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①2014-5-17CN Habitat Selection（栖息地选择）

Researchers who study habitat selection have proposed various models for the process. Marine biologist Peter F. Sale hypothesized the existence of a simple mechanism of habitat selection in fish that is based on levels of exploratory behavior. Sense organs monitor specific stimuli in the environment and send a summation of pertinent stimuli back to central-nervous-system centers, which regulate the amount of exploration. As the constellation of cues approaches some optimum level, exploratory behavior ceases and the animal stays where it is.

An alternative hypothesis is that an animal has a cognitive map of the ideal habitat and that its behavior is goal directed. However, working with a species of surgeonfish, Sale tested juveniles in laboratory tanks with various water depths and bottom covers under which fish could hide. Exploration time was least in the tank with shallow water and bottom covers and highest in the tank with shallow water and no bottom cover. In choice tests and field observations, most fish preferred shallow areas with bottom cover. Thus, Sale concluded, there is no need to suggest the inheritance of complex cognitive maps and goal-directed behaviors, rather, the animal simply moves around more in an unsuitable habitat and less in a suitable one.

Sale’s model still does not explain how the animal “knows” what is suitable and what is not, or how stimuli from multiple cues are integrated. Nor does it explain the role of photoperiod (the duration  of  the  animal’s  daily  exposure  to  sunlight)  in  the  response  of  dark-eyed  juncos  to photographs of their natural habitat. These wild-caught birds were presented a choice of viewing one of two 35-millimeter color slides showing different habitats. Birds kept in the lab under a winter photoperiod of nine hours of light and fifteen hours of darkness preferred (spent more time in front of) slides of their southern winter habitat. After day length was increased to fifteen hours of light and nine hours of darkness, the birds’ viewing preferences shifted to the northern summer habitat.

Social cues may also affect choice of habitat. Large juncos (usually males) dominate smaller individuals (usually females and juveniles) in wintering flocks. Biologist Ellen Ketterson explained the finding that females usually migrate farther south than males by hypothesizing that subordinate birds are forced to migrate farther to avoid competing with dominants. In their lab study, researchers E. Roberts and Peter Weigl found that during the short days (stimulating winter), small subordinate juncos showed the strongest preference for winter scenes.

Risk of predation and competition are other factors that may affect habitat use. Hairy-footed gerbils live in vegetated islands in a sea of sand in the Namib Desert of southern Africa. Habitat use was determined by tracks in the sand and by how quickly they gave up feeding at stations containing seeds mixed with sand. Gerbils preferred sites around bushes or grass clumps to open areas and were more active on new-Moon nights than on full-Moon nights. They also gave up feeding at seed trays sooner in open areas and on full-Moon nights. These differences were likely caused by greater risk of predation in open areas and when the Moon was full. When striped mice, a close competitor of the gerbil, were removed, gerbils increased foraging activity, especially in the grass clumps.

The immediate cues to which animals respond when selecting a habitat may not be the same as the ultimate factors that have brought about the evolution of the response. For example, the blue tit, a European bird, lives in oak woodlands where most of its preferred food is found. But the blue tit establishes its territory each year before leaves and caterpillars (its staple food) have even appeared, so it must be using some other cue, such as the shape of the trees, to select its habitat. In fact, we know little about the signals that animals respond to when choosing their habitat. And in migratory species, it is not even clear when in the life cycle a choice of habitat is made. One study found that breeding sites may be selected in late summer or fall before migration, rather than in the spring, as is usually assumed.

Paragraph 1

Researchers who study habitat selection have proposed various models for the process. Marine biologist Peter F. Sale hypothesized the existence of a simple mechanism of habitat selection in fish that is based on levels of exploratory behavior. Sense organs monitor specific stimuli in the environment and send a summation of pertinent stimuli back to central-nervous-system centers, which regulate the amount of exploration. As the constellation of cues approaches some optimum level, exploratory behavior ceases and the animal stays where it is.

1.   The word “pertinent” in the passage is closet in meaning to

A.   important

B.   selected

C.   strong

D.   relevant

2.   According to paragraph 1, all of the following are processes that occur during exploratory behavior EXCEPT:

A.   A favorable combination of cues are gathered.

B.   Sense organs detect and record stimuli in the surrounding area.

C.   Sense organs receive further directions from the central nervous system.

D.   The central nervous system receives a summary of stimuli from the sense organs.

3.   The word “ceases” in the passage is closet in meaning to

A.   stops

B.   decreases

C.   succeeds

D.   occurs Paragraph 2

An alternative hypothesis is that an animal has a cognitive map of the ideal habitat and that its behavior is goal directed. However, working with a species of surgeonfish, Sale tested juveniles in laboratory tanks with various water depths and bottom covers under which fish could hide. Exploration time was least in the tank with shallow water and bottom covers and highest in the tank with shallow water and no bottom cover. In choice tests and field observations, most fish preferred shallow areas with bottom cover. Thus, Sale concluded, there is no need to suggest the inheritance of complex cognitive maps and goal-directed behaviors, rather, the animal simply moves around more in an unsuitable habitat and less in a suitable one.

