TF阅读真题第875篇Life in the Desert
Life in the Desert
In the austere and inhospitable environment of the desert, each inhabitant must be highly specialized in order to survive. In spite of the common notion that a desert is deserted of life, there are actually many living organisms. The principal limiting factor for successful animal and plant species is, obviously, the dearth of water, and some of the most significant adaptations have evolved in solution to this basic problem.
In the desert, many of the plants are annuals, lasting only one season. Some are ephemerals, which arise only after the rare rains and rapidly conclude their cycle before the new drought. They have no need of any particular specialization, other than opportunism and rapid growth. The perennial plants that regularly grow year after year, in contrast, must be much more able to adjust. Normally, they have leathery leaves covered with waxy films to reduce the transpiration and evaporation of internal liquids. Many plants have reduced leaf surfaces, or they have transmuted them into sharp thorns. Some species, such as mosses and lichens, curl their leaves during the dry periods. Other plants have fleshy tissues in which they concentrate and conserve great quantities of reserve water. Still other plants grow only in the proximity of sources or basins of water dispersed in the desert (in oases)or around riverbeds where underground water flows. These plants have extremely long roots, which reach down to the moisture coming from the permanent water table. This is the case for the well-known date palm of the oases in the Sahara and the Middle East. When the water layer is too distant, however, other species live by spreading their roots along the surface in order to enjoy the moisture that condenses during the night but is insufficient to penetrate deeply into the soil.
Adaptations that are equally remarkable can be seen among the animals, which, in order to survive, have no fewer problems to resolve than do the plants. Heat and lack of water are again factors limiting the possibilities of life: the factors that must be addressed by the choices and strategies of each individual organism.
To these factors is often also added the scarcity of food, which is partially resolved by the low density of animals in the desert. Similarly to what happens during the winters of the temperate latitudes, when many species hibernate, desert animals reduce their metabolism during the summer by becoming less active, often in the shelter of rocks or underground. The same can occur in the case of prolonged drought. This seasonal behavior recalls what also happens on the scale of a single day: activities are stopped during the hottest hours, and everyone seeks shelter in the shade. Large-dimensioned species, such as hoofed or carnivorous mammals, which are endowed with relative facility of movement, as flying insects and birds are also, often undertake nomadic movements or actual migrations to find more-hospitable areas during periods that are particularly unfavorable because of high temperatures or drought.
There are many adaptations in form and function to the torrid climate of the desert. For the purpose of more easily dispersing the heat, animals in hot desert regions have smaller bodily dimensions than similar species living in colder areas. The opposite is true for the appendages, which are more developed and sometimes moist in animals living in hot areas, in order to cool off more easily. This is the case for the enormous ears of the jackrabbit- the hare of the Sonora Desert in America. Many desert animals are capable of tolerating long periods without drinking. They aid themselves in this regard by producing urine that is highly concentrated, thus reducing their loss of water. Some desert mice, alternatively, conserve the water that would be lost in respiration by making it pass through a series of intricate ducts that open into the nasal sinuses, where the air loses moisture as it cools.
1
In the desert, many of the plants are annuals, lasting only one season. Some are ephemerals, which arise only after the rare rains and rapidly conclude their cycle before the new drought. They have no need of any particular specialization, other than opportunism and rapid growth. The perennial plants that regularly grow year after year, in contrast, must be much more able to adjust. Normally, they have leathery leaves covered with waxy films to reduce the transpiration and evaporation of internal liquids. Many plants have reduced leaf surfaces, or they have transmuted them into sharp thorns. Some species, such as mosses and lichens, curl their leaves during the dry periods. Other plants have fleshy tissues in which they concentrate and conserve great quantities of reserve water. Still other plants grow only in the proximity of sources or basins of water dispersed in the desert (in oases)or around riverbeds where underground water flows. These plants have extremely long roots, which reach down to the moisture coming from the permanent water table. This is the case for the well-known date palm of the oases in the Sahara and the Middle East. When the water layer is too distant, however, other species live by spreading their roots along the surface in order to enjoy the moisture that condenses during the night but is insufficient to penetrate deeply into the soil.
