网友您好， 请在下方输入框内输入要搜索的题目：
题目内容
（请给出正确答案）
问答题
Passage 1 Despite the basic biological, chemical, and physical similarities found in all living things, a diversity of life exists not only among and between species but also within every natural population. The phenomenon of diversity has had a long history of study because so many of the variations that exist in nature are visible to the eye. (1) It has been suggested that sexual reproduction became the dominant type of reproduction among organisms because of its inherent advantage of variability, which is the mechanism that enables a species to adjust to changing conditions. New variations are potentially present in genetic differences, but how preponderant a variation becomes in a gene pool depends upon the number of offspring the mutants or variants produce (differential reproduction). (2) It is possible for a genetic novelty (new variation) to spread in time to all members of a population, especially if the novelty enhances the population’s chances for survival in the environment in which it exists. Thus, when a species is introduced into a new habitat, it either adapts to the change by natural selection or by some other evolutionary mechanism or else it eventually dies off. Because each new habitat means new adaptations, habitat changes have been responsible for the millions of different kinds of species and for the heterogeneity within each species. The total number of animal and plant species is estimated at between 2,000,000 and 4,500,000; authoritative estimates of the number of extinct species range from 15,000,000 up to 16,000,000,000. (3)Although the use of classification as a means of producing some kind of order out of this staggering number of different types of organisms appears as early as the book of Genesis—with references to cattle, beasts, fowl, creeping things, trees, etc.—the first scientific attempt at classification is attributed to the Greek philosopher Aristotle, who tried to establish a system that would indicate the relationship of all things to each other. He arranged everything along a scale, or “ladder of nature”, with nonliving things at the bottom; plants were placed below animals, and man was at the top. (4)Other schemes that have been used for grouping species include large anatomical similarities, such as wings or fins, which indicate a natural relationship, and also similarities in reproductive structures. (5) At the present time taxonomy is based on two major assumptions: one is that similar body construction can be used as a criterion for a classification grouping; the other is that, in addition to structural similarities, evolutionary and molecular relationships between organisms can be used as a means for determining classification.
参考答案
参考解析
解析：
暂无解析
更多 “问答题Passage 1 Despite the basic biological, chemical, and physical similarities found in all living things, a diversity of life exists not only among and between species but also within every natural population. The phenomenon of diversity has had a long history of study because so many of the variations that exist in nature are visible to the eye. (1) It has been suggested that sexual reproduction became the dominant type of reproduction among organisms because of its inherent advantage of variability, which is the mechanism that enables a species to adjust to changing conditions. New variations are potentially present in genetic differences, but how preponderant a variation becomes in a gene pool depends upon the number of offspring the mutants or variants produce (differential reproduction). (2) It is possible for a genetic novelty (new variation) to spread in time to all members of a population, especially if the novelty enhances the population’s chances for survival in the environment in which it exists. Thus, when a species is introduced into a new habitat, it either adapts to the change by natural selection or by some other evolutionary mechanism or else it eventually dies off. Because each new habitat means new adaptations, habitat changes have been responsible for the millions of different kinds of species and for the heterogeneity within each species. The total number of animal and plant species is estimated at between 2,000,000 and 4,500,000; authoritative estimates of the number of extinct species range from 15,000,000 up to 16,000,000,000. (3)Although the use of classification as a means of producing some kind of order out of this staggering number of different types of organisms appears as early as the book of Genesis—with references to cattle, beasts, fowl, creeping things, trees, etc.—the first scientific attempt at classification is attributed to the Greek philosopher Aristotle, who tried to establish a system that would indicate the relationship of all things to each other. He arranged everything along a scale, or “ladder of nature”, with nonliving things at the bottom; plants were placed below animals, and man was at the top. (4)Other schemes that have been used for grouping species include large anatomical similarities, such as wings or fins, which indicate a natural relationship, and also similarities in reproductive structures. (5) At the present time taxonomy is based on two major assumptions: one is that similar body construction can be used as a criterion for a classification grouping; the other is that, in addition to structural similarities, evolutionary and molecular relationships between organisms can be used as a means for determining classification.” 相关考题
考题
Which of the following statement is TRUE according to this passage?A．Beijing Hotel has just been opened recently.B．There are too many luxurious things in Beijing Hotel.C．Beijing Hotel will prepare rooms for those that had booked the room.D．Not only foreigners but also native people wanted to book rooms for Games.
考题
The loss of biological diversity has become most spectacularly noticeable in extinction or decline of populations of large and well-known animals.Many animal species have become extinct since the 1700’s, among them the California grizzly bear, the dodo, and the passenger pigeon.Hundreds of other animal species are threatened.In North America, endangered species include the black-footed ferret, the California condor, the desert tortoise, and the whooping crane.Most species in danger of extinction anywhere in the world are suffering from the intrusion (侵入) of human beings.The Asian elephant, for example, has become an endangered species due to the expansion of the human population throughout its range in southern Asia.In Africa, the African elephants are being killed off for their tusks.Monkeys and other primates throughout the world are threatened by hunting, capture for medical use, and the destruction of their habitats.And the rhinoceroses, lions, and other large mammals of the African savanna (grassy plains with scattered trees) compete for land and life with some of the most rapidly growing human populations in the world.The loss of biological diversity is most severe, however, in the tropical rain forests.The forests of the tropics are particularly vulnerable to disturbance because the soils have a low capacity for retaining nutrients.Most of the forests’ nutrient elements are held in the tissues of plants.When loggers and farmers destroy existing plant cover, the nutrients are washed from the land into streams, and the land itself becomes less able to support life.Destruction of these forests destroys the habitat of hundreds, sometimes thousands, of species from such creatures as the howler monkey and indigo macaw, to less visible species of plants, insects, and microbes, many of which are not yet known to science.1.The author points out that species extinction ().A.is most noticeable in North AmericaB.is mainly taking place among large animalsC.quickened with industrialization of the societyD.never took place before the 1700’s2.Which of the following is NOT mentioned with regard to human intrusion?A.Elephants are killed off for their tusksB.Some primates are hunted for medical useC.Growing human population results in the competition for land and life among animalsD.Men live increasingly on animals as their source of food.3.The chief cause of the gradual disappearance of biological diversity is ().A.human crueltyB.human interferenceC.the increase of human populationD.the disappearance of the forests4.In tropical forests，().A.animals live a hard life due to competitionB.a lot of species die out for lack of foodC.rains constitute the major threat to speciesD.a greater number of animals are yet to be known5.It can be inferred that species extinction ().A.proceeds of a faster rate than noticeableB.is the worst among well-known animalsC.is the most severe in AfricaD.is chiefly due to competition among species
考题
共用题干
第二篇Ants Have Big Impact on Environment as "Ecosystem Engineers"Research by the University of Exeter has revealed that ants have a big impact on their local environment as a result of their activity as"ecosystem engineers"and predators.The study,published in the Journal of Animal Ecology,found that ants have two distinct effects on their local environment.Firstly,through moving the soil by nest building activity and by collecting food they affect the level of nutrients in the soil.This can indirectly impact the local populations of many animal groups,from decomposers to species much higher up the food chain.Secondly,they prey on a wide range of other animals,including larger prey which can be attacked by vast numbers of ant workers.Dirk Sanders,an author of the study from the university's Centre for Ecology and Conservation,said, "Ants are very effective predators which thrive in huge numbers.They're also very territorial and very aggressive,defending their resources and territory against other predators.All of this means they have a strong influence on their surrounding area.""In this research,we studied for the first time how big this impact is and the subtleties of it.What we found is that despite being predators,their presence can also lead to an increase in density and diversity of other animal groups.They genuinely play a key role in the local environment,having a big influence on the grassland food web,"Sanders said.The study,carried out in Germany,studied the impact of the presence of different combinations and densities of black garden ants and common red ants,both of which can be found across Europe,including the UK. It found that a low density of ants in an area increased the diversity and density of other animals in the local area,particularly the density of herbivores and decomposers.At higher densities ants had no or the opposite effect,the predation counteracting the positive influence.Dr Frank van Veen,another author on the study,said:"What we find is that the impact of ants on soil nutrient levels has a positive effect on animal groups at low levels,but as the number of ants increases,their predatory impacts have the bigger effect一thereby counteracting the positive influence via ecosystem engineering."Ants are important components of the ecosystem not only because they constitute a great part of the animal biomass but also because they act as ecosystem engineers.Ant biodiversity is incredibly high,and these organisms are highly responsive to human impact,which obviously reduces its richness.However,it is not clear how such disturbance damages the maintenance of ant services to the ecosystem.Ants are important in below ground processes through the alteration of the physical and chemical environment and through their effects on plants,microorganisms,and other soil organisms.What still remains unclear about ants,according to the last paragraph?A:What roles ants play in the ecosystem in which they live.B:How ants affect the animal diversity in a given ecosystem.C:How human activities affect ants' influence on a given ecosystem.D:How ants alter the physical and chemical environment.
