest in meaning to

　　○Foreign

　　○Stable

　　○Fluid

　　○Neighboring

　　Paragraph 6: Ecologists are especially interested to know what factors contribute to the resilience of communities because climax communities all over the world are being severely damaged or destroyed by human activities. The destruction caused by the volcanic explosion of Mount St. Helens, in the northwestern United States, for example, pales in comparison to the destruction caused by humans. We need to know what aspects of a community are most important to the community’s resistance to destruction, as well as its recovery.

　　13.Look at the four squares [ ] that indicate where the following sentence could be added to the passage.

　　In fact, damage to the environment by humans is often much more severe than damage by natural events and processes.

　　Where would the sentence best fit? Click on a square to add the sentence to the passage.

　　14.Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points.

　　The process of succession and the stability of a climax community can change over time.

　　Answer choices

　　○The changes that occur in an ecosystem from the pioneer to the climax community can be seen in one human generation.

　　○A high degree of species diversity does not always result in a stable ecosystem.

　　○The level of resilience in a plant community contributes to its long-term stability.

　　○Ecologists agree that climax communities are the most stable types of ecosystems.

　　○Disagreements over the meaning of the term “stability” make it difficult to identify the most stable ecosystems.

　　○The resilience of climax communities makes them resistant to destruction caused by humans.

　　托福阅读题目参考答案：

　　1. ○3　　2. ○3　　3. ○1　　4. ○2　　5. ○3　　6. ○2　　7. ○3　　8. ○2　　9. ○1　　10. ○3　　11. ○4　　12. ○4　　13. ○2　　14. ○2 3 5