1、2014-03-16 01 Costs and Benefits of Social LifeMany think that the reason so many animals live with others of their species is that socialcreatures are higher up the evolutionary scale and so are better adapted and leave moreoffspring than do animals that live solitary lives. However, in each and ev
2、ery species, generationafter generation, relatively social and relatively solitary types compete unconsciously with oneanother in ways that determine who leaves more offspring on average. In some species, the moresocial individuals have won out, but in a large majority, it is the solitary types that
3、 haveconsistently left more surviving descendants on average.Paragraph 2But how can living alone ever be superior to living together? Under some conditions,a cost-benefit comparison favors solitary life over a more social existence. For example, amongmost social species, animals have to expend time
4、and energy competing for social status. Thosethat do not occupy the top positions regularly have to signal their submissive state to theirsuperiors if they are to be permitted to remain in the group. This can take up a major share of asocial subordinates life. In fact, even in small social groups th
5、ere are both subtle competition andnot-so-subtle competition.1 . Which of the following can be inferred from paragraph 2 as a reason for saying that undersome conditions a solitary life is superior to a more social life? Solitary animals can compete more successfully against animals of other species
6、 than socialanimals can. Solitary animals can hide from predators more easily than groups of animals can. Solitary animals do not need to spend time and energy competing for social status. Solitary animals do not need large quantities of food to survive.细节题：找到定位局，其下一句是：Among most social species, ani
7、mals have to expend time and energycompeting for social status.和C是同义替换。Paragraph 3Social groups also offer opportunities for reproductive interference. Breeding malesthat live in close association with more attractive rivals may lose their mates to these individuals.In addition, sociality has two ot
8、her potential disadvantages. The first is heightened competitionfor food, which occurs in animals as different as colonial fieldfares (a kind of songbird) and groupsof lions, whose females are often pushed from their food by hungry males. The second isincreased vulnerability to parasites and disease
9、, which plague social species of all sorts. While itis true that some social animals have evolved special responses designed to combat parasites anddisease, those responses can only reduce, but cannot totally eliminate, the damage caused bythose threats, and the responses may even carry their own co
10、sts. Thus, honeybees warm theirhives in response to an infestation by a fungal pathogen, which apparently helps kill theheat-sensitive fungus, but at the price of time and energy expended by the heat-producingworkers.2 . The word “potential“ in the passage is closest in meaning to possible serious c
11、ommon related单词题：潜在地选A3 . Which of the following is associated in paragraph 3 with reproductive interference in socialanimals Females being pushed away from their food by hungry males Breeding males losing their mates to more attractive males Parasites and disease infecting the eggs of breeding fema
12、les Females warming their habitats to care a fungal pathogen细节题：定位到第一句，然后看下一句：Breeding males that live in close association with more attractiverivals may lose their mates to these individuals.这句话的主干是breeding males lose their mates.直接与B是对应的。4 . According to paragraph 3 which of the following is like
13、ly to increase when animals live withother members of their species rather than alone reproductive success unpredictable behavior among males resistance to disease competition for food细节题：回到文中可以看到主要内容是：sociality has two other potential disadvantages. The first isheightened competition for food；The s
14、econd is increased vulnerability to parasites and disease,which plague social species of all sorts.回到选项只有D是对的5 . In paragraph 3 why does author discuss “honeybees warming their hives in response to aninfestation by a fungal pathogen“? To give an example of how living in groups benefits animals To il
15、lustrate how social species combat parasites and disease To indicate that worker bees are the most active in fighting parasites and disease To demonstrate that avoiding a disadvantage of social living can carry its own costs修辞目的题：上一句为：While it is true that some social animals have evolved special re
16、sponses designed tocombat parasites and disease, those responses can only reduce, but cannot totally eliminate, thedamage caused by those threats, and the responses may even carry their own costs.说的是他们有自己的responses，目的是combat parasites and disease，但是也会carry their owncosts.和D说的是相符的。Paragraph 4If socia
17、l living carries a heightened risk of infection, then the larger the group, thegreater the risk. This prediction holds for cliff swallows, which pack their nests side by side incolonies composed of anywhere from a handful of birds to several thousand pairs. The moreswallows nesting together, the gre
18、ater the chance that at least one bird will be infested withswallow bugs, which can then readily spread from one nest to another.Paragraph 5The parasites and fungi that make life miserable for swallows and other socialcreatures demonstrate that if sociality is to evolve, the assorted costs of living
19、 together must beoutweighed by compensatory benefits. Cliff swallows may join others to take advantage of theimproved foraging that comes from following companions to good feeding sites, while otheranimals, such as male imperial penguins, save thermal energy by huddling shoulder to shoulderduring th
20、e brutal Antarctica winter. Still others, such as lionesses, join forces to fend off enemiesof their own species.6 . The word “heightened“ in the passage is closest in meaning to long-term increased real unnecessary单词题：增高增强选B7 . Paragraphs 4 and 5 support all of the following statements about cliff
21、swallows EXCEPT They feed primarily on bugs found in their nests. They sometimes live in groups of only a few birds. They sometimes locate good feeding sites by following other cliff swallows. They build their nests close to the nests of other cliff swallows.排除题：到选项中找错误选项特征的。回到文中，可以看到handful of bird