考题
Instincts are the natural resources of human behavior,the raw materials of action,feeling,and thought.They are the primary motives and the indispensable instruments of action.But like other natural resources,men's original tendencies must be controlled and redirected,if they are to be frurtfully utilized in the interests of human welfare.There are a number of conditions that make imperative the control of native tendencies.The first of these is intrinsic to the organization of instincts themselves:impulses are stimulated at random and collide with one another.Often one impulse,be it that of curiosity or aggression,can be indulged only at the expense or frustration of many others just as natural,normal,and inevitable.A life is a long-time enterprise and it contains a diversity of desires.If all of these are to receive any measure of fulfillment there must be compromise and adjustment between them;they must all be subjected to some measure of control.A second cause for the control of instinct lies in the fact that people live and have to live together.The close association which is so characteristic of human life is partly attributable to a specific gregarious instinct,partly to the increasing need for cooperation which marks the increasing complexity of civilization.But whatever be its causes,group association makes it necessary that men regulate their impulses and actions with reference to one another.Endowed as human beings are with more or less identical sets of original native desires,the desires of one cannot be freely fulfilled without frequently coming into conflict with the similar desires of others.Still another imperative reason for the control of our instinctive equipment lies in the fact that instincts as such are inadequate to adjust either the individual or the group to contemporary conditions.They were developed in the process of evolution as useful methods for enabling the human animal to cope with a radically different and incomparably simpler environment.While the problems and processes of his life and environment have grown more complex,man's inborn equipment for controlling the world he lives in has,through the long history of civilization,remained practically unchanged.And,finally,so vastly complicated have become the physical and the social machinery of civilized life that it is literally impossible to depend on instincts to adjust us to an environment far different from that to which they were in the process of evolution adapted.In the light of these conditions men have found that if they are to live happily and fruitfully together,certain original tendencies must be stimulated and developed,others weakened,redirected,and modified,and still others,within limits possibly,altogether repressed.
考题
共用题干
第二篇Research by the University of Exeter has revealed that ants have a big impact on their local en-vironment as a result of their activity as"ecosystem engineers"and predators.The study,published in the Journal of Animal Ecology,found that ants have two distinct effects on their local environment.Firstly,through moving of soil by nest building activity and by collecting food they affect the level of nutrients in the soil.This can indirectly impact the local populations of many animal groups, from decomposers to species much higher up the food chain.Secondly,they prey on a wide range of other animals,including larger prey which can be at-tacked by vast numbers of ant workers.Dirk Sanders,an author of the study from the university's Centre for Ecology and Conservation, said:"Ants are very effective predators which thrive in huge numbers.They're also very territorial and very aggressive,defending their resources and territory against other predators.All of this means they have a strong influence on their surrounding area.""In this research,we studied for the first time how big this impact is and the subtleties of it. What we found is that despite being predators,their presence can also lead to an increase in density and diversity of other animal groups.They genuinely play a key role in the local environment,haying a big influence on the grassland food web,"Sanders said.The study,carried out in Germany,studied the impact of the presence of different combinations and densities of black garden ants and common red ants,both species which can be found across Eurone.including in the UK.It found that a low density of ants in an area increased the diversity and density of other animals in the local area,particularly the density of herbivores and decomposers.At higher densities ants had no or the opposite effect,showing that predation is counteracting the positive influence.Dr Frank van Veen,another author on the study,said:"What we find is that the impact of ants on soil nutrient levels has a positive effect on animal groups at low levels,but as the number of ants increases,their predatory impacts have the bigger effect一thereby counteracting the positive influence via ecosystem engineering."Ants are important components of ecosystems not only because they constitute a great part of the animal biomass but also because they act as ecosystem engineers.Ant biodiversity is incredibly high and these organisms are highly responsive to human impact,which obviously reduces its richness. However,it is not clear how such disturbance damages the maintenance of ant services to the ecosystem.Ants are important in below ground processes through the alteration of the physical and chemical environment and through their effects on plants,microorganisms,and other soil organisms.What still remains unclear about ants,according to the last paragraph?A:What roles do ants play in the ecosystem in which they live?B:How do ants affect the animal diversity in a given ecosystem?C:How do human activities affect ants' influence on a given ecosystem?D:How do ants alter the physical and chemical environment?