4. In paragraph 2, why does the author discuss Sale’s research with a species of surgeonfish?

A.   To demonstrate how animals distinguish suitable habitats from unsuitable ones

B.   To give an example of an animal that shows little or no exploratory behavior during habitat selection

C.   To challenge the hypothesis that animals have complex cognitive maps of their ideal habitat that guides their habitat selection

D.   To provide evidence that fish prefer areas that are shallow and have covering under which to hide.

Paragraph 3

Sale’s model still does not explain how the animal “knows” what is suitable and what is not, or how stimuli from multiple cues are integrated. Nor does it explain the role of photoperiod (the duration  of  the  animal’s  daily  exposure  to  sunlight)  in  the  response  of  dark-eyed  juncos  to photographs of their natural habitat. These wild-caught birds were presented a choice of viewing one of two 35-millimeter color slides showing different habitats. Birds kept in the lab under a winter photoperiod of nine hours of light and fifteen hours of darkness preferred (spent more time in front of) slides of their southern winter habitat. After day length was increased to fifteen hours of light and nine hours of darkness, the birds’ viewing preferences shifted to the northern summer habitat.

5.   The word “integrated” in the passage is closet in meaning to

A.   interpreted

B.   produced

C.   found

D.   combined

6.   According  to  paragraph  3,  Sale’s  model  of  habitat  selection  is  unable  to  explain  which  of  the following?

A.   Why dark-eyed juncos’ interest in a particular habitat changes with the duration of daylight they are exposed to

B.   Why the environment suitable for dark-eyed juncos in the winter differs from the environment suitable for them in the summer

C.   Why only some species of animals respond to photographs of their natural habitats

D.   Why birds studied in the lab behave differently than birds in the wild do

7.   Paragraph 3 supports which of the following statements about dark-eyed juncos?

A.   The habitat preference of dark-eyed juncos changes with the amount of daylight present.

B.   Wild-caught dark-eyed juncos do not recognize photographs of their own habitat.

C.   Dark-eyed juncos choose their habitat based on seasonal temperatures.

D.   Artificial light affects dark-eyed juncos’ choice of habitat differently than does natural sunlight. Paragraph 4

Social cues may also affect choice of habitat. Large juncos (usually males) dominate smaller individuals (usually females and juveniles) in wintering flocks. Biologist Ellen Ketterson explained the finding that females usually migrate farther south than males by hypothesizing that subordinate birds are forced to migrate farther to avoid competing with dominants. In their lab study, researchers E. Roberts andPeter Weig found that during the short days (stimulating winter), small subordinate juncos showed the strongest preference for winter scenes.

8.   According to paragraph 4, what reason has been suggested for why female juncos often migrate farther south than do male juncos?

A.   To avoid the colder temperatures farther north

B.   To provide safer habitats for their juveniles

C.   To avoid having to compete with males

D.   To find habitats having the longest days Paragraph 5

Risk of predation and competition are other factors that may affect habitat use. Hairy-footed gerbils live in vegetated islands in a sea of sand in the Namib Desert of southern Africa. Habitat use was determined by tracks in the sand and by how quickly they gave up feeding at stations containing seeds mixed with sand. Gerbils preferred sites around bushes or grass clumps to open areas and were more active on new-Moon nights than on full-Moon nights. They also gave up feeding at seed trays sooner in open areas and on full-Moon nights. These differences were likely caused by greater risk of predation in open areas and when the Moon was full. When striped mice, a close competitor of the gerbil, were removed, gerbils increased foraging activity, especially in the grass clumps.

9.   According to paragraph 5, why do hairy-footed gerbils prefer to feed in bushes and grass clumps?

A.   There is more food available there.

B.   There is less competition there from striped mice.

C.   There is more shade there from the heat of the desert.

D.   There is less danger there of being harmed by a predator.

Paragraph 6

The immediate cues to which animals respond when selecting a habitat may not be the same as the ultimate factors that have brought about the evolution of the response. For example, the blue tit, a European bird, lives in oak woodlands where most of its preferred food is found. But the blue tit establishes its territory each year before leaves and caterpillars (its staple food) have even appeared, so it must be using some other cue, such as the shape of the trees, to select its habitat. In fact, we know little about the signals that animals respond to when choosing their habitat. And in migratory species, it is not even clear when in the life cycle a choice of habitat is made. One study found that breeding sites may be selected in late summer or fall before migration, rather than in the spring, as is usually assumed.

