The daytime quality of light in forests varies with the density of the vegetation, the angle of the Sun, and the amount of cloud in the sky. Both animals and plants have different appearances in these various lighting conditions. A color or pattern that is relatively indistinct in one kind of light may be quite conspicuous in another.
In the varied and constantly changing light environment of the forest, an animal must be able to send visual signals to members of its own species and at the same time avoid being detected by predators. An animal can hide from predators by choosing the light environment in which its pattern is least visible. This may require moving to different parts of the forest at different times of the day or under different weather conditions, or it may be achieved by changing color according to the changing light conditions. Many species of amphibians (frogs and toads) and reptiles (lizards and snakes) are able to change their color patterns to camouflage themselves. Some also signal by changing color. The chameleon lizard has the most striking ability to do this. Some chameleon species can change from a rather dull appearance to a full riot of carnival colors in seconds. By this means, they signal their level of aggression or readiness to mate.
Other species take into account the changing conditions of light by performing their visual displays only when the light is favorable. A male bird of paradise may put himself in the limelight by displaying his spectacular plumage in the best stage setting to attract a female. Certain butterflies move into spots of sunlight that have penetrated to the forest floor and display by opening and closing their beautifully patterned wings in the bright spotlights. They also compete with each other for the best spot of sunlight.
Very little light filters through the canopy of leaves and branches in a rain forest to reach ground level—or close to the ground—and at those levels the yellow-to-green wavelengths predominate. A signal might be most easily seen if it is maximally bright. In the green-to-yellow lighting conditions of the lowest levels of the forest, yellow and green would be the brightest colors, but when an animal is signaling, these colors would not be very visible if the animal was sitting in an area with a yellowish or greenish background. The best signal depends not only on its brightness but also on how well it contrasts with the background against which it must be seen. In this part of the rain forest, therefore, red and orange are the best colors for signaling, and they are the colors used in signals by the ground-walking Australian brush turkey. This species, which lives in the rain forests and scrublands of the east coast of Australia, has a brown-to-black plumage with bare, bright-red skin on the head and neck and a neck collar of orange-yellow loosely hanging skin. During courtship and aggressive displays, the turkey enlarges its colored neck collar by inflating sacs in the neck region and then flings about a pendulous part of the colored signaling apparatus as it utters calls designed to attract or repel. This impressive display is clearly visible in the light spectrum illuminating the forest floor.
Less colorful birds and animals that inhabit the rain forest tend to rely on other forms of signaling other than the visual, particularly over long distances. The piercing cries of the rhinoceros hornbill characterize the Southeast Asian rain forest, as do the unmistakable calls of the gibbons. In densely wooded environments, sound is the best means of communication over distance because in comparison with light, it travels with little impediment from trees and other vegetation. In forests, visual signals can be seen only at short distances, where they are not obstructed by trees. The male riflebird exploits both of these modes of signaling simultaneously in his courtship display. The sounds made as each wing is opened carry extremely well over distance and advertise his presence widely. The ritualized visual display communicates in close quarters when a female has approached.
Paragraph 1: The daytime quality of light in forests varies with the density of the vegetation, the angle of the Sun, and the amount of cloud in the sky. Both animals and plants have different appearances in these various lighting conditions. A color or pattern that is relatively indistinct in one kind of light may be quite conspicuous in another.
1. The phrase conspicuous in the passage is closest in meaning to
○Commom
○Noticeable
○Different
○Colorful
Paragraph 2: In the varied and constantly changing light environment of the forest, an animal must be able to send visual signals to members of its own species and at the same time avoid being detected by predators. An animal can hide from predators by choosing the light environment in which its pattern is least visible. This may require moving to different parts of the forest at different times of the day or under different weather conditions, or it may be achieved by changing color according to the changing light conditions. Many species of amphibians (frogs and toads) and reptiles (lizards and snakes) are able to change their color patterns to camouflage themselves. Some also signal by changing color. The chameleon lizard has the most striking ability to do this. Some chameleon species can change from a rather dull appearance to a full riot of carnival colors in seconds. By this means, they signal their level of aggression or readiness to mate.
2. According to paragraph 2, what is problematic about an animal's sending visual signals to members of its own species?
○Signs that make an animal visible to its species also make it visible to predators.
○An animal that changes color to avoid predators can confuse members of its species.
○Changing light may require an animal to move beyond the visual range of other members.
○The animal may mistakenly signal aggression when it meant to signal readiness to mate.
3. The word signal in the passage is closest in meaning to
○change
○imitate
○communicate
○hide
4. According to paragraph 2, all of the following are reasons amphibians and reptiles change color EXCEPT
○changing seasons
○to signal others of their species
○to match the light
○to hide from predators
Paragraph 3: Other species take into account the changing conditions of light by performing their visual displays only when the light is favorable. A male bird of paradise may put himself in the limelight by displaying his spectacular plumage in the best stage setting to attract a female. Certain butterflies move into spots of sunlight that have penetrated to the forest floor and display by opening and closing their beautifully patterned wings in the bright spotlights They also compete with each other for the best spot of sunlight.