考题
共用题干
第二篇Research by the University of Exeter has revealed that ants have a big impact on their local en-vironment as a result of their activity as"ecosystem engineers"and predators.The study,published in the Journal of Animal Ecology,found that ants have two distinct effects on their local environment.Firstly,through moving of soil by nest building activity and by collecting food they affect the level of nutrients in the soil.This can indirectly impact the local populations of many animal groups, from decomposers to species much higher up the food chain.Secondly,they prey on a wide range of other animals,including larger prey which can be at-tacked by vast numbers of ant workers.Dirk Sanders,an author of the study from the university's Centre for Ecology and Conservation, said:"Ants are very effective predators which thrive in huge numbers.They're also very territorial and very aggressive,defending their resources and territory against other predators.All of this means they have a strong influence on their surrounding area.""In this research,we studied for the first time how big this impact is and the subtleties of it. What we found is that despite being predators,their presence can also lead to an increase in density and diversity of other animal groups.They genuinely play a key role in the local environment,haying a big influence on the grassland food web,"Sanders said.The study,carried out in Germany,studied the impact of the presence of different combinations and densities of black garden ants and common red ants,both species which can be found across Eurone.including in the UK.It found that a low density of ants in an area increased the diversity and density of other animals in the local area,particularly the density of herbivores and decomposers.At higher densities ants had no or the opposite effect,showing that predation is counteracting the positive influence.Dr Frank van Veen,another author on the study,said:"What we find is that the impact of ants on soil nutrient levels has a positive effect on animal groups at low levels,but as the number of ants increases,their predatory impacts have the bigger effect一thereby counteracting the positive influence via ecosystem engineering."Ants are important components of ecosystems not only because they constitute a great part of the animal biomass but also because they act as ecosystem engineers.Ant biodiversity is incredibly high and these organisms are highly responsive to human impact,which obviously reduces its richness. However,it is not clear how such disturbance damages the maintenance of ant services to the ecosystem.Ants are important in below ground processes through the alteration of the physical and chemical environment and through their effects on plants,microorganisms,and other soil organisms.As predators,ants_________.A:prey on small as well as large animalsB:collect nutritious food from the soilC:collect food as decomposersD:prey on species much higher up the food chain
考题
共用题干
Ants Have Big Impact on Environment as“Ecosystem Engineers”Research by the University of Exeter has revealed that ants have a big impact on their local environment as a result of their activity as“ecosystem engineers”and predators. The study,published in the Journal of Animal Ecology,found that ants have two distinct effects on their local environment.Firstly,through moving of soil by nest building activity and by collecting food they af-fect the level of nutrients in the soil. This can indirectly impact the local populations of many animal groups,from decomposers to species much higher up the food chain.Secondly,they prey on a wide range of other animals,including larger prey which can be attacked by vast numbers of ant workers.Dirk Sanders,an author of the study from the university's Centre for Ecology and Con-servation,said:“Ants are very effective predators which thrive in huge numbers. They're al-so very territorial and very aggressive,defending their resources and territory against other predators. All of this means they have a strong influence on their surrounding area.”“In this research,we studied for the first time how big this impact is and the subtleties of it. What we found is that despite being predators,their presence can also lead to an increase in density and diversity of other animal groups. They genuinely play a key role in the local environment,having a big influence on the grassland food web,”Sanders said.The study,carried out in Germany,studied the impact of the presence of different combinations and densities of black garden ants and common red ants,both species which can be found across Europe,including in the UK.It found that a low density of ants in an area increased the diversity and density of other animals in the local area,particularly the density of herbivores and decomposers. At higher densities ants had no or the opposite effect,showing that predation is counteracting the positive influence.Dr Frank van Veen,another author on the study,said:“What we find is that the impact of ants on soil nutrient levels has a positive effect on animal groups at low levels,but as the number of ants increases,their predatory impacts have the bigger effect一thereby counteracting the positive influence via ecosystem engineering.”Ants are important components of ecosystems not only because they constitute a great part of the animal biomass but also because they act as ecosystem engineers. Ant biodiversity is incredibly high and these organisms are highly responsive to human impact,which obviously reduces its richness. However,it is not clear how such disturbance damages the maintenance of ant services to the ecosystem. Ants are important in below ground processes through the alteration of the physical and chemical environment and through their effects on plants,microorganisms,and other soil organisms.As predators,ants______.A:prey on small as well as large animalsB: collect nutritious food from the soilC: collect food as decomposersD: prey on species much higher up the food chain
考题
共用题干
Ants Have Big Impact on Environment as“Ecosystem Engineers”Research by the University of Exeter has revealed that ants have a big impact on their local environment as a result of their activity as“ecosystem engineers”and predators. The study,published in the Journal of Animal Ecology,found that ants have two distinct effects on their local environment.Firstly,through moving of soil by nest building activity and by collecting food they af-fect the level of nutrients in the soil. This can indirectly impact the local populations of many animal groups,from decomposers to species much higher up the food chain.Secondly,they prey on a wide range of other animals,including larger prey which can be attacked by vast numbers of ant workers.Dirk Sanders,an author of the study from the university's Centre for Ecology and Con-servation,said:“Ants are very effective predators which thrive in huge numbers. They're al-so very territorial and very aggressive,defending their resources and territory against other predators. All of this means they have a strong influence on their surrounding area.”“In this research,we studied for the first time how big this impact is and the subtleties of it. What we found is that despite being predators,their presence can also lead to an increase in density and diversity of other animal groups. They genuinely play a key role in the local environment,having a big influence on the grassland food web,”Sanders said.The study,carried out in Germany,studied the impact of the presence of different combinations and densities of black garden ants and common red ants,both species which can be found across Europe,including in the UK.It found that a low density of ants in an area increased the diversity and density of other animals in the local area,particularly the density of herbivores and decomposers. At higher densities ants had no or the opposite effect,showing that predation is counteracting the positive influence.Dr Frank van Veen,another author on the study,said:“What we find is that the impact of ants on soil nutrient levels has a positive effect on animal groups at low levels,but as the number of ants increases,their predatory impacts have the bigger effect一thereby counteracting the positive influence via ecosystem engineering.”Ants are important components of ecosystems not only because they constitute a great part of the animal biomass but also because they act as ecosystem engineers. Ant biodiversity is incredibly high and these organisms are highly responsive to human impact,which obviously reduces its richness. However,it is not clear how such disturbance damages the maintenance of ant services to the ecosystem. Ants are important in below ground processes through the alteration of the physical and chemical environment and through their effects on plants,microorganisms,and other soil organisms.What still remains unclear about ants,according to the last paragraph?A: What roles do ants play in the ecosystem in which they live?B: How do ants affect the animal diversity in a given ecosystem?C: How do human activities affect ants'influence on a given ecosystem?D: How do ants alter the physical and chemical environment?