10. According to paragraph 6, which of the following is true about habitat selection by the blue tit?

A.   It selects a habitat having the tallest trees.

B.   It selects a habitat where there are no caterpillars to eat the leaves.

C.   It selects its territory each year in spring.

D.   It selects its habitat before its preferred food appears in the area.

11. Paragraph 6 supports which of the following statements about scientists’ knowledge of habitat selection?

A.   Scientists have successfully identified most of the immediate factors that animals respond to in choosing their habitats.

B.  Scientists have determined the seasons in which most animal species choose their habitats.

C.   Scientists know that evolution has led animals to ignore cues in their environment when choosing habitats.

D.   Scientists still have much to learn about the cues to which animals respond in choosing their habitats.

Paragraphs 3 and 4

Sale’s model still does not explain how the animal “knows” what is suitable and what is not, or how stimuli from multiple cues are integrated. Nor does it explain the role of photoperiod (the duration  of  the  animal’s  daily  exposure  to  sunlight)  in  the  response  of  dark-eyed  juncos  to photographs of their natural habitat. These wild-caught birds were presented a choice of viewing one of two 35-millimeter color slides showing different habitats. Birds kept in the lab under a winter photoperiod of nine hours of light and fifteen hours of darkness preferred (spent more time in front of) slides of their southern winter habitat. ■After day length was increased to fifteen hours of light and nine hours of darkness, the birds’ viewing preferences shifted to the northern summer habitat.

■    Social cues may also affect choice of habitat. ■Large juncos (usually males) dominate smaller individuals (usually females and juveniles) in wintering flocks. ■Biologist Ellen Ketterson explained the finding that females usually migrate farther south than males by hypothesizing that subordinate birds are forced to migrate farther to avoid competing with dominants. In their lab study, researchers

E.   Roberts and Peter Weigl found that during the short days (stimulating winter), small subordinate juncos showed the strongest preference for winter scenes.

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

However, photoperiod is not the only factor in the habitat selection of this bird species. Where would the sentence best fit? Click on a square [■] to add the sentence to the passage.

参考答案：

1-5：DCACD

6-10：AACDD

11-12：D B

②2014-12-6CN Distribution of Seaweed

P1: Vegetation of the sea is more primitive on the evolutionary scale than that of the land. Different varieties of seaweed vary tremendously in form and elaborateness of organization, ranging from single-celled, microscopic flagellates to giant kelp which grow to be five or six hundred feet long. They have no flowers or seeds, their reproduction and distribution being accomplished by asexual spores which are simpler structures than seeds. They do not have roots but are anchored to the substratum  by  a  structure  called  a  “holdfast"  and  absorb  necessary  mineral  nutrients  directly  from the sea water through their leaf-like fronds. Like land plants, they possess chlorophyll and carry out photosynthesis, through which they utilize the energy of sunlight to synthesize carbohydrates, proteins, and fats from water, carbon dioxide, and, as required, other inorganic chemicals. These products differ chemically from their analogues in land plants, however.

•    P2: Seaweeds are found throughout the world's oceans and seas, inhabiting about 2 percent of the seafloor. Most species of seaweed live directly on the seafloor where they grow on rock, sand, mud, and coral. Other species live on other organisms and as part of artificial surfaces like fouling communities (plants and animals that live on pilings, boat bottoms, and the like). Some seaweeds are very selective about the surfaces they attach to, whereas other seaweeds do not have this degree of specialization. The presence of benthic (living on the seafloor) seaweeds defines the inner continental shelf, where the marine community largely depends on the food and protection that seaweeds provide. Life on the outer continental shelf and in the deep sea is quite different in the absence of seaweeds. The distinction between the inner and outer shelves is based on the compensation depth of algae. The compensation depth is the depth of water at which there is just enough light for algae to survive. At that depth all the oxygen produced by photosynthesis is consumed by the algae's respiration, so that no further growth can occur.

•    P3: Seaweed boundaries are not necessarily stable. The areas of the world most favorable to seaweed diversity include both sides of the North Pacific Ocean, Australia, southwestern Africa, and the Mediterranean Sea. Several physical and biological factors have been mentioned as potentially restrictive to seaweed distribution. Among these, temperature, sometimes in combination with some specific day length requirements for reproduction, is probably the most important. Some other factors critical in governing the distribution of seaweeds are duration of tidal exposure and desiccation, wave action and surge, salinity, and availability of mineral nutrients.

