2014托福阅读听力真题汇总

1、講了 Kelp和講了 Kelp和urchin數量關係(說講這兩種數量關係的目的是？）Kelp越來越少了，大家就懷疑是urchin 的錯。然後就提出Assumption啊，說Urchin的increase會導致kelp的decrease。可是又說，這種 assumption不對，因為kelp可能是受了 XX和厄爾尼諾的影響，跟Urchin不關係。第二和第三段分別舉了兩個例子，大概的意思是證明kelp的decrease不是因為Urchin的錯（有題，問 二三段的關係），有可能是因為什麼病的影響而導致kelp的減少。不過，因為Urchin的increase而導致kelp decrease的例子是有的

2、，然後就舉了兩個support的例子。 就說了 otter、lobster(會吃Urchin的東東）多的時候，kelp也會多，因為otter和lobster會吃了 Urchin，U減少，K就自然增加。單字：contention: claim ; whereasThe harmony present in any ecological system relies on the inclusion of different types of species, each with a specific role or set of roles. Although to some extent all

3、 species contribute in important ways, scientists are now learning about the pivotal parts played by, what are being called foundational and keystone species. Interestingly, the latter represent only a small fraction of the overall animal population within an ecosystem while the former can make up a

4、 significant portion of it. In both cases, though, their removal often results in massive changes to, if not the complete destruction of, their ecosystems. Efforts to conserve these species are currently based on the new idea that they prevent the start of a domino effect that would, once started, b

5、e unstoppable.Foundational species are the backbones of the systems they inhabit. These species are referred to as primary producers, which means that they generate a large amount of the abundance other species require to survive. In most cases, they are a type of vegetation or stationary animal. Co

6、ral, which tends to grow in large colonies, is often pointed to as an example. Eventually a group of colonies will form a coral reef, which can sustain a complete ecosystem around it. The reef contains the skeletal remains of coral at its bottom and living coral on the top. Numerous animals, includi

7、ng zooplankton and sponges, live in the small crevices located in the rock-like bottom. At the top, the coral interacts with seaweed and other forms of vegetation to regulate the levels of nutrients and gases in the water. There are also more than four thousand types of fish that live on or around m

8、ost coral reefs. Fish rely on the holes in the reef for protection. The more colorful species of coral provide excellent camouflage for fish, as well. Obviously, without its foundational species, an ecosystem would collapse.Keystone species play less apparent but equally important roles. The name co

9、mes from the keystones used in the building of stone archways. The keystone receives the smallest amount of pressure of all the stones in the arch, but, if it is removed, the arch will collapse. In the same way, research is now showing, certain species within ecosystems, although they are smaller in

10、 numbers and biomass than most of the other species present, act like keystones.These species are being categorized as either predators or engineers, depending on their relationships with the various species around them. These categories are not absolute, though, and animals are moved from one to th

11、e other as new facts come to light.In the case of predator keystone species, there are four carnivores that prey on herbivores and other animals. Also, the herbivores usually have no other natural predator in the ecosystem. The sea otter is now considered by many scientists to be a keystone species,

12、 because it controls the number of sea urchins, which have few other predators. Both species can be found around kelp forests, which are in the warm parts of the worlds oceans. Because kelp is an underwater plant, its roots are not used for the collection of nutrients. Instead, they are there to anc

13、hor the plant. As soon as enough sea urchins chewed on the roots, which are fragile, the kelp would be removed from the ecosystem. If the sea otter were to disappear, the urchins would quickly grow in number and destroy all the kelp. Engineer keystone species maintain the balance in ecosystems in di

14、fferent ways. Although bears tend to live in forests, they bring in important sources of nutrients from ocean and sea-based ecosystems. The bears capture large salmon from the water and take them into the forest to eat them. This distributes large amounts of protein in the form of bear waste matter

15、as well as uneaten portions of salmon. The protein eventually supports life in the forest, either as a food source for smaller animals or the vegetation. Another species that plays a part similar to that of bears is the beaver. Through the construction of dams, beavers convert small rivers into pond

16、s and marshes. The new landscape in turn supports a variety of fish, which in turn provides a dependable source of food for the beavers. The removal of beavers from an ecosystem would also remove the landscape it depends on.The word extent in the passage is closest in meaning toamountexplanationpurp

17、oseaverageAccording to paragraph 1, foundational species are usuallyresponsible for environmental damagepresent only in certain ecosystemsclose to complete extinctionfound in the largest numberThe word sustain in the passage could best be replaced byendurecreatereceivesupportThe word it in the passa

18、ge refers tocoralcoral reefecosystemcolonyWhich of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.The foundational species become obvious once the syste

19、m has collapsed.Ecosystems will not collapse as the foundational species do not exist.It is clear that the system would fall apart if it did not have its foundational species.Without the collapse, the foundational species are not obvious in the ecosystem.The author mentions arches in paragraph 3 in

20、order tohelp understand what keystone species meansprovide an example of an ecological imbalanceshow the problems with a foundational speciesexplain the role of a type of animal speciesWhich of the following can be inferred from paragraph 3 about keystone species?Their roles have been understood for

21、 a long time.They are related to a large number of ecosystems.They are now seen as less important in nature.They are the subjects of ongoing research.The phrase In the same way in the passage could best be replaced bysimilarlyusuallyconverselystronglyIt is NOT true according to paragraph 4 that sea

22、ottershunt sea urchinsdamage kelp rootseat keystone specieslive near waterAccording to paragraph 5, which of the following is true about beavers?They are predator keystone species.They live in the same areas as bears.They usually eat fish from ponds.They can create large, strong dams.Look at the four squares that indicate where the follo