考题
共用题干
To Survive or to Vanish1.Over 3.6 billion years ago,the first creature was born in the world.Since then,the earth started its era with life.The history of life on earth has been a history of interaction between living things and their surroundings.To a large extent,the physical form and the habits of the earth's vegetation and its animal life have been molded by the environment. Considering the whole span of earthly time,the opposite effect,in which life actually modifies its surroundings,has been relatively slight. Only in the present century has one species一man acquired significant power to alter the nature of his world.2.During the past 25 years,this power has not only become increasingly great but it has changed in character. The most alarming of all man's assaults upon the environment is the contamination of air,earth,rivers,and sea with dangerous and even lethal materials. This pollution is for the most part irrecoverable.In this now universal contamination of the environment,chemicals are the sinister partners of radiation in changing the very nature of the world the very nature of its life. Chemicals sprayed on croplands or forests or gardens lie long in soil,entering into living organisms, passing from one to another in a chain of poisoning and death.Or they pass mysteriously by underground streams until they emerge and combine into new forms that kill vegetation,sicken cattle,and work unknown harm on those who drink from once pure wells."Man can hardly even recognize the devils of his own creation,"as a scientist has said.3.Hundreds of millions of years have passed before the globe produced the life that now inhabits the earth.Given time not in years but in millennia life adjusts,and a balance has been reached.But in the modern world there is no time.4.The quick steps of change follows the impetuous pace of man rather than the deliberate pace of nature.Radiation is now the unnatural creation of man's tampering with the atom.The chemicals are the synthetic creations of man's inventive mind,having no counterparts in nature.5.To survive these chemicals would require not merely the years of one man's life but the life of generations.And even this,were it by some miracle possible,would be futile,for the new chemicals come from our laboratories in an endless stream;almost five hundred annually find their way into actual use in the United States alone.Among them are many that are used in man's war against nature.Since the mid l940's over 200 basic chemicals have been created for use in killing insects,weeds,and other organisms described as"pests".6.It is not my contention that chemical insecticides must never he used.I do contend that we have put poisonous and biologically potent chemicals indiscriminately into the hands of persons largely or wholly ignorant of their potentials for harm. We have subjected enormous numbers of people to contact with these poisons,without their consent and often without their knowledge.I contend,furthermore,that we have allowed these chemicals to be used with little or no advance investigation of their effect on soil,water,wildlife,and man himself. Future generations are unlikely to forgive our lack of concern for the integrity of the natural world that supports all life.Human's pollution on nature is for the most part_______.A:man's tampering with the atomB:enormous numbers of people to contact with these poisonsC:the integrity of the natural world that supports all lifeD:inventiveE:irrecoverableF:relatively slight
考题
共用题干
To Survive or to Vanish1.Over 3.6 billion years ago,the first creature was born in the world.Since then,the earth started its era with life.The history of life on earth has been a history of interaction between living things and their surroundings.To a large extent,the physical form and the habits of the earth's vegetation and its animal life have been molded by the environment. Considering the whole span of earthly time,the opposite effect,in which life actually modifies its surroundings,has been relatively slight. Only in the present century has one species一man acquired significant power to alter the nature of his world.2.During the past 25 years,this power has not only become increasingly great but it has changed in character. The most alarming of all man's assaults upon the environment is the contamination of air,earth,rivers,and sea with dangerous and even lethal materials. This pollution is for the most part irrecoverable.In this now universal contamination of the environment,chemicals are the sinister partners of radiation in changing the very nature of the world the very nature of its life. Chemicals sprayed on croplands or forests or gardens lie long in soil,entering into living organisms, passing from one to another in a chain of poisoning and death.Or they pass mysteriously by underground streams until they emerge and combine into new forms that kill vegetation,sicken cattle,and work unknown harm on those who drink from once pure wells."Man can hardly even recognize the devils of his own creation,"as a scientist has said.3.Hundreds of millions of years have passed before the globe produced the life that now inhabits the earth.Given time not in years but in millennia life adjusts,and a balance has been reached.But in the modern world there is no time.4.The quick steps of change follows the impetuous pace of man rather than the deliberate pace of nature.Radiation is now the unnatural creation of man's tampering with the atom.The chemicals are the synthetic creations of man's inventive mind,having no counterparts in nature.5.To survive these chemicals would require not merely the years of one man's life but the life of generations.And even this,were it by some miracle possible,would be futile,for the new chemicals come from our laboratories in an endless stream;almost five hundred annually find their way into actual use in the United States alone.Among them are many that are used in man's war against nature.Since the mid l940's over 200 basic chemicals have been created for use in killing insects,weeds,and other organisms described as"pests".6.It is not my contention that chemical insecticides must never he used.I do contend that we have put poisonous and biologically potent chemicals indiscriminately into the hands of persons largely or wholly ignorant of their potentials for harm. We have subjected enormous numbers of people to contact with these poisons,without their consent and often without their knowledge.I contend,furthermore,that we have allowed these chemicals to be used with little or no advance investigation of their effect on soil,water,wildlife,and man himself. Future generations are unlikely to forgive our lack of concern for the integrity of the natural world that supports all life.The effect of life modifying its surroundings has been_______.A:man's tampering with the atomB:enormous numbers of people to contact with these poisonsC:the integrity of the natural world that supports all lifeD:inventiveE:irrecoverableF:relatively slight
考题
共用题干
To Survive or to Vanish1.Over 3.6 billion years ago,the first creature was born in the world.Since then,the earth started its era with life.The history of life on earth has been a history of interaction between living things and their surroundings.To a large extent,the physical form and the habits of the earth's vegetation and its animal life have been molded by the environment. Considering the whole span of earthly time,the opposite effect,in which life actually modifies its surroundings,has been relatively slight. Only in the present century has one species一man acquired significant power to alter the nature of his world.2.During the past 25 years,this power has not only become increasingly great but it has changed in character. The most alarming of all man's assaults upon the environment is the contamination of air,earth,rivers,and sea with dangerous and even lethal materials. This pollution is for the most part irrecoverable.In this now universal contamination of the environment,chemicals are the sinister partners of radiation in changing the very nature of the world the very nature of its life. Chemicals sprayed on croplands or forests or gardens lie long in soil,entering into living organisms, passing from one to another in a chain of poisoning and death.Or they pass mysteriously by underground streams until they emerge and combine into new forms that kill vegetation,sicken cattle,and work unknown harm on those who drink from once pure wells."Man can hardly even recognize the devils of his own creation,"as a scientist has said.3.Hundreds of millions of years have passed before the globe produced the life that now inhabits the earth.Given time not in years but in millennia life adjusts,and a balance has been reached.But in the modern world there is no time.4.The quick steps of change follows the impetuous pace of man rather than the deliberate pace of nature.Radiation is now the unnatural creation of man's tampering with the atom.The chemicals are the synthetic creations of man's inventive mind,having no counterparts in nature.5.To survive these chemicals would require not merely the years of one man's life but the life of generations.And even this,were it by some miracle possible,would be futile,for the new chemicals come from our laboratories in an endless stream;almost five hundred annually find their way into actual use in the United States alone.Among them are many that are used in man's war against nature.Since the mid l940's over 200 basic chemicals have been created for use in killing insects,weeds,and other organisms described as"pests".6.It is not my contention that chemical insecticides must never he used.I do contend that we have put poisonous and biologically potent chemicals indiscriminately into the hands of persons largely or wholly ignorant of their potentials for harm. We have subjected enormous numbers of people to contact with these poisons,without their consent and often without their knowledge.I contend,furthermore,that we have allowed these chemicals to be used with little or no advance investigation of their effect on soil,water,wildlife,and man himself. Future generations are unlikely to forgive our lack of concern for the integrity of the natural world that supports all life.Paragraph 1_______A:Man should be cautious in chemical use.B:It takes generations for mankind to adapt themselves to the chemicals.C:Chemicals are human's inventionD:Human's power increases and has changed its character in the past quarter century.E:The new change in the relationship between earth and its creature一human's power playing a greater role in changing the worldF: Modern world gives no time for nature to adjust to human.