P4: Adaptation as applied to marine algae provides one of the simplest and most attractive examples of the physiological adaptation of plants to the environmental conditions in which they live. It is almost certainly for this reason that the theory was proposed that the vertical distribution of red, brown, and green algae could be explained by their accessory photosynthetic pigments, the presence of which gives the seaweeds their characteristic colors, a concept known as chromatic adaptation. The most frequently cited evidence involving marine algae is a study by Levring (1947), in which the photosynthesis of green algae was shown to decrease with depth in coastal waters more rapidly than the underwater irradiance. The concept of chromatic adaptation was proposed in 1883 and was accepted for about 100 years, until it was realized that such zonation did not necessarily occur and that the distribution of seaweeds depended more on herbivory (the consumption of plant material), competition, varying concentration of the specialized pigments, and the ability of seaweeds to alter their forms of growth. Indeed, some recent evidence would seem to support the hypothesis of chromatic adaptation because the depth record (295 meters, or 973 feet) for seaweeds is held by a yet undescribed species of red algae from the Bahamas, However, the green alga Rhipiliopsis profunda is close behind this record at 268 meters (884 feet).

•    P5: Temperature determines the performance of seaweeds, and indeed all organisms, at the fundamental levels of enzymatic processes and metabolic function. The greatest diversity of algal species is in tropical waters. Theoretically, increased warmth should fuel the growth of seaweed—as evidenced by seasonal dead zones that form at the mouths of many rivers worldwide when the plants bloom, die and, while decaying, suck up all the available oxygen in the seawater. But temperature is not usually a limiting factor for algae that live in tropical and subtropical seas. Although temperatures in intertidal areas (those areas between high and low tides) may become too warm and contribute to seasonal mass mortality of many seaweeds and the animals they shelter. Some researchers found that increasing temperatures, although initially enhancing the growth of phytoplankton, also allowed increased grazing by zooplankton (microscopic animals) and bacteria. "As temperature raises, the zooplankton start to grow faster than the phytoplankton," O'Connor explains. "The zooplankton are more abundant and faster-growing, and are able to eat all the phytoplankton in warmer water. This creates a bottleneck in the food chain that could have large implications for the ocean's food web."

题目

•    P1: Vegetation of the sea is more primitive on the evolutionary scale than that of the land. Different varieties of seaweed vary tremendously in form and elaborateness of organization, ranging from single-celled, microscopic flagellates to giant kelp which grow to be five or six hundred feet long. They have no flowers or seeds, their reproduction and distribution being accomplished by asexual spores which are simpler structures than seeds. They do not have roots but are anchored to the substratum  by  a  structure  called  a  “holdfast"  and  absorb  necessary  mineral  nutrients  directly  from the sea water through their leaf-like fronds. Like land plants, they possess chlorophyll and carry out photosynthesis, through which they utilize the energy of sunlight to synthesize carbohydrates, proteins, and fats from water, carbon dioxide, and, as required, other inorganic chemicals. These products differ chemically from their analogues in land plants, however.

1.   The word “artificial” in the paragraph 2 is closest in meaning to

A.   suitable

B.   human-made

C.   uneven

D.   available

2.   What can be inferred from paragraph 2 about the outer continental shelf?

A.   The outer continental shelf contains more benthic seaweeds than the deep sea does.

B.   The outer continental shelf lacks enough sunlight to support the growth of algae.

C.   The outer continental shelf has a compensation depth that is about the same as that of the inner continental shelf.

D.   The outer continental shelf has a greater variety of marine life than does the inner continental shelf.

•    P2: Seaweeds are found throughout the world's oceans and seas, inhabiting about 2 percent of the seafloor. Most species of seaweed live directly on the seafloor where they grow on rock, sand, mud, and coral. Other species live on other organisms and as part of artificial surfaces like fouling communities (plants and animals that live on pilings, boat bottoms, and the like). Some seaweeds are very selective about the surfaces they attach to, whereas other seaweeds do not have this degree of specialization. The presence of benthic (living on the seafloor) seaweeds defines the inner continental shelf, where the marine community largely depends on the food and protection that seaweeds provide. Life on the outer continental shelf and in the deep sea is quite different in the absence of seaweeds. The distinction between the inner and outer shelves is based on the compensation depth of algae. The compensation depth is the depth of water at which there is just enough light for algae to survive. At that depth all the oxygen produced by photosynthesis is consumed by the algae's respiration, so that no further growth can occur.

3.   According to paragraph 2, all of the following are true of seaweeds EXCEPT:

A.   Seaweeds provide food and protection for other organisms.

B.   Seaweeds can grow on both living and nonliving things.

C.   Some seaweeds select specific surfaces to attach to, while others are not selective.

D.   Two percent of seaweed species live on the ocean floor.

•    P3: Seaweed boundaries are not necessarily stable. The areas of the world most favorable to seaweed diversity include both sides of the North Pacific Ocean, Australia, southwestern Africa, and the Mediterranean Sea. Several physical and biological factors have been mentioned as potentially restrictive to seaweed distribution. Among these, temperature, sometimes in combination with some specific day length requirements for reproduction, is probably the most important. Some other factors critical in governing the distribution of seaweeds is duration of tidal exposure and desiccation, wave action and surge, salinity, and availability of mineral nutrients.

