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 in-crease 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 com-binations 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 in-creased 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 counter-acting 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 obvi-ously reduces its richness. However,it is not clear how such disturbance damages the main-tenance 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?

题干意为“为什么蚂蚁被比喻为生态系统的工程师？”虽然题干中出现了细节信息词/短语ants , ecosystem engineers，但它们都是短文主题词（出现在短文标题中的名词及名词短语），因此不用它们作为定位线索。备选项中也出现了细节信息词/短语own nests, food , activity , environment , predators，利用它们作为定位线索，在短文中第一段和第二段中找到相关句：（第一段）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. （第二段）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．定位线索词分散出现在两个段落中，因此这两个段落都需要关注。第一段提到“Exeter大学所做的研究表明，蚂蚁作为‘生态系统工程师’和食肉动物的活动对当地的环境影响很大。该研究发表在《动物生态学》杂志上，这项研究发现蚂蚁对当地的环境有着两个显著的影响”。第二段第一句中也出现了定位线索词，因此也关注这个句子。该句意为“第一，通过挪动土壤筑巢或采集食物，蚂蚁影响土壤的营养水平” 结合这两个句子的意思可以得出这样的结论：蚂蚁挪动土壤筑巢或采集食物这类活动影响着土壤的营养水平，以至于最终它们对当地环境产生巨大的影响，因此蚂蚁被称为“生态系统工程师”。因此答案为C项“因为蚂蚁的活动对环境产生了影响”。
题干意为“作为食肉动物，蚂蚁……”。利用题干及备选项中的细节信息词/短语predators,small as well as large animals,nutritious food,soil,food,decomposers, species , food chain作为定位线索，在第三段中找到相关句：Secondly, they prey on a wide range of other animals（与small as well as large animals呼应）,including larger prey which can be attacked by vast numbers of ant workers．第三段是独立成段句，这样的段落常设置问题。该句提到“第二，它们捕食各种各样的动物，包括那些被大量工蚁吞吃的大猎物”。由此可知蚂蚁会捕食各种各样的动物，甚至包括体积比它们大的动物，因此答案为A项“捕食体积 小的动物也捕食体积大的动物”。
题干意为“Dirk Sanders以蚂蚁怎样……为研究中心”。利用题干及备选项中的细节信息词/短语Dirk Sanders" study, huge numbers, resources and territory, other predators , invading animals , survival , big impact on the environment作为定位线索，在第四段和第五段中找到相关句：（第四段）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. （第五段）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（与big impact on the environment呼应）,having a big influence on the grassland food web , ” Sanders said．定位线索词分散出现在第四段和第五段中，因此这两个段落都需要关注。第四段提到“Dirk Sanders是这项研究的发起人，就职于该大学的生态与保护中心，他说‘蚂蚁是高效的食肉动物，而且能大量繁殖。它们具有很强的领地意识，而且会竭尽全力对抗其他的食肉动物来保护自己的领地。所有这些都意味着蚂蚁对周围环境有很大的影响’”。接下来第五段提到“在这项研究中，我们（回指前一段中提到的包括Dirk Sanders在内的研究者们）第一次对蚂蚁带来的这种影响及微妙程度进行研究”。该句表明Dirk Sanders 以蚂蚁带来的这种影响为研究中心。“这种影响”回指上一段中提到的蚂蚁对周围环境的影响，因此该题答案为D项“（蚂蚁怎样）对环境产生如此巨大的影响”。
题干意为“第六段告诉了我们什么？”该题问及第六段的主要内容，即段落大意，因此该题属于主旨题。还是首先考虑利用备选项中的细节信息词/短语negative influ-ence,area,population, positive influence,ants" predation, higher density作为定位线索，在第六段中找到需要重点阅读的句子：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．定位线索词集中出现在第六段的第二句和第三句中，因此首先重点阅读这两个句子。这两个句子提到“研究发现，一个地区的蚂蚁密度小，而其他动物尤其是食草动物和腐生物的数量和种类会增多。如果蚂蚁的密度大，就不可能产生同样的影响，或者产生相反的影响，这表明，蚂蚁的掠食行为会抵消蚂蚁对环境带来的积极影响”。依据这两个句子可以得出这样的结论：当蚂蚁密度小（即数量少）的时候会对环境产生积极的影响，因为其他．动物尤其是食草动物和腐生物的数量和种类会增多，因此该题答案为B项“当蚂蚁的数量少的时候会对一个地区产生积极的影响”。虽然短文中提到了“蚂蚁的掠食行为会抵消蚂蚁对环境带来的积极影响”，但这是在蚂蚁的密度大的情况下出现的情况，而不是在任何情况都是如此，因此选项C不 正确。