考题
共用题干
To Survive or to Vanish1.Over 3.6 billion years ago,the first creature was born in the world.Since then,the earth started its era with life.The history of life on earth has been a history of interaction between living things and their surroundings.To a large extent,the physical form and the habits of the earth's vegetation and its animal life have been molded by the environment. Considering the whole span of earthly time,the opposite effect,in which life actually modifies its surroundings,has been relatively slight. Only in the present century has one species一man acquired significant power to alter the nature of his world.2.During the past 25 years,this power has not only become increasingly great but it has changed in character. The most alarming of all man's assaults upon the environment is the contamination of air,earth,rivers,and sea with dangerous and even lethal materials. This pollution is for the most part irrecoverable.In this now universal contamination of the environment,chemicals are the sinister partners of radiation in changing the very nature of the world the very nature of its life. Chemicals sprayed on croplands or forests or gardens lie long in soil,entering into living organisms, passing from one to another in a chain of poisoning and death.Or they pass mysteriously by underground streams until they emerge and combine into new forms that kill vegetation,sicken cattle,and work unknown harm on those who drink from once pure wells."Man can hardly even recognize the devils of his own creation,"as a scientist has said.3.Hundreds of millions of years have passed before the globe produced the life that now inhabits the earth.Given time not in years but in millennia life adjusts,and a balance has been reached.But in the modern world there is no time.4.The quick steps of change follows the impetuous pace of man rather than the deliberate pace of nature.Radiation is now the unnatural creation of man's tampering with the atom.The chemicals are the synthetic creations of man's inventive mind,having no counterparts in nature.5.To survive these chemicals would require not merely the years of one man's life but the life of generations.And even this,were it by some miracle possible,would be futile,for the new chemicals come from our laboratories in an endless stream;almost five hundred annually find their way into actual use in the United States alone.Among them are many that are used in man's war against nature.Since the mid l940's over 200 basic chemicals have been created for use in killing insects,weeds,and other organisms described as"pests".6.It is not my contention that chemical insecticides must never he used.I do contend that we have put poisonous and biologically potent chemicals indiscriminately into the hands of persons largely or wholly ignorant of their potentials for harm. We have subjected enormous numbers of people to contact with these poisons,without their consent and often without their knowledge.I contend,furthermore,that we have allowed these chemicals to be used with little or no advance investigation of their effect on soil,water,wildlife,and man himself. Future generations are unlikely to forgive our lack of concern for the integrity of the natural world that supports all life.Paragraph 5_______A:Man should be cautious in chemical use.B:It takes generations for mankind to adapt themselves to the chemicals.C:Chemicals are human's inventionD:Human's power increases and has changed its character in the past quarter century.E:The new change in the relationship between earth and its creature一human's power playing a greater role in changing the worldF: Modern world gives no time for nature to adjust to human.
考题
共用题干
Ecosystem1. The word “ecosystem” is short for ecological（生态的）system. An ecosystem is where living creatures expand within a given area. You can say that an ecosystem is the natural environment where biological organisms（生物）such as plants,animals and humans co-exist in this world. So naturally that includes you and me. Yes,we are all members of an ecosystem!2 .There are different kinds of ecosystems depending on the type of surface or environ-ment. Most are naturally made such as the ocean or lake and the desert or rainforest.Some are man-made or artificial to encourage co-habitation（同居）between living and non-living things in a monitored environment,such as a zoo or garden.3 .Plants make up the biggest group of biological creatures within an ecosystem,and that's because they are the natural food producers for everyone. Plants raised in the earth need air and collect sunlight to help them grow. When they grow,the plants and its fruits or flowers eventually become a source of food to animals,microorganisms（微生物）and even hu- mans,of course. Food is then converted to energy for the rest of us to function,and this hap-pens in a never-ending cycle until the living creatures die and break up back in the earth.4 .Ecosystems are the basis of survival for all living things.We depend on plants and ani-mals for food. In order for us to exist,we need to grow and care about other organisms. We also need to care for the non-living things within our environment like our air and water so we can continue living as a population. Since plants,animals and humans are all of various species（物种）,we all play a role in maintaining the ecosystem.5 .To preserve our ecosystems,we should stop using too much energy,which happens when we consume more than our share of resources. Humans should not disturb the natural habitat（栖息地）of plants and animals,and allow them to grow healthily for the cycle to con-tinue. Too many people in a habitat can mean displacement（搬迁）: imagine being thrown out of your home because there is no more space for everyone. Worse,overpopulation can also ru- in the environment and cause destruction of existing plants and animals.Plants,animals and humans are all effective in______.A: our share of resourcesB: a biological creatureC: a given areaD: the maintenance of the ecosystemE: the source of foodF: various species
考题
共用题干
Ecosystem1. The word “ecosystem” is short for ecological（生态的）system. An ecosystem is where living creatures expand within a given area. You can say that an ecosystem is the natural environment where biological organisms（生物）such as plants,animals and humans co-exist in this world. So naturally that includes you and me. Yes,we are all members of an ecosystem!2 .There are different kinds of ecosystems depending on the type of surface or environ-ment. Most are naturally made such as the ocean or lake and the desert or rainforest.Some are man-made or artificial to encourage co-habitation（同居）between living and non-living things in a monitored environment,such as a zoo or garden.3 .Plants make up the biggest group of biological creatures within an ecosystem,and that's because they are the natural food producers for everyone. Plants raised in the earth need air and collect sunlight to help them grow. When they grow,the plants and its fruits or flowers eventually become a source of food to animals,microorganisms（微生物）and even hu- mans,of course. Food is then converted to energy for the rest of us to function,and this hap-pens in a never-ending cycle until the living creatures die and break up back in the earth.4 .Ecosystems are the basis of survival for all living things.We depend on plants and ani-mals for food. In order for us to exist,we need to grow and care about other organisms. We also need to care for the non-living things within our environment like our air and water so we can continue living as a population. Since plants,animals and humans are all of various species（物种）,we all play a role in maintaining the ecosystem.5 .To preserve our ecosystems,we should stop using too much energy,which happens when we consume more than our share of resources. Humans should not disturb the natural habitat（栖息地）of plants and animals,and allow them to grow healthily for the cycle to con-tinue. Too many people in a habitat can mean displacement（搬迁）: imagine being thrown out of your home because there is no more space for everyone. Worse,overpopulation can also ru- in the environment and cause destruction of existing plants and animals.In an ecosystem,plants,animals and humans live together in______.A: our share of resourcesB: a biological creatureC: a given areaD: the maintenance of the ecosystemE: the source of foodF: various species
考题
共用题干
Ecosystem1. The word “ecosystem” is short for ecological（生态的）system. An ecosystem is where living creatures expand within a given area. You can say that an ecosystem is the natural environment where biological organisms（生物）such as plants,animals and humans co-exist in this world. So naturally that includes you and me. Yes,we are all members of an ecosystem!2 .There are different kinds of ecosystems depending on the type of surface or environ-ment. Most are naturally made such as the ocean or lake and the desert or rainforest.Some are man-made or artificial to encourage co-habitation（同居）between living and non-living things in a monitored environment,such as a zoo or garden.3 .Plants make up the biggest group of biological creatures within an ecosystem,and that's because they are the natural food producers for everyone. Plants raised in the earth need air and collect sunlight to help them grow. When they grow,the plants and its fruits or flowers eventually become a source of food to animals,microorganisms（微生物）and even hu- mans,of course. Food is then converted to energy for the rest of us to function,and this hap-pens in a never-ending cycle until the living creatures die and break up back in the earth.4 .Ecosystems are the basis of survival for all living things.We depend on plants and ani-mals for food. In order for us to exist,we need to grow and care about other organisms. We also need to care for the non-living things within our environment like our air and water so we can continue living as a population. Since plants,animals and humans are all of various species（物种）,we all play a role in maintaining the ecosystem.5 .To preserve our ecosystems,we should stop using too much energy,which happens when we consume more than our share of resources. Humans should not disturb the natural habitat（栖息地）of plants and animals,and allow them to grow healthily for the cycle to con-tinue. Too many people in a habitat can mean displacement（搬迁）: imagine being thrown out of your home because there is no more space for everyone. Worse,overpopulation can also ru- in the environment and cause destruction of existing plants and animals.Paragraph 2_________A: What Can We Do to Help Protect Ecosystems?B: What Are Different types of Ecosystems?C: What Is an Ecosystem?D: What Destroys Ecosystems?E: How Does an Ecosystem Work?F: Why Are Ecosystems Emportant?