22、s和which can then readily spreadfrom one nest to another.以及to good feeding sites分别对应选项BCD因此选A8 . The word “assorted“ in the passage is closest in meaning to usual obvious various severe单词题：各式各样的选C9 . Which of the following is NOT identified in paragraph 5 as a need that some animals canbetter satisfy
23、 when they live with other members of their species? The need to find food The need to locate breeding sits The need to preserve body heat The need to protect themselves from attackers排除题：看选项可以看到每个选项分别是find；locate；preserve heat；protect from attackers回到文中看到foraging=find；save thermal energy=preserve h
24、eat；fend off enemie=protect fromattackerss对应ACD因袭选BParagraph 6The most widespread fitness benefit for social animals, however, probably isimproved protection against predators. Many studies have shown that animals in groups gain byreducing the individual risk of being captured, or by spotting danger
25、 sooner, or by attacking theirenemies in groups. Males in nesting colonies of bluegill sunfish cooperate in driving egg-eatingbullhead catfish away from their nests at the bottom of a freshwater lake. While bluegills haveadopted social behavior to avoid predation, closely related species that nest a
26、lone have evolvedmeans to protect themselves while nesting alone. Thus, the solitary pumpkinseed sunfish, amember of the same genus as the bluegill, has powerful biting jaws and so can repel egg-eatingenemies on its own, whereas bluegills have small, delicate mouths good only for inhaling small,soft
27、-bodied insect larvae. Pumpkinseed sunfish are in no way inferior to or less well adapted thanbluegills because they are solitary; they simply gain less through social living, which makessolitary nesting the adaptive tactic for them.、1 0 . In paragraph 6 , why does the author compare the bluegill su
28、nfish to the pumpkinseedsunfish? To show that nesting has different costs and benefits for solitary organisms than it has fororganisms living with other members of the same species To provide evidence that social nesting is usually superior to solitary nesting To argue that, in closely related speci
29、es, the feeding organs of solitary organisms usuallydiffer from those of social organisms To show that closely related species can be social or solitary depending on which behaviorbetter enables them to fight off predators修辞目的题：回到文中看不到明显的定位句，但是发现前半段是说bluegill sunfish后半段再说pumpkinseedsunfish。所以看整段首位句。
30、The most widespread fitness benefit for social animals, however,probably is improved protection against predators. Many studies have shown that animals in groupsgain by reducing the individual risk of being captured, or by spotting danger sooner, or by attackingtheir enemies in groups.可以看到主要是说动物保护自己
31、防御敌人，又看到文中明显有manystudies have shown。因此选项AD最符合。但是A说的是动物消耗与收益D是说动物抵抗外敌。因此选D1 1 . The word “tactic” in the passage is closet in meaning to strategy development result characteristic单词题：策略选AParagraph 3Social groups also offer opportunities for reproductive interference. Breeding males that live inclose
32、association with more attractive rivals may lose their mates to these individuals. In addition,sociality has two other potential disadvantages. The first is heightened competition for food,which occurs in animals as different as colonial fieldfares (a kind of songbird) and groups of lions,whose fema
33、les are often pushed from their food by hungry males.The second is increasedvulnerability to parasites and disease, which plague social species of all sorts.While it is truethat some social animals have evolved special responses designed to combat parasites anddisease, those responses can only reduc
34、e, but cannot totally eliminate, the damage caused bythose threats, and the responses may even carry their own costs.Thus, honeybees warm theirhives in response to an infestation by a fungal pathogen, which apparently helps kill theheat-sensitive fungus, but at the price of time and energy expended
35、by the heat-producingworkers.1 2 . Look at the four squares that indicate where the following sentence could be added tothe passage.Likewise, termites can reduce their risk of some infectious diseases by associating withother termites, but only at the expense of decreased physiological functioning.W
36、here would the sentence best fit? Click on a square to add the sentence to thePassage.插入题;Likewise，就说明插入的内容一定和前面说的是并列关系。该句的主要说termites can reduce theirriskby associating with other termites。A选项是The second和上一句的The first对应，所以排除B：选项前面的句子明显和插入句不并列C：选项前面的句子明显和插入句不并列D：选项前面说的是honeybees后面正好可以接termites，是很好的并
37、列关系因此选D1 3 . Directions: An introductory sentence for a brief summary of the passage is provided below.Complete the summary by selecting the THREE answer choices that express the mostimportant ideas in the passage. Some answer choices do not belong in the summary becausethey express ideas that are n
38、ot presented in the passage or are minor ideas in the passage.This question is worth 2 points.Drag your choices to the spaces where they belong. To review the passage, click on View Text.There are costs and benefits associated with living in groups.Answer choicesSolitary animals are sometimes though
39、t to bethe evolutionary scale because theyleave more surviving descendants on averagethan social animals do.（文中第一句是这句话，但是原文后面是however，也就是否定这句话。所以是错的）Social animals have evolved fewer mechanismsfor reducing the costs of competing for socialstatus than they have for reducing the risks ofexposure to di
40、sease and parasites.（不存在这种比较关系）The need for protection from predators makesanimals adopt social living, but animals thathave the ability to individually fight offpredators benefit more from solitary living.Social living has advantages such as making itpossible for animals to become more successfulat
41、 locating food, but it also has risks such asincreased competition for mates.The numerous disadvantages of living togetherlead animals to adopt social living only whenthe benefits are greater than the costs.Animals that live alone such as pumpkinseedfish need to evolve a special mouth or someother special organ to help them combatpredators. (细节不选）选3 4 5