4.   The word  “duration”in the passage is closest in meaning to

A.   frequency

B.   force of impact

C.   length of time

D.   occurrence

P4: Adaptation as applied to marine algae provides one of the simplest and most attractive examples of the physiological adaptation of plants to the environmental conditions in which they live. It is almost certainly for this reason that the theory was proposed that the vertical distribution of red, brown, and green algae could be explained by their accessory photosynthetic pigments, the presence of which gives the seaweeds their characteristic colors, a concept known as chromatic adaptation. The most frequently cited evidence involving marine algae is a study by Levring (1947), in which the photosynthesis of green algae was shown to decrease with depth in coastal waters more rapidly than the underwater irradiance. The concept of chromatic adaptation was proposed in 1883 and was accepted for about 100 years, until it was realized that such zonation did not necessarily occur and that the distribution of seaweeds depended more on herbivory (the consumption of plant material), competition, varying concentration of the specialized pigments, and the ability of seaweeds to alter their forms of growth. Indeed, some recent evidence would seem to support the hypothesis of chromatic adaptation because the depth record (295 meters, or 973 feet) for seaweeds is held by a yet undescribed species of red algae from the Bahamas, However, the green alga Rhipiliopsis profunda is close behind this record at 268 meters (884 feet).

5. Why does the author mention “a yet undescribed species of red algae from the Bahamas"?

A.   To suggest that the concept of chromatic adaptation applies only to algae living in deep waters.

B.   To argue that location is more important than chromatic adaptation in determining the vertical distribution of algae.

C.   To emphasize the difficulty of testing the concept of chromatic adaptation in deep waters.

D.   To provide information that may confirm the idea that chromatic adaptation is responsible for the vertical distribution of algae.

6.   What  can  be  inferred  from  the  author’s  discussion  of  the  green  algae  Rhipiliopsis  profunda  in paragraph 4?

A.   Chromatic adaptation may not be an adequate explanation for the vertical distribution of algae.

B.   All types of algae share the same accessory photosynthetic pigments.

C.   Chromatic adaptation is responsible for the distribution of red algae but not for the distribution of green algae.

D.   Both red and green algae absorb red wavelengths.

7.   Which of the sentences below best expresses the essential information in the highlighted sentence in the Paragraph? Incorrect choices change the meaning in important ways or leave out essential information.

A.   For about 100 years, chromatic adaptation was thought to have a greater impact on seaweed distribution than various other factors such as herb ivory and competition.

B.   The hypothesis of chromatic adaptation was accepted for about 100 years until it was concluded that other factors could explain the distribution of seaweeds.

C.   About 100 years after the concept of chromatic adaptation was developed, it was realized that seaweed zonation occurred even in the absence of chromatic adaptation.

D.   Until the hypothesis of chromatic adaptation became widely accepted 100 years after it was proposed, various other factors were thought to determine the distribution of seaweeds.

•    P5: Temperature determines the performance of seaweeds, and indeed all organisms, at the fundamental levels of enzymatic processes and metabolic function. The greatest diversity of algal species is in tropical waters. Theoretically, increased warmth should fuel the growth of seaweed—as evidenced by seasonal dead zones that form at the mouths of many rivers worldwide when the plants bloom, die and, while decaying, suck up all the available oxygen in the seawater. But temperature is not usually a limiting factor for algae that live in tropical and subtropical seas, although temperatures in intertidal areas (those areas between high and low tides) may become too warm and contribute to seasonal mass mortality of many seaweeds and the animals they shelter. Some researchers found that increasing temperatures, although initially enhancing the growth of phytoplankton, also allowed increased grazing by zooplankton (microscopic animals) and bacteria. "As temperature raises, the zooplankton start to grow faster than the phytoplankton," O'Connor explains. "The zooplankton are more abundant and faster-growing, and are able to eat all the phytoplankton in warmer water. This creates a bottleneck in the food chain that could have large implications for the ocean's food web."

8.   What is the author’s purpose in discussing “temperatures in intertidal areas ?

To emphasize the idea that warm temperatures can be just as dangerous to algae as cold temperatures To identify a limiting factor for algae common to both tropical seas and waters at higher latitudes

To compare the causes of seaweed mortality in tropical seas and in seas at higher latitudes

To note an exception to the idea that temperature does not limit the growth of algae in tropical and subtropical waters

9.   The word “mortality” in the passage is closest in meaning to

A.   movement

B.   exposure

C.   death

D.   injury

10. According to paragraph 5，all of the following are true when temperatures increase EXCEPT:

A.   The number of phytoplankton is likely to grow.

B.   Zooplankton feed on phytoplankton.

C.   The disappearance of Phytoplankton is not possible.

D.   Zooplankton will outnumber phytoplankton.

•    P2: Seaweeds are found throughout the world's oceans and seas, inhabiting about 2 percent of the seafloor. Most species of seaweed live directly on the seafloor where they grow on rock, sand, mud, and coral. Other species live on other organisms and as part of artificial surfaces like fouling communities (plants and animals that live on pilings, boat bottoms, and the like).