考题
共用题干
第三篇Ants Have Big Impact on Environment as " Ecosystem Engineers"Research by the University of Exeter has revealed that ants have a big impact on their local environment as a result of their activity as"ecosystem engineers"and predators.The study,published in the Journal of Animal Ecology,found that ants have two distinct effects on their local environment?Firstly.throuah moving the soil by nest building activity and by collecting food they affect the level ofnutrients in the soil.This can indirectly impact the local populations of many animal groups,from decomposers to species much higher up the food chain.Secondly,they prey on a wide range of other animals,including larger prey which can be attacked by vast numbers of ant workers.Dirk Sanders,an author of the study from the university's Centre for Ecology and Conservation,said, "Ants are very effective predators which thrive in huge numbers.They're also very territorial and very ag- gressive,defending their resources and territory against other predators.All of this means they have a strong influence on their surrounding area.""In this research,we studied for the first time how big this impact is and the subtleties of it.What we found is that despite being predators,their presence can also lead to an increase in density and diversity of other animal groups.They genuinely play a key role in the local environment,having a big influence on the grassland food web,"Sanders said.The study,carried out in Germany,studied the impact of the presence of different combinations and den- sities of black garden ants and common red ants,both of which can be found across Europe,including the UK. It found that a low density of ants in an area increased the diversity and density of other animals in the local area,particularly the density of herbivores and decomposers.At higher densities ants had no or the op-posite effect,the predation counteracting the positive influence.Dr Frank van Veen,another author on the study,said:"What we find is that the impact of ants on soil nutrient levels has a positive effect on animal groups at low levels,but as the number of ants increases,their predatory impacts have the bigger effect一thereby counteracting the positive influence via ecosystemengineering.Ants are important components of the ecosystem not only because they constitute a great part of the ani--mal biomass but also because they act as ecosystem engineers.Ant biodiversity is incredibly high and these organisms are highly responsive to human impact,which obviously reduces its richness.However,it is not clear how such disturbance damages the maintenance of ant services to the ecosystem.Ants are important in below ground processes through the alteration of the physical and chemical environment and through their effects on plants,microorganisms,and other soil organisms.What still remains unclear about ants,according to the last paragraph?A:What roles ants play in the ecosystem in which they live.B:How ants affect the animal diversity in a given ecosystem.C:How human activities affect ants'influence on a given ecosystem.D:How ants alter the physical and chemical environment.
考题
共用题干
Ecosystem1. The word “ecosystem” is short for ecological（生态的）system. An ecosystem is where living creatures expand within a given area. You can say that an ecosystem is the natural environment where biological organisms（生物）such as plants,animals and humans co-exist in this world. So naturally that includes you and me. Yes,we are all members of an ecosystem!2 .There are different kinds of ecosystems depending on the type of surface or environ-ment. Most are naturally made such as the ocean or lake and the desert or rainforest.Some are man-made or artificial to encourage co-habitation（同居）between living and non-living things in a monitored environment,such as a zoo or garden.3 .Plants make up the biggest group of biological creatures within an ecosystem,and that's because they are the natural food producers for everyone. Plants raised in the earth need air and collect sunlight to help them grow. When they grow,the plants and its fruits or flowers eventually become a source of food to animals,microorganisms（微生物）and even hu- mans,of course. Food is then converted to energy for the rest of us to function,and this hap-pens in a never-ending cycle until the living creatures die and break up back in the earth.4 .Ecosystems are the basis of survival for all living things.We depend on plants and ani-mals for food. In order for us to exist,we need to grow and care about other organisms. We also need to care for the non-living things within our environment like our air and water so we can continue living as a population. Since plants,animals and humans are all of various species（物种）,we all play a role in maintaining the ecosystem.5 .To preserve our ecosystems,we should stop using too much energy,which happens when we consume more than our share of resources. Humans should not disturb the natural habitat（栖息地）of plants and animals,and allow them to grow healthily for the cycle to con-tinue. Too many people in a habitat can mean displacement（搬迁）: imagine being thrown out of your home because there is no more space for everyone. Worse,overpopulation can also ru- in the environment and cause destruction of existing plants and animals.Plants are essential in an ecosystem because to other living creatures they are______.A: our share of resourcesB: a biological creatureC: a given areaD: the maintenance of the ecosystemE: the source of foodF: various species
考题
共用题干
第二篇The Book of LifeSo far, scientists have named about 1.8 million living species（物种）,and that's just a small part of what probably exists on Earth.With so many plants,animals,and other creatures covering the planet,it can be tough to figure out what type of spider is moving up your leg or what kind of bird is flying by.A soon-to-be-launched Web site mighit help. An international team of researchers has announced the creation of a Web-based Encyclopedia（百科全书）of Life(EoL).The project aims to catalog every species on Earth in a single,easy-to-use referenice guide.To get the encyclopedia started,the creators will use information from scientific databases（数据库）that already exist. And eventually , in special sections of the site , nonscientists with specialized（专门的） knowledge will get to join in Bird-watchers,for example,will be able to input which birds they'ye seen and where.The technology for this kind of tool has only recently become available.As the EoL develops,you might find it useful for school projects.The site will feature special pages for kids who are studying ecosystems（生态系统）in their neighborhoods. To make sure the encyclopedia is accurate,scientists will review much of the information added to it.People who visit the site will be able tochoose to leave out pages that haven't been reviewed.Another convenient feature of the EoL is that you'11 be able to pick the level of detail you see to match your interests,age,and current knowledge.If you wanted to learn about bears for a science class report,for example,you could use the"novice"setting to get basic information about the animals.On the"expert" setting,on the other hand,you could get much more detailed information about the history,literature,andexploration of bears.It now takes years for scientists to collect all the data they need to describe and analyze species.The creators of the Encyclopedia of Life hope that their new tool will speed that process.The goal of the creation of the EoL is to________.A:collect enough data to analyze the living species on EarthB:enlarge an existing Web site of the living species on EarthC:work out an easy-to-use catalog of every living species on EarthD:add new information to the existing databases of the living species on Earth
考题
共用题干