5. According to paragraph 3, butterflies move into spots of sunlight in order to
○warm their wings in order to open them
○compete with each other
○take advantage of favorable light conditions on the forest floor
○imitate birds of paradise
Paragraph 4: Very little light filters through the canopy of leaves and branches in a rain forest to reach ground level—or close to the ground—and at those levels the yellow-to-green wavelengths predominate. A signal might be most easily seen if it is maximally bright. In the green-to yellow lighting conditions of the lowest levels of the forest, yellow and green would be the brightest colors, but when an animal is signaling, these colors would not be very visible if the animal was sitting in an area with a yellowish or greenish background. The best signal depends not only on its brightness but also on how well it contrasts with the background against which it must be seen. In this part of the rain forest, therefore, red and orange are the best colors for signaling, and they are the colors used in signals by the ground-walking Australian brush turkey. This species, which lives in the rain forests and scrublands of the east coast of Australia, has a brown to-black plumage with bare, bright-red skin on the head and neck and a neck collar of orange-yellow loosely hanging skin. During courtship and aggressive displays, the turkey enlarges its colored neck collar by inflating sacs in the neck region and then flings about a pendulous part of the colored signaling apparatus as it utters calls designed to attract or repel. This impressive display is clearly visible in the light spectrum illuminating the forest floor.
6. According to paragraph 4, what is true about light that reaches ground level?
○It reveals only the yellow and green colors animals use to signal each other.
○It reflects the yellow and green colors to make the floor as bright as sunshine.
○It camouflages animals whose natural colors are yellow and green.
○It consists mostly of yellow-to-green wavelengths.
7. Which 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.
○When an animal is signaling in an area with green-to yellow lighting condition. It’s signal will not be visible if the background is brightly lit.
○In the lowest levels of the forest, an animal's signals are not easily seen unless there is a yellowish or greenish background.
○In the green-to-yellow lighting conditions at the lowest levels of the forest, only signals that are themselves green or yellow will be bright enough to be seen in most areas.
○Although green and yellow would be the brightest colors near the forest floor, these colors would make poor signals whenever the forest background was also in the green-to-yellow range.
8. The word inflating in the passage is closest in meaning to
○Coloring
○Enlarging
○Loosening
○Heating
9. Which of the following can be inferred from paragraph 4 about yellow and green colors compared with red and orange colors at the bottom of the forest?
○Yellow and green are better colors for signaling than red and orange colors.
○Orange and red are brighter colors than yellow and green.
○Yellow and green are likely to be more common in the background than red and orange.
○Orange and red colors do not contrast as well with the forest floor as yellow and green do.
Paragraph 5: Less colorful birds and animals that inhabit the rain forest tend to rely on forms of signaling other than the visual, particularly over long distances. The piercing cries of the rhinoceros hornbill characterize the Southeast Asian rain forest, as do the unmistakable calls of the gibbons. In densely wooded environments, sound is the best means of communication over distance because in comparison with light, it travels with little impediment from trees and other vegetation. In forests, visual signals can be seen only at short distances, where they are not obstructed by trees. The male riflebird exploits both of these modes of signaling simultaneously in his courtship display. The sounds made as each wing is opened carry extremely well over distance and advertise his presence widely. The ritualized visual display communicates in close quarters when a female has approached.
10. What can be inferred from paragraph 5 about the less colorful birds and animals that inhabit the forest?
○These species are less able to see color. and therefore they communicate with one another using nonvisual signals.
○These species generally live in less densely wooded environments than more colorful birds and animals do.
○The cries of these species do not carry as well over distances as the cries of more colorful birds and animals.
○These species depend more on nonvisual signals for communication because they are less visible in their environment.
11. The word impediment in the passage is closest in meaning to
○obstruction
○effort
○delay
○resistance
12. The word exploits in the passage is closest in meaning to
○repeats
○makes use of
○increases the intensity of
○recognizes
Less colorful birds and animals that inhabit the rain forest tend to rely on forms of signaling other than the visual, particularly over long distances. ■ The piercing cries of the rhinoceros hornbill characterize the Southeast Asian rain forest, as do the unmistakable calls of the gibbons. ■ In densely wooded environments, sound is the best means of communication over distance because in comparison with light, it travels with little impediment from trees and other vegetation. ■ In forests, visual signals can be seen only at short distances, where they are not obstructed by trees. ■ The male riflebird exploits both of these modes of signaling simultaneously in his courtship display. The sounds made as each wing is opened carry extremely well over distance and advertise his presence widely. The ritualized visual display communicates in close quarters when a female has approached.
13. Look at the four squares [■] that indicate where the following sentence could be added to the passage.
There is also the long, rather terrifying call of the male orangutan, which carries over considerable distances to advertise his presence.
