搜题
问题详情
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 animals
B: collect nutritious food from the soil
C: collect food as decomposers
D: prey on species much higher up the food chain
未搜索到的试题可在搜索页快速提交，您可在会员中心"提交的题"快速查看答案。
收藏该题
查看答案
搜题
相关问题推荐
Do we have to wear these name tags?
A: lists
B: forms
C: codes
D: labels
A: lists
B: forms
C: codes
D: labels
共用题干
1. Do you know a child who survived leukemia（白血病）?Do you have a mother , sister or aunt whose breast cancer was found early thanks to a mammogram（乳腺X光照片）?Do you have a friend or coworker who quit smoking to reduce their risk of lung cancer? Each of these individuals benefited from the American Cancer Society's research program.
2.Each day scientists supported by the American Cancer Society work to find breakthroughs that will take US one step closer to a cure.The American Cancer Society has long recognized that research holds the ultimate answers to the prevention,diagnosis and treatment of cancer.
3.As the largest source of nonprofit cancer research funds in the United States,the American Cancer Society devotes over $100 million each year to research.Since 1946,they've invested more than $2. 4 billion in research. The investment has paid rich dividends（回报、效益）.In 1946,only one in four cancer patients was alive five years after diagnosis;today 60 percent live longer than five years.
4.Investigators and health professionals in universities,research institutes and hospitals throughout the country receive grants from the American Cancer Society.Of the more than 1,300 new applications received each year,only 11 percent can be funded.If the American Cancer Society had more money available for research funding,nearly 200 more applications considered outstanding could be funded each year.
5.You can help fund more of these applications by participating in the American Cancer Society Relay（接力）for Life,a team event to fight cancer. More funding means more cancer breakthroughs and more lives being saved.To learn more,call Donna Hood,chair with the Neosho Relay for Life of the American Cancer Society at 451-4880.
The American Cancer Society's research program has benefited________.
A:lack of funding
B:many cancer patients
C:more lives being saved
D:more than five years
E:the ultimate answers
F: more funding
1. Do you know a child who survived leukemia（白血病）?Do you have a mother , sister or aunt whose breast cancer was found early thanks to a mammogram（乳腺X光照片）?Do you have a friend or coworker who quit smoking to reduce their risk of lung cancer? Each of these individuals benefited from the American Cancer Society's research program.
2.Each day scientists supported by the American Cancer Society work to find breakthroughs that will take US one step closer to a cure.The American Cancer Society has long recognized that research holds the ultimate answers to the prevention,diagnosis and treatment of cancer.
3.As the largest source of nonprofit cancer research funds in the United States,the American Cancer Society devotes over $100 million each year to research.Since 1946,they've invested more than $2. 4 billion in research. The investment has paid rich dividends（回报、效益）.In 1946,only one in four cancer patients was alive five years after diagnosis;today 60 percent live longer than five years.
4.Investigators and health professionals in universities,research institutes and hospitals throughout the country receive grants from the American Cancer Society.Of the more than 1,300 new applications received each year,only 11 percent can be funded.If the American Cancer Society had more money available for research funding,nearly 200 more applications considered outstanding could be funded each year.
5.You can help fund more of these applications by participating in the American Cancer Society Relay（接力）for Life,a team event to fight cancer. More funding means more cancer breakthroughs and more lives being saved.To learn more,call Donna Hood,chair with the Neosho Relay for Life of the American Cancer Society at 451-4880.
The American Cancer Society's research program has benefited________.
A:lack of funding
B:many cancer patients
C:more lives being saved
D:more than five years
E:the ultimate answers
F: more funding
共用题干
Trying to Find a Partner
One of the most striking findings of a recent poii in the UK is that of the people interviewed, one in two believes that it is becoming more difficult to meet someone to start a family with.
Why are many finding it increasingly difficult to start and sustain intimate relationships?
Does modern life really make it harder to , fall in love?Or are we making it harder for ourselves?
It is certainly the case today that contemporary couples benefit in different ways from relationships.Women no longer rely upon partners for economic security or status.A man doesn't expect his spouse to be in sole charge of running his household and raising his children.
But perhaps the knowledge that we can live perfectly well without a partnership means that it takes much more to persuade people to abandon their independence.
In theory,finding a partner should be much simpler these days.Only a few generations ago, your choice of soulmate（心上人）was constrained by geography , social convention and family tradition .Although it was never explicit,many marriages were essentially arranged.
Now those barriers have been broken down.You can approach a builder or a brain surgeon in any bar in any city on any given evening. When the world is your oyster（牡砺）,you surely have a better chance of finding a pearl.
But it seems that the old conventions have been replaced by an even tighter constraint:the tyranny of choice.
The expectations of partners are inflated to an unmanageable degree:good looks,impressive salary,kind to grandmother,and right socks.There is no room for error in the first impression.
We think that a relationship can be perfect. If it isn't,it is disposable.We work to protect ourselves against future heartache and don't put in the hard emotional labor needed to build a strong relationship.Of course,this is complicated by realities.The cost of housing and child-rearing creates pressure to have a stable income and career before a life partnership.