Some seaweeds are very selective about the surfaces they attach to, whereas other seaweeds do not have this degree of specialization. [■] The presence of benthic (living on the seafloor) seaweeds defines the inner continental shelf, where the marine community largely depends on the food and protection that seaweeds provide. [■] Life on the outer continental shelf and in the deep sea is quite different in the absence of seaweeds. The distinction between the inner and outer shelves is based on

the compensation depth of algae. [■] The compensation depth is the depth of water at which there is just enough light for algae to survive. At that depth all the oxygen produced by photosynthesis is consumed by the algae's respiration, so that no further growth can occur. [■]

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

The distinction between the inner and outer shelves is based on the compensation depth of algae. Where would the sentence best fit?

Click on a square [■] to add the sentence to ' the passage.

12. 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 answer choices 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. Drag your choices to the spaces where they belong. To review the passage, click on View Text.

Seaweeds are multicellular algae living in the oceans.•

Answer Choices

A Seaweeds are limited to areas with enough light for them to survive, with most living on the seafloor and more species inhabiting warm waters than colder waters.

B Some recent evidence shows that the color of any species of seaweed is determined by the amount of chlorophyll a contained in its accessory pigments.

C The greatest diversity of seaweed is found in warm waters, and seaweed cannot survive when the temperature is either too hot or too cold.

D Seaweeds are distributed most evenly over both sides of the North Pacific Ocean, Australia, southwestern Africa, and the Mediterranean Sea.

E The chromatic-adaptation hypothesis was long thought to explain the vertical distribution of seaweed, but current belief is that distribution is better explained by other factors.

F The growth of phytoplankton accelerates the bloom of zooplankton surviving on slaughtering the marine algae, which in turn creates a bottleneck in the food chain.

参考答案： 1-5：BBDCD

6-10：ABDCC

11：C

12：ACE

解析

1.【词汇题】artificial 意为"人造的”。

2.【推断题】从文中得知 outer shelf 没有海潭 shelf 是有海藻的，且海藻能够存活是因为有足够的，所以反推outer shelf没有海藻是因为没有足够光线。3.【否定事实信息题】这种题型最好用的方法是带着选项去原文对应一一排除。A, B, C 都明显都对应，选项 D 说 2%的海藻长在海底，而原文是指海藻占据了 2%的海底。

4.【词汇题】duration 意为"持续时间”。

5.【修辞目的题】因为巴哈马一种未命名的红藻证明了海藻的存活深度，所以能支持色适应理论。因此答案为 D。

6.【推断题】前文提及巴哈马一种未命名的红藻是为了提供证据支持色适应理论能够解释海藻的垂直分布现象，紧接着转折提到 Rhipiliopsis profunda 这种绿藻的深度与巴哈马红藻不一致，所以推翻之前的色适应理论。                                                                                                            7.【句子简化题】B 选项与原文句子结构基本相同，仅作了文字上的概括。

8.【修辞目的题】文中提到尽管潮间带区域的温度可能过高并且导致大量海藻以及那些以海藻为栖息地的动物的死亡，但是温度对于热带和亚热带的藻类来说并非是限制因素。所以作者提及潮间带区域的温度是为了说明这种个例并不能证实温度会限制热带及亚热带地区藻类的生长。

9. 【词汇题】mortality 意为“死亡率”。

10.【否定事实信息题】文中提到浮游动物会吃掉所有的浮游植物，所以浮游植物消失是有可能的。

11. 【句子插入题】distinction 对应空前 different compensation depth 空后有重现。

12.【文章总结题】本文介绍了海藻的分布情况。海藻生 存的必要条件是光线，大多数海藻长在海底；重点介绍了一种色适应理论，这个理论原本被长期接受，后被推翻；温度上升时海藻数量也会增加，但温度过高时海藻又存活。因此涉及影响海藻分布因素的 A、C、B、D、

F 三个选项都属于细节，偏离主旨。

听力机经

听力文本

Narrator: Listen to a conversation between a student and her biology professor.

Professor: Hi, Suzanne. Y o u ' v e been keeping busy?

Suzanne: Really busy. It' s that time of the semester. I'm glad I turned in the first draft as my paper for your class already. Thanks for getting to it so quickly and for seeing me today.