Paragraph 2 suggests that the leaves of desert perennials have developed various specializations for the main purpose of
Inference Questions推理题
Acollecting rainwater
Bprotecting the rest of the plant from heat and sun
Cpreventing the loss of liquids
Ddistributing internal liquids throughout the plant
2
In the desert, many of the plants are annuals, lasting only one season. Some are ephemerals, which arise only after the rare rains and rapidly conclude their cycle before the new drought. They have no need of any particular specialization, other than opportunism and rapid growth. The perennial plants that regularly grow year after year, in contrast, must be much more able to adjust. Normally, they have leathery leaves covered with waxy films to reduce the transpiration and evaporation of internal liquids. Many plants have reduced leaf surfaces, or they have transmuted them into sharp thorns. Some species, such as mosses and lichens, curl their leaves during the dry periods. Other plants have fleshy tissues in which they concentrate and conserve great quantities of reserve water. Still other plants grow only in the proximity of sources or basins of water dispersed in the desert (in oases)or around riverbeds where underground water flows. These plants have extremely long roots, which reach down to the moisture coming from the permanent water table. This is the case for the well-known date palm of the oases in the Sahara and the Middle East. When the water layer is too distant, however, other species live by spreading their roots along the surface in order to enjoy the moisture that condenses during the night but is insufficient to penetrate deeply into the soil.
According to paragraph 2， which of the following is NOT a characteristic that can be found in some desert perennials?
Negative Factual Information Questions否定事实信息题
Aonly one season of life
Btough, waxy leaves
Cthorns in place of leaves
Dbeing located near water sources
3
In the desert, many of the plants are annuals, lasting only one season. Some are ephemerals, which arise only after the rare rains and rapidly conclude their cycle before the new drought. They have no need of any particular specialization, other than opportunism and rapid growth. The perennial plants that regularly grow year after year, in contrast, must be much more able to adjust. Normally, they have leathery leaves covered with waxy films to reduce the transpiration and evaporation of internal liquids. Many plants have reduced leaf surfaces, or they have transmuted them into sharp thorns. Some species, such as mosses and lichens, curl their leaves during the dry periods. Other plants have fleshy tissues in which they concentrate and conserve great quantities of reserve water. Still other plants grow only in the proximity of sources or basins of water dispersed in the desert (in oases)or around riverbeds where underground water flows. These plants have extremely long roots, which reach down to the moisture coming from the permanent water table. This is the case for the well-known date palm of the oases in the Sahara and the Middle East. When the water layer is too distant, however, other species live by spreading their roots along the surface in order to enjoy the moisture that condenses during the night but is insufficient to penetrate deeply into the soil.
According to paragraph 2,date palm trees are successful in the desert because they
Factual Information Questions事实信息题
Ado not need any particular specialization
Bhave long roots that find water deep underground
Care cultivated in Saharan oases for their fruits
Dspread their roots along the surface to gather moisture
4
Adaptations that are equally remarkable can be seen among the animals, which, in order to survive, have no fewer problems to resolve than do the plants. Heat and lack of water are again factors limiting the possibilities of life: the factors that must be addressed by the choices and strategies of each individual organism.
What is the main role of paragraph 3 within the passage?
Rhetorical Purpose Questions修辞目的题
ATo add the information that desert organisms continually evolve new adaptations for dealing with harsh desert conditions
BTo conclude earlier remarks by pointing out how much individual organisms vary in their adaptations to desert conditions
CTo lead to a discussion of which environmental factor, lack of water or lack of heat, has more serious consequences in the desert
DTo serve as a transition between a discussion of desert plant adaptations and desert animal adaptations
5
To these factors is often also added the scarcity of food, which is partially resolved by the low density of animals in the desert. Similarly to what happens during the winters of the temperate latitudes, when many species hibernate, desert animals reduce their metabolism during the summer by becoming less active, often in the shelter of rocks or underground. The same can occur in the case of prolonged drought. This seasonal behavior recalls what also happens on the scale of a single day: activities are stopped during the hottest hours, and everyone seeks shelter in the shade. Large-dimensioned species, such as hoofed or carnivorous mammals, which are endowed with relative facility of movement, as flying insects and birds are also, often undertake nomadic movements or actual migrations to find more-hospitable areas during periods that are particularly unfavorable because of high temperatures or drought.
The word “scarcity”in the passage is closest in meaning to
Vocabulary Questions词汇题
Aavailability
Bimportance
Cquality
Dinsufficiency
6
To these factors is often also added the scarcity of food, which is partially resolved by the low density of animals in the desert. Similarly to what happens during the winters of the temperate latitudes, when many species hibernate, desert animals reduce their metabolism during the summer by becoming less active, often in the shelter of rocks or underground. The same can occur in the case of prolonged drought. This seasonal behavior recalls what also happens on the scale of a single day: activities are stopped during the hottest hours, and everyone seeks shelter in the shade. Large-dimensioned species, such as hoofed or carnivorous mammals, which are endowed with relative facility of movement, as flying insects and birds are also, often undertake nomadic movements or actual migrations to find more-hospitable areas during periods that are particularly unfavorable because of high temperatures or drought.
