2018年9月2日托福阅读真题分析

　　综合点评：

　　本次考试难度中等，与TPO相似度甚高，主要考察了生物学及历史学。对于三篇文章都应该进行文章分析并整理出文章脉络之后再做题，词汇题尽量控制在2分钟左右完成，这样会留更充裕的时间给比较耗时的排除题和相对较难的推断题。

　　Passage one

　　学科分类：生物学

　　题目：Differences of Biodiversity in geographical patterns

　　内容回忆：整篇文章结构属于问题解释+比较对比型;而且最后一题出现了很久没有考过的七选五，分别选出热带和温带生物多样性的不同特点。配了两张图。

　　首段：赤道地区和温带地区物种的多样性是不同的，热带地区物种多样性要比温带好很多，然后举了很多物种的例子;

　　第二段：有很多理论提出来解释这个现象。第一个理论是：热带地区接受的光照和降水要比温带地区多很多，意味着reproduce material 也要多很多，有助于植物的reproduce， reproductive的速度也好高很多，有利于多种生物的生存，但是温带地区就要少很多。举了很多例子。

　　第三段：第二个理论是：热带地区气候比较稳定;有利于多种多样动植物的进化和发展在一个比较持续稳定的环境中进行，没有干扰和中断;但是温带地区气候季节变化比较大，很多生物要存活下来要能够忍受极端的寒冷，还举了间冰期的例子。所以物种的存活和进化需要很长的时间。

　　第四段：热带地区比温带地区持续的区间范围大。热带地区是沿着赤道向南北延伸，是一个整块的连续的地理范围，但是温带地区是分别分散在北半球和南半球的。同时因为热带地区温度较高，所以parasite 比较多，这样就不利于同一种单一植物大范围的生长，扩大了同种植物的地理间隔;而温带地区因为冬季会杀死一部分植物，所以很多植物是单一物种集中生长的。

　　第五段：热带地区任何一个canopy都可能是一个community, 环境适合多种生物生长，但是温带地区则不然。

　　参考阅读：Geographic Isolation of Species

　　Biologist Ernst Mayr defined a species as "an actually or potentially interbreeding population that does not interbreed with other such populations when there is opportunity to do so. A key event in the origin of many species is the separation of a population with its gene pool (all of the genes in a population at any one time) from other populations of the same species, thereby preventing population interbreeding. With its gene pool isolated, a separate population can follow its own evolutionary course. In the formation of many species, the initial isolation of a population seems to have been a geographic barrier. This mode of evolving new species is called allopatric speciation.

　　Many factors can isolate a population geographically. A mountain range may emerge and gradually split a population of organisms that can inhabit only lowland lakes; certain fish populations might become isolated in this way. Similarly, a creeping glacier may gradually divide a population, or a land bridge such as the Isthmus of Panama may form and separate the marine life in the ocean waters on either side.

　　How formidable must a geographic barrier be to keep populations apart? It depends on the ability of the organisms to move across barriers. Birds and coyotes can easily cross mountains and rivers. The passage of wind-blown tree pollen is also not hindered by such barriers, and the seeds of many plants may be carried back and forth on animals. In contrast, small rodents may find a deep canyon or a wide river an effective barrier. For example, the Grand Canyon, in the southwestern United States, separates the range of the white-tailed antelope squirrel from that of the closely related Harris' antelope squirrel. Smaller, with a shorter tail that is white underneath, the white-tailed antelope squirrel inhabits deserts north of the canyon and west of the Colorado River in southern California. Harris' antelope squirrel has a more limited range in deserts south of the Grand Canyon.

　　Geographic isolation creates opportunities for new species to develop, but it does not necessarily lead to new species because speciation occurs only when the gene pool undergoes enough changes to establish reproductive barriers