What does the recent poil show?
A: It is getting more difficult for a woman to find her husband.
B: It is getting increasingly difficult to start a family.
C: It is getting more difficult for a man to find his wife.
D: It is getting increasingly difficult to develop an intimate relationship with your spouse.
Trying to Find a Partner
One of the most striking findings of a recent poii in the UK is that of the people interviewed, one in two believes that it is becoming more difficult to meet someone to start a family with.
Why are many finding it increasingly difficult to start and sustain intimate relationships?
Does modern life really make it harder to , fall in love?Or are we making it harder for ourselves?
It is certainly the case today that contemporary couples benefit in different ways from relationships.Women no longer rely upon partners for economic security or status.A man doesn't expect his spouse to be in sole charge of running his household and raising his children.
But perhaps the knowledge that we can live perfectly well without a partnership means that it takes much more to persuade people to abandon their independence.
In theory,finding a partner should be much simpler these days.Only a few generations ago, your choice of soulmate（心上人）was constrained by geography , social convention and family tradition .Although it was never explicit,many marriages were essentially arranged.
Now those barriers have been broken down.You can approach a builder or a brain surgeon in any bar in any city on any given evening. When the world is your oyster（牡砺）,you surely have a better chance of finding a pearl.
But it seems that the old conventions have been replaced by an even tighter constraint:the tyranny of choice.
The expectations of partners are inflated to an unmanageable degree:good looks,impressive salary,kind to grandmother,and right socks.There is no room for error in the first impression.
We think that a relationship can be perfect. If it isn't,it is disposable.We work to protect ourselves against future heartache and don't put in the hard emotional labor needed to build a strong relationship.Of course,this is complicated by realities.The cost of housing and child-rearing creates pressure to have a stable income and career before a life partnership.
What does the recent poil show?
A: It is getting more difficult for a woman to find her husband.
B: It is getting increasingly difficult to start a family.
C: It is getting more difficult for a man to find his wife.
D: It is getting increasingly difficult to develop an intimate relationship with your spouse.
共用题干
Most of us walk and carry items in our hands every day.These are seemingly simple activities that the majority of us don't question.But an international team of researchers,including Dr. Richmond from GW's Columbian College of Arts and Sciences,have discovered that human walking upright, may have originated millions of years ago as an adaptation to carrying scarce（稀有的）,high-quality resources.The team of researchers from the U.S.,England,Japan and Portugal investigated the behavior of modern-day chimpanzees（黑猩猩）as they competed for food resources,in an effort to understand what ecological settings would lead a large ape（类人猿）一one that resembles the 6 million-year old ancestor we shared in common with living chimpanzees一to walk on two legs.
"These chimpanzees provide a model of the ecological conditions under which our earliest ancestors might have begun walking on two legs",said Dr. Richmond.
The research findings suggest that chimpanzees switch to moving on two limbs instead of four in situations where they need to monopolize a resource.Standing on two legs allows them to carry much more at one time because it frees up their hands. Over time , intense bursts of bipedal（二足的）activity may have led to anatomical（解剖学的）changes that in turn became the subject of natural selection where competition for food or other resources was strong.
Two studies were conducted by the team in Guinea. The first study was conducted by the team in Kyoto University's "outdoor laboratory" in a natural clearing in Bossou Forest. Researchers allowed the wild chimpanzees access to different combinations of two different types of nut一the oil palm nut,which is naturally widely available,and the coula nut,which is not.The chimpanzees' behavior was monitored in three situations:(a)when only oil palm nuts were available,(b)when a small number of coula nuts were available,and(c)when coula nuts were the majority available resource.
When the rare coula nuts were available only in small numbers,the chimpanzees transported more at one time.Similarly,when coula nuts were the majority resource,the chimpanzees ignored the oil palm nuts altogether. The chimpanzees regarded the coula nuts as a more highly-prized resource and competed for them more intensely.
In such high-competition settings,the frequency of cases in which the chimpanzees started moving on two legs increased by a factor of four. Not only was it obvious that bipedal movement allowed them to carry more of this precious resource,but also that they were actively trying to move as much as they could in one go by using everything available一even their mouths.
The second study,by Kimberley Hockings of Oxford Brookes University,was a 14-month study of Bossou chimpanzees crop-raiding,a situation in which they have to compete for rare and unpredictable resources.Here,35 percent of the chimpanzees activity involved some sort of bipedal movement,and once again,this behavior appeared to be linked to a clear attempt to carry as much as possible at one time.
The chimpanzees competed for the coula nuts more intensely.
A:Right
B:Wrong
C:Not mentioned
Most of us walk and carry items in our hands every day.These are seemingly simple activities that the majority of us don't question.But an international team of researchers,including Dr. Richmond from GW's Columbian College of Arts and Sciences,have discovered that human walking upright, may have originated millions of years ago as an adaptation to carrying scarce（稀有的）,high-quality resources.The team of researchers from the U.S.,England,Japan and Portugal investigated the behavior of modern-day chimpanzees（黑猩猩）as they competed for food resources,in an effort to understand what ecological settings would lead a large ape（类人猿）一one that resembles the 6 million-year old ancestor we shared in common with living chimpanzees一to walk on two legs.