Professor: Sure. Yes, it looks like it will be a good paper. Great topic but I think it could use a little more work because it' s just that I found it a bit unclear in places so I want to make sure I understand what you intended to do before I make suggestions for admissions.

Suzanne: Okay.

Professor: So can you summarize, tell me in a few sentences the main ideas you want to get across?

Suzanne: Okay. Well, honeybees can communicate the location of food to other honeybees and the idea was to describe how they use Earth' s magnetic field in that process.

Professor: To help them communicate?

Suzanne: No, to help them find their way, to navigate.

Professor: Okay. See, I w a s n ' t sure you separated those two ideas. One that honeybees could communicate with other honeybees and two, that they might be using the magnetic field but only for navigation.

Suzanne: Oh.

Professor: Are you sure you understand that?

Suzanne: I think so. After they find food and return to the hive, they move in different ways to communicate different things. Like they do a simple dance, the round dance, to communicate that a food source is nearby. But they do a more complex dance, the waggle dance, if the food is farther than, like  seventy-five meters away. Both dances convey information about the distance from the hive to the food source and the waggle dance conveys the direction of the food from the hive.

Professor: Okay, good. And where is the magnetic field for that?

Suzanne: Well, they have cells in their body that contains iron. So we assume that

t h e y ' r e able to sense Earth' s magnetic field, which might help them navigate. It' s likely that they have an internal compass, like if they get blown off course by the wind, they can get back on course.

Professor: Okay, good. The thing is in your draft, it rather showed that the magnetic field was irrelevant to the bee dance  through communication. I  looked  over your list of sources and I thought I could see why.

Student: There' s a problem with my sources?

Professor: Well, the article you sited on magnetic navigation i s n ' t very academic. It' s more of a general interest article. I thought that maybe you relied too much on its wording so I was going to suggest you go back and find the original research report which presents the information in a more precise and clear way. But maybe you just need to revise your own wording in your paper. I think when you look at it again you will know what I'm talking about. If you have any questions, come by again.

题目

1.   Why does the woman go to see the professor?

A.   To ask the professor to explain a point she was confused about in class

B.   To discuss an early version of a paper she is writing for class

C.   To explain what revisions she made to a paper in response to the professor's comments

D.   To hand in a paper on honeybees that she just completed

2.   What mistaken idea does the professor suspect the woman might have?

A.   That honeybees dance only for the purpose of communicating with one another

B.   That scientists are certain that bees use magnetic fields for navigation

C.   That Earth's magnetic field helps honeybees communicate with one another

D.   That honeybees have a highly social organization

3.   According to the woman, what factor determines whether a honeybee does a round dance or the more complex waggle dance?

A.   The type of food it found

B.   The richness of a food source it found

C.   The relative distance of a food source from the hive

D.   The number of bees observing the dance

4.   During the conversation, what does the professor come to realize about the woman?

A.   That she understands what Earth's magnetic field helps honeybees do

B.   That she does not understand some aspects of honeybee communication

C.   Why she chose a nonacademic source of information for her paper

D.   That she accurately expressed in the paper exactly what she had intended to express

5.   What does the professor imply when he suggests the woman should find the original research report?

A.   He is not familiar with the article the woman used for her paper.

B.   He wants the woman to compare the original research report with a more recent one.

C.   The original research report includes additional experiments that the woman should mention.

D.   The source used by the woman presents information in an unclear manner.

答案

1. B 2. B 3. C 4. B 5. D

文章大意

女生去见教授，两个人开始谈论女生几天前交上的一篇论文的初稿。教授先让女生说了说她想表达的主要意思，女生说她主要想说明蜜蜂可以利用磁场来告知其他蜜蜂食物的位置。但是教授随后指出，女生在论文里写的“蜜蜂可以和同伴交流以告知其食物位置”和“蜜蜂利用磁场导航”之间并没有清晰明确的联系，并要求女生回去再查一下更加可靠的学术文献。

口语机经

1、考题出现时间：2016-7-3CN 阅读：Dormancy

In the really harsh natural environment, some animals will use dormancy to protect themselves from the nature. In a word, they will avoid exposure to certain elements in the environment and use slow metabolism to preserve energy.

听 力 ：Professor used an example of the lungfish to demonstrate the term, lungfish lives in the shallow lakes that faces the possible consequences of drying up. If the lake dries up, then the lungfish is cooked, so they will explore certain method to prevent that from happening. So basically what the lungfish do is to dig a hole through the mud at the bottom of the lake, its body will be curled up and buried in the mud, so the covered mud could be a proactive coat for the lungfish that keeps them away from the heat and also keep the moisture inside the body. The lungfish will keep the body still and breathe really slow, the heart beat is slowing down as well. Usually the lungfish relies on eating crabs and small fish to survive but since it lives in the shelter, it doesn’t need to eat anything at all. They can survive in this shelter for months, or even years until the lake returns.