Ecosystem1 The word " ecosystem" is short for ecological（生态的）system. An ecosystem is where living crea- tures expand within a given area.You can say that an ecosystem is the natural environment where biologicalorganisms（生物）such as plants,animals and humans co-exist in this world. So naturally that includes you and mne.Yes,we are all members of an ecosystem!2 There are different kinds of ecosystems depending on the type of suiface or environment. Most are naturally made 5uch as the ocean or lake and the desert or rainforest.Some are man-made or artificial to en- courage co-habitation（共居）between living and non-living things in a monitored environment,such as azoo or garden.3 Plants make up the biggest group of biological creatures within an ecosystem,and that's because they are the natural food producers for everyone.Plants raised in the earth need air and collect sunlight to help them grow.When they grow,the plants and their加its or flowers eventually become a source of food to animals,microorganisms (微生物）and even humans, of course. Food is then converted to energy for the rest of us to function,and this happens in a never-ending cycle until the living creatures die and break up back in the earth.4 Ecosystems are the basis of survival for all living things.We depend on plants and animals for food. In order for us to exist,we need to grow and care about other organisms.We also need tO care for the non一living things within our environment like our air and water so we can continue living as a population.Since plants, animals and humans are all of various species（物种）,we all play a role in maintaining the ecosystem.5 To preserve our ecosystems,we should stop using too much energy,which happens汕en we consume more than our share of resources. Humans should not disturb the natural habitat（栖息地）of plants and animals, and should allow them to grow healthily for the cycle to continue.Too many people in a habitat can mean dis- placement（搬迁）:imagine being thrown out of your home because there is no more space for everyone. Worse,overpopulation can also ruin the environment and cause destruction of existing plants and animals. Paragraph 3_______A: What Can We Do to Help Protect Ecosystems?B:What Are Different Types of Ecosystems？ C:What Is an Ecosystem？D: What Destroys Ecosystems? E:How does an Ecosystem Work?F: Why Are Ecosystems Important？
考题
共用题干
Ecosystem1 The word " ecosystem" is short for ecological（生态的）system. An ecosystem is where living crea- tures expand within a given area.You can say that an ecosystem is the natural environment where biologicalorganisms（生物）such as plants,animals and humans co-exist in this world. So naturally that includes you and mne.Yes,we are all members of an ecosystem!2 There are different kinds of ecosystems depending on the type of suiface or environment. Most are naturally made 5uch as the ocean or lake and the desert or rainforest.Some are man-made or artificial to en- courage co-habitation（共居）between living and non-living things in a monitored environment,such as azoo or garden.3 Plants make up the biggest group of biological creatures within an ecosystem,and that's because they are the natural food producers for everyone.Plants raised in the earth need air and collect sunlight to help them grow.When they grow,the plants and their加its or flowers eventually become a source of food to animals,microorganisms (微生物）and even humans, of course. Food is then converted to energy for the rest of us to function,and this happens in a never-ending cycle until the living creatures die and break up back in the earth.4 Ecosystems are the basis of survival for all living things.We depend on plants and animals for food. In order for us to exist,we need to grow and care about other organisms.We also need tO care for the non一living things within our environment like our air and water so we can continue living as a population.Since plants, animals and humans are all of various species（物种）,we all play a role in maintaining the ecosystem.5 To preserve our ecosystems,we should stop using too much energy,which happens汕en we consume more than our share of resources. Humans should not disturb the natural habitat（栖息地）of plants and animals, and should allow them to grow healthily for the cycle to continue.Too many people in a habitat can mean dis- placement（搬迁）:imagine being thrown out of your home because there is no more space for everyone. Worse,overpopulation can also ruin the environment and cause destruction of existing plants and animals.In an ecosystem,plants,animals and humans live together in________.A:our share of resoureesB:a biological creatureC:a given areaD:the maintenance of the ecosystemE:the source of foodF:various species
考题
共用题干
Ecosystem1 The word " ecosystem" is short for ecological（生态的）system. An ecosystem is where living crea- tures expand within a given area.You can say that an ecosystem is the natural environment where biologicalorganisms（生物）such as plants,animals and humans co-exist in this world. So naturally that includes you and mne.Yes,we are all members of an ecosystem!2 There are different kinds of ecosystems depending on the type of suiface or environment. Most are naturally made 5uch as the ocean or lake and the desert or rainforest.Some are man-made or artificial to en- courage co-habitation（共居）between living and non-living things in a monitored environment,such as azoo or garden.3 Plants make up the biggest group of biological creatures within an ecosystem,and that's because they are the natural food producers for everyone.Plants raised in the earth need air and collect sunlight to help them grow.When they grow,the plants and their加its or flowers eventually become a source of food to animals,microorganisms (微生物）and even humans, of course. Food is then converted to energy for the rest of us to function,and this happens in a never-ending cycle until the living creatures die and break up back in the earth.4 Ecosystems are the basis of survival for all living things.We depend on plants and animals for food. In order for us to exist,we need to grow and care about other organisms.We also need tO care for the non一living things within our environment like our air and water so we can continue living as a population.Since plants, animals and humans are all of various species（物种）,we all play a role in maintaining the ecosystem.5 To preserve our ecosystems,we should stop using too much energy,which happens汕en we consume more than our share of resources. Humans should not disturb the natural habitat（栖息地）of plants and animals, and should allow them to grow healthily for the cycle to continue.Too many people in a habitat can mean dis- placement（搬迁）:imagine being thrown out of your home because there is no more space for everyone. Worse,overpopulation can also ruin the environment and cause destruction of existing plants and animals.Plants,animals and humans are all effective in________.A:our share of resoureesB:a biological creatureC:a given areaD:the maintenance of the ecosystemE:the source of foodF:various species
考题
共用题干
Ecosystem1 The word " ecosystem" is short for ecological（生态的）system. An ecosystem is where living crea- tures expand within a given area.You can say that an ecosystem is the natural environment where biologicalorganisms（生物）such as plants,animals and humans co-exist in this world. So naturally that includes you and mne.Yes,we are all members of an ecosystem!2 There are different kinds of ecosystems depending on the type of suiface or environment. Most are naturally made 5uch as the ocean or lake and the desert or rainforest.Some are man-made or artificial to en- courage co-habitation（共居）between living and non-living things in a monitored environment,such as azoo or garden.3 Plants make up the biggest group of biological creatures within an ecosystem,and that's because they are the natural food producers for everyone.Plants raised in the earth need air and collect sunlight to help them grow.When they grow,the plants and their加its or flowers eventually become a source of food to animals,microorganisms (微生物）and even humans, of course. Food is then converted to energy for the rest of us to function,and this happens in a never-ending cycle until the living creatures die and break up back in the earth.4 Ecosystems are the basis of survival for all living things.We depend on plants and animals for food. In order for us to exist,we need to grow and care about other organisms.We also need tO care for the non一living things within our environment like our air and water so we can continue living as a population.Since plants, animals and humans are all of various species（物种）,we all play a role in maintaining the ecosystem.5 To preserve our ecosystems,we should stop using too much energy,which happens汕en we consume more than our share of resources. Humans should not disturb the natural habitat（栖息地）of plants and animals, and should allow them to grow healthily for the cycle to continue.Too many people in a habitat can mean dis- placement（搬迁）:imagine being thrown out of your home because there is no more space for everyone. Worse,overpopulation can also ruin the environment and cause destruction of existing plants and animals.Plants are essential in an ecosystem because to other living creatures they are___.A:our share of resoureesB:a biological creatureC:a given areaD:the maintenance of the ecosystemE:the source of foodF:various species
考题