"These chimpanzees provide a model of the ecological conditions under which our earliest ancestors might have begun walking on two legs",said Dr. Richmond.
The research findings suggest that chimpanzees switch to moving on two limbs instead of four in situations where they need to monopolize a resource.Standing on two legs allows them to carry much more at one time because it frees up their hands. Over time , intense bursts of bipedal（二足的）activity may have led to anatomical（解剖学的）changes that in turn became the subject of natural selection where competition for food or other resources was strong.
Two studies were conducted by the team in Guinea. The first study was conducted by the team in Kyoto University's "outdoor laboratory" in a natural clearing in Bossou Forest. Researchers allowed the wild chimpanzees access to different combinations of two different types of nut一the oil palm nut,which is naturally widely available,and the coula nut,which is not.The chimpanzees' behavior was monitored in three situations:(a)when only oil palm nuts were available,(b)when a small number of coula nuts were available,and(c)when coula nuts were the majority available resource.
When the rare coula nuts were available only in small numbers,the chimpanzees transported more at one time.Similarly,when coula nuts were the majority resource,the chimpanzees ignored the oil palm nuts altogether. The chimpanzees regarded the coula nuts as a more highly-prized resource and competed for them more intensely.
In such high-competition settings,the frequency of cases in which the chimpanzees started moving on two legs increased by a factor of four. Not only was it obvious that bipedal movement allowed them to carry more of this precious resource,but also that they were actively trying to move as much as they could in one go by using everything available一even their mouths.
The second study,by Kimberley Hockings of Oxford Brookes University,was a 14-month study of Bossou chimpanzees crop-raiding,a situation in which they have to compete for rare and unpredictable resources.Here,35 percent of the chimpanzees activity involved some sort of bipedal movement,and once again,this behavior appeared to be linked to a clear attempt to carry as much as possible at one time.
The chimpanzees competed for the coula nuts more intensely.
A:Right
B:Wrong
C:Not mentioned
共用题干
Exercise
Whether or not exercise adds___1___the length of life,it is common experience that a certain___2___of regular exercise improves the health and contributes a feeling of wellbeing.
Furthermore,exercise___3___involves play and recreation,and relieves nervous tension and mental fatigue in so doing,is not only pleasant but beneficial. How much and what kind of exercise one should___4___merits careful consideration. The growing child and the normal young man and young woman thrill with the exhilaration of strenuous sports.They fatigue to the___5___of exhaustion but recover promptly with a period of rest. But not so with___6___of middle age and beyond. For them moderation is___7___vital importance. Just how much exercise a person of a given age can safely take is a question___8___to answer. Individual variability is___9___ great to permit of generalization.
A game of tennis may be perfectly safe for one person of forty but folly for another. The safe limit for exercise___10___ on the condition of the heart,the condition of the muscles,the type of exercise,and the regularity with which it is taken.Two general suggestions,however,will___11___ as sound advice for anyone.The first is that the condition of the heart and general health should be___12___ periodically by careful, thorough physical examinations. The___13___is that exercise should be kept below the point of physical exhaustion.
What type of exercise one should___14___depends upon one's physical condition. Young people can safely enjoy vigorous competitive sports,but most older persons do better to limit themselves to less strenuous activities. Walking,swimming,skating are among the sports that one can enjoy and safely participate___15___throughout life. Regularity is important if one is to get the most enjoyment and benefit out of exercise.
15._________
A: with
B: from
C: in
D: on
Exercise
Whether or not exercise adds___1___the length of life,it is common experience that a certain___2___of regular exercise improves the health and contributes a feeling of wellbeing.
Furthermore,exercise___3___involves play and recreation,and relieves nervous tension and mental fatigue in so doing,is not only pleasant but beneficial. How much and what kind of exercise one should___4___merits careful consideration. The growing child and the normal young man and young woman thrill with the exhilaration of strenuous sports.They fatigue to the___5___of exhaustion but recover promptly with a period of rest. But not so with___6___of middle age and beyond. For them moderation is___7___vital importance. Just how much exercise a person of a given age can safely take is a question___8___to answer. Individual variability is___9___ great to permit of generalization.
A game of tennis may be perfectly safe for one person of forty but folly for another. The safe limit for exercise___10___ on the condition of the heart,the condition of the muscles,the type of exercise,and the regularity with which it is taken.Two general suggestions,however,will___11___ as sound advice for anyone.The first is that the condition of the heart and general health should be___12___ periodically by careful, thorough physical examinations. The___13___is that exercise should be kept below the point of physical exhaustion.
What type of exercise one should___14___depends upon one's physical condition. Young people can safely enjoy vigorous competitive sports,but most older persons do better to limit themselves to less strenuous activities. Walking,swimming,skating are among the sports that one can enjoy and safely participate___15___throughout life. Regularity is important if one is to get the most enjoyment and benefit out of exercise.
15._________
A: with
B: from
C: in
D: on