The phrase”The same”in the passage refers to
Reference Questions指代题
Athe low density of animals
Bthe scarcity of food
Creduction in animals’ metabolism
Dwhat happens during winter
7
To these factors is often also added the scarcity of food, which is partially resolved by the low density of animals in the desert. Similarly to what happens during the winters of the temperate latitudes, when many species hibernate, desert animals reduce their metabolism during the summer by becoming less active, often in the shelter of rocks or underground. The same can occur in the case of prolonged drought. This seasonal behavior recalls what also happens on the scale of a single day: activities are stopped during the hottest hours, and everyone seeks shelter in the shade. Large-dimensioned species, such as hoofed or carnivorous mammals, which are endowed with relative facility of movement, as flying insects and birds are also, often undertake nomadic movements or actual migrations to find more-hospitable areas during periods that are particularly unfavorable because of high temperatures or drought.
The word “prolonged” in the passage is closest in meaning to
Vocabulary Questions词汇题
Afrequent
Bregional
Cextended
Doccasional
8
There are many adaptations in form and function to the torrid climate of the desert. For the purpose of more easily dispersing the heat, animals in hot desert regions have smaller bodily dimensions than similar species living in colder areas. The opposite is true for the appendages, which are more developed and sometimes moist in animals living in hot areas, in order to cool off more easily. This is the case for the enormous ears of the jackrabbit- the hare of the Sonora Desert in America. Many desert animals are capable of tolerating long periods without drinking. They aid themselves in this regard by producing urine that is highly concentrated, thus reducing their loss of water. Some desert mice, alternatively, conserve the water that would be lost in respiration by making it pass through a series of intricate ducts that open into the nasal sinuses, where the air loses moisture as it cools.
According to paragraph 5,all of the following are true of desert animals EXCEPT:
Negative Factual Information Questions否定事实信息题
ASome can survive for long periods without drinking.
BSome speed up their breathing to prevent moisture loss.
CSome have larger appendages than similar species in colder climates.
DSome have smaller bodies than similar species in colder climates.
9
In the desert, many of the plants are annuals, lasting only one season. Some are ephemerals, which arise only after the rare rains and rapidly conclude their cycle before the new drought. They have no need of any particular specialization, other than opportunism and rapid growth. The perennial plants that regularly grow year after year, in contrast, must be much more able to adjust. [■]Normally, they have leathery leaves covered with waxy films to reduce the transpiration and evaporation of internal liquids. [■]Many plants have reduced leaf surfaces, or they have transmuted them into sharp thorns. [■]Some species, such as mosses and lichens, curl their leaves during the dry periods. [■]Other plants have fleshy tissues in which they concentrate and conserve great quantities of reserve water. Still other plants grow only in the proximity of sources or basins of water dispersed in the desert (in oases)or around riverbeds where underground water flows. These plants have extremely long roots, which reach down to the moisture coming from the permanent water table. This is the case for the well-known date palm of the oases in the Sahara and the Middle East. When the water layer is too distant, however, other species live by spreading their roots along the surface in order to enjoy the moisture that condenses during the night but is insufficient to penetrate deeply into the soil.
Look at the four squaresthat indicate where the following sentence could be added to the passage
When exposed to water, they straighten and swell up again in just a few seconds.Insert Text Questions句子插入题
Where would the sentence best fit？Click on a square sentence to the passage.
10
Organisms must be highly specialized to survive in the difficult environment of the desert.
Prose Summary Questions概要小结题
Select 3 answers
ADesert perennials, unlike desert annuals, need specialized physical adaptations for continuous survival in desert environments.
BDesert plants and animals adapt equally well to heat, but animals have to find ways to deal with intense competition from many other species for food and water resources.
CDesert animals have developed adaptations in body dimensions and other physical specializations to prevent the unnecessary loss of water.
DDesert ephemerals complete their growth cycle in only one season and thus grow very rapidly after one of the rare desert rains.
EAnimal behavioral adaptations to heat and drought include reducing activity levels and, if long-distance movement is possible, relocating to areas with more favorable conditions.
FLarge-dimensioned desert species tend to stop their activities during the hottest hours, while smaller species, including birds and flying insects, find shelter under trees and rocks.