问答题Passage 1 Despite the basic biological, chemical, and physical similarities found in all living things, a diversity of life exists not only among and between species but also within every natural population. The phenomenon of diversity has had a long history of study because so many of the variations that exist in nature are visible to the eye. (1) It has been suggested that sexual reproduction became the dominant type of reproduction among organisms because of its inherent advantage of variability, which is the mechanism that enables a species to adjust to changing conditions. New variations are potentially present in genetic differences, but how preponderant a variation becomes in a gene pool depends upon the number of offspring the mutants or variants produce (differential reproduction). (2) It is possible for a genetic novelty (new variation) to spread in time to all members of a population, especially if the novelty enhances the population’s chances for survival in the environment in which it exists. Thus, when a species is introduced into a new habitat, it either adapts to the change by natural selection or by some other evolutionary mechanism or else it eventually dies off. Because each new habitat means new adaptations, habitat changes have been responsible for the millions of different kinds of species and for the heterogeneity within each species. The total number of animal and plant species is estimated at between 2,000,000 and 4,500,000; authoritative estimates of the number of extinct species range from 15,000,000 up to 16,000,000,000. (3)Although the use of classification as a means of producing some kind of order out of this staggering number of different types of organisms appears as early as the book of Genesis—with references to cattle, beasts, fowl, creeping things, trees, etc.—the first scientific attempt at classification is attributed to the Greek philosopher Aristotle, who tried to establish a system that would indicate the relationship of all things to each other. He arranged everything along a scale, or “ladder of nature”, with nonliving things at the bottom; plants were placed below animals, and man was at the top. (4)Other schemes that have been used for grouping species include large anatomical similarities, such as wings or fins, which indicate a natural relationship, and also similarities in reproductive structures. (5) At the present time taxonomy is based on two major assumptions: one is that similar body construction can be used as a criterion for a classification grouping; the other is that, in addition to structural similarities, evolutionary and molecular relationships between organisms can be used as a means for determining classification.
考题
问答题Practice 2 Until recently, scientists knew little about life in the deep sea, nor had they reason to believe that it was being threatened. Now, with the benefit of technology that allows for deeper exploration, researchers have uncovered a remarkable array of species inhabiting the ocean floor at depths of more than 660 feet, or about 200 meters. At the same time, however, technology has also enabled fishermen to reach far deeper than ever before, into areas where bottom trawls can destroy in minutes what has taken nature hundreds and in some cases thousands of years to build. Many of the world's coral species, for example, are found at depths of more than 200 meters. It is also estimated that roughly half of the world's highest seamounts - areas that rise from the ocean floor and are particularly rich in marine life - are also found in the deep ocean. These deep sea ecosystems provide shelter, spawning and breeding areas for fish and other creatures, as well as protection from strong currents and predators. Moreover, they are believed to harbor some of the most extensive reservoirs of life on earth, with estimates ranging from 500,000 to 100 million species inhabiting these largely unexplored and highly fragile ecosystems.
考题
问答题Practice 1 Biological diversity, or biodiversity, means the variety of life on earth and includes the entire web of living organisms ranging from soil microbes, frogs, and trees to bears and blue whales. From the perspective of sustainable use, wildlife is a renewable resource that provides many benefits and socioeconomic advantages. Sustainable use is defined as “the use of components of biodiversity in a way and at a rate that does not lead to long term decline” but maintains the “potential to meet the needs and aspirations of present and future generations.”
考题
问答题Practice 6 Yet just as we are beginning to recognize the tremendous diversity of life in these areas, along with the potential benefits newly found species may hold for human society in the form of potential food products and new medicines, they are at risk of being lost forever. With enhanced ability both to identify where these species-rich areas are located and to trawl in deeper water than before, commercial fishing vessels are now beginning to reach down with nets the size of football fields, catching everything in their path while simultaneously crushing fragile corals and breaking up the delicate structure of reefs and seamounts that provide critical habitat to the countless species of fish and other marine life that inhabit the deep ocean floor. Because deep sea bottom trawling is a recent phenomenon, the damage that has been done is still limited. If steps are taken quickly to prevent this kind of destructive activity from occurring on the high seas, the benefits both to the marine environment and to future generations are incalculable. And they far outweigh the short-term costs to the fishing industry.
考题
问答题Despite the basic biological, chemical, and physical similarities found in all living things, a diversity of life exists not only among and between species but also within every natural population. The phenomenon of diversity has had a long history of study because so many of the variations that exist in nature are visible to the eye. 1) It has been suggested that sexual reproduction became the dominant type of reproduction among organisms because of its inherent advantage of variability, which is the mechanism that enables a species to adjust to changing conditions.New variations are potentially present in genetic differences, but how preponderant a variation becomes in a gene pool depends upon the number of offspring the mutants or variants produce (differential reproduction). 2)It is possible for a genetic novelty (new variation) to spread in time to all members of a population, especially if the novelty enhances the population’s chances for survival in the environment in which it exists.Thus, when a species is introduced into a new habitat, it either adapts to the change by natural selection or by some other evolutionary mechanism or else it eventually dies off. Because each new habitat means new adaptations, habitat changes have been responsible for the millions of different kinds of species and for the heterogeneity within each species. The total number of animal and plant species is estimated at between 2,000,000 and 4,500,000; authoritative estimates of the number of extinct species range from 15,000,000 up to 16,000,000,000. 3)Although the use of classification as a means of producing some kind of order out of this staggering number of different types of organisms appears as early as the book of Genesis—with references to cattle, beasts, fowl, creeping things, trees, etc.—the first scientific attempt at classification is attributed to the Greek philosopher Aristotle, who tried to establish a system that would indicate the relationship of all things to each other.He arranged everything along a scale, or “ladder of nature”, with nonliving things at the bottom; plants were placed below animals, and man was at the top. 4)Other schemes that have been used for grouping species include large anatomical similarities, such as wings or fins, which indicate a natural relationship, and also similarities in reproductive structures. 5)At the present time taxonomy is based on two major assumptions: one is that similar body construction can be used as a criterion for a classification grouping; the other is that, in addition to structural similarities, evolutionary and molecular relationships between organisms can be used as a means for determining classification.
考题
单选题The reference to the peppered moth in line 43 is used to ______.A
provide an example of a species that has been shown to undergo macroevolutionB
demonstrate that many species have undergone the process of microevolutionC
prove that all living things descended from a common ancestorD
question the use of the fossil record to support DarwinismE
highlight the dangers to the environment of pollution from industrial complexes
热门标签
最新试卷