Where would the sentence best fit?
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.
In the rain forest, an animal must be able to send signals to members of its own species and at the same time avoid being detected by predators.
●
●
●
Answer Choices
○Animals that have different predators at different times of day change color to avoid being detected.
○To escape notice, an animal may move or change color so that its color pattern is not visible.
○To be noticed, an animal may draw attention to the contrast F between its colors and the colors of its environment.
○Yellow and green are the most common colors found in the r rain forest.
○Animals must have signals for aggression as well as to indicate readiness to mate.
○An animal may use sound rather than color to attract attention, because sound signals are not hindered by light conditions.
查看正確答案和解析
版權聲明：本原創(chuàng)文章版權歸“新通外語網(wǎng)（）”所有，未經書面許可不得轉貼、轉載。否則，新通教育網(wǎng)將追究其相關法律責任。
參考答案：
1. 2
2. 1
3. 3
4. 1
5. 3
6. 4
7. 4
8. 2
9. 3
10. 4
11. 1
12. 2
13. 2
14. To escape…
To be noticed…
An animal may…
森林中白天的光照質量隨著植被密度、太陽角度以及天空中云的數(shù)量的變化而變化。在不同的光照條件下，動植物會有不同的表現(xiàn)。在某種光照下相對較難辨認的顏色或式樣，在另外一種光照下也許會變得相當顯眼。
在多樣和不斷變化的森林光照環(huán)境下，動物必須能夠發(fā)送視覺信號給自己的同類，同時避免被捕食者發(fā)現(xiàn)。動物可以選擇最不易看得見的光照環(huán)境來躲避捕食者的視線。這就要求動物能在白天不同的時間或者在不同的天氣條件下移動到森林的不同方位，或者，它們也可以根據(jù)不同的光照來改變自身的顏色。很多兩棲動物（青蛙和蟾蜍）和爬行動物（蜥蜴和蛇）都可以通過改變顏色圖案來偽裝自己。有些動物還通過改變顏色來發(fā)出信號。變色龍在這方面有著最驚人的能力。有些變色龍物種可以在幾秒鐘之內就把暗淡的外表變得燦爛奪目。通過這種方式，它們可以傳達出攻擊程度和交配意愿。
其他的物種則只有在光照對它們有利的時候才會利用光照，來進行視覺上的自我展現(xiàn)。雄性極樂鳥會置身于匯聚的光線之下，在最佳的場景中展現(xiàn)自己繽紛絢爛的羽翼，以吸引雌鳥的注意。某些蝴蝶則飛到穿透森林的太陽光點處，，在明亮的光點中扇動著帶有美麗圖案的翅膀來展現(xiàn)自己。它們還會互相爭奪最佳的光照位置。
很少有光能夠穿透熱帶雨林的樹冠層到達地平面——或是接近地面——而能達到底部的主要是黃綠光波。如果是色彩極為明亮的信號，可能更容易被看見。在森林底層的黃綠光照條件下，黃色和綠色是最明亮的顏色，但是當動物發(fā)送信號時，如果處于淺黃或淺綠的背景下，這些顏色就不容易看到了。最佳的信號不僅取決于其明亮度，還在于它與背景顏色的對比度。因此，在熱帶雨林這塊區(qū)域，紅色和橙色是最佳的信號顏色，而這也是地面行走的澳大利亞灌叢火雞最善于使用的信號顏色。這個物種生活在澳大利亞東海岸的雨林和灌木叢中，長著黑棕色的羽毛，有著光禿禿、亮紅色的頭和脖子，頸圈上是一層橙黃色的松垮垮的皮。在求愛期和發(fā)起進攻時，火雞通過給頸部液囊充氣擴張頸圈，晃動著下垂的鮮艷的信號裝置，隨之發(fā)出叫聲來吸引異性或擊退敵人。在照亮雨林底層的光譜環(huán)境下，能夠清晰地看到這種讓人印象深刻的展示。
對于生活在熱帶雨林中的色彩不那么鮮艷的鳥類和動物來說，它們則傾向于發(fā)出其他形式的信號而非視覺信號，尤其是在跨越長距離時。比如說，東南亞雨林中極有代表性的能發(fā)出尖銳叫聲的犀鳥和叫聲清厲的長臂猿。在樹木繁茂的環(huán)境中，聲音是最好的跨距離傳播手段。因為，相較于視覺信號，聲音幾乎不受樹木和其他植被的干擾。在森林中，只能在不被樹木阻擋的近距離地方看到視覺信號。雄性極樂鳥在求愛期則同時運用了這兩種信號傳送方式。它張開翅膀時發(fā)出的聲響能夠極好地傳送到遠距離之外，鋪天蓋地地宣傳著它的儀表風采。而當雌鳥吸引而來時，它那儀式化的視覺展現(xiàn)就得以近距離地進行交流