2、考题出现时间：2015-5-30CN

阅读：Appeasement 开头的一种动物的 behavior。为了 avoid stronger animal 会做出

—些行为或者放出一些信号以示弱，

听力：教授举了 wolf 为例子，当狼群为了食物争夺的时候，小的狼会低下自己的头以避免伤害。这时候大的狼会不去伤者它们。

3、考题出现时间：2015-9-13CN

Recruitment

Reading: Release signals to inform other insects to cool and cooperate.

Listening: There is a type of ant called the fire ant living in South America that live in nests. Some ants have a special job: They have to leave the nests to find food. When one ant finds a piece of fruit that is too big or it to carry back, it will walk back while at the same time releasing a chemical, which will form a chemical trail on the way. When it arrives, other ants could follow the trail and find the fruit and then carry it back together.

写作机经

　1、考题出现时间：2017-3-11CN

　　阅读：保护濒危鸟类Hermit Ibis很困难

　　1) habitat destruction生存环境的破坏，大多由于人的占用导致。

　　2)附近捕食者(比如秃鹰和乌鸦)对幼鸟和蛋的攻击。Eggs and juvenile are vulnerable to the predators, which, however, cannot be killed because they are also important to ecosystem。

　　3)保护濒危物种通常科学家会raise them in captivity 然后release into the wild, 但是Hermit Ibis是迁徙类动物，它们是从父母那里学习how and where to migrate，如果人工饲养然后放回大自然，它们无法生存。

　　听力：问题可以解决

　　1) hermit ibis可以在很多地方筑巢，人工搭建的栖息地，比如建筑物的外墙。这个不是问题。

　　2)虽然eggs and juvenile are vulnerable，但是它们的天敌都比较胆小，只要在eggs and juvenile成年之前人类通过吹哨子赶走天敌，Hermit Ibis成年后生活就没有问题了。

　　3)人类也可以教给年幼的hermit ibis如何迁徙，比如pilot带着年幼的hermit ibis随着它们迁徙的路线飞行，它们也可以学会如何迁徙，放回大自然后它们的生存就不会有任何问题。

　　2、考题出现时间：2016-12-3CN

　　阅读：吸血鱿鱼是否以海雪为生

　　1)深海区的最小氧气含量。

　　2)容易被捕食者发现。

　　3)头足类动物的行为。

　　听力：和阅读相反

　　1)吸血鱿鱼这一特殊物种，需要的含氧量并不多。

　　2)本身会发光，并且自然光线阻挡了捕食者靠近。

　　3)这一行为是鱿鱼优势，更能准确定位到食物。

　　3、考题出现时间：2016-7-10CN

　　第一部分：Three possible theories of what a sea-dwelling microorganism’s eye might be for.

　　阅读观点：

　　1)The eye is used for following preys.

　　2)The eye is used for sensing sunlight.

　　3)The eye is used for aiming at having better accuracy at other tiny life forms when it is going to stab them.

　　听力观点：

　　1)Other closely related microorganisms, which have no eyes, could follow their prey successfully. Therefore, their eyes must be for other purposes.

　　2)Scientists studying the evolution of microorganism find that they are becoming less and less dependent on sunlight for energy. Compared with their ancestor, the sea-dwelling microorganism is with a much more complex

　　3)After examining the eye thoroughly, researchers find that its eye couldn’t focus quite well, thus not being able to have better accuracy at other tiny life forms when stabbing them.

　　4、考题出现时间：2015-12-19CN

　　阅读：绘画中动物的意义

　　1)绘画中动物被人捕获，身上被箭和矛刺伤。

　　2)打猎时人们用动物的头来武装自己。

　　3)动物身上有一种魔力，画动物是为了能够捕获到更多的猎物。

　　听力反驳：

　　1)只有一小部分动物被捕，而且只有一小部分动物被箭和矛刺伤。

　　2)只有少数人用动物的头来武装自己。

　　3)动物还有其他的作用，比如用来祭祀等。

　　5、考题出现时间：2015-12-12CN

　　阅读：动物园里犀牛遇到生育问题的原因

　　1)犀牛被喂食大量的干草和苜蓿，导致激素增加，影响生育。

　　2)总是在坚硬的地面上行走，出现了足部疾病。

　　3)一些犀牛出现脑失调的现象。

　　听力反驳：

　　1)可以改变犀牛的饮食结构，减少干草和苜蓿的食用量。

　　2)有先进的设备能及早检测到这种足部疾病，防止疾病扩散。

　　3)犀牛出现脑失调是因为母牛的年龄太大，身体中会分泌有害化学物质，只要控制产龄就可以解决这一问题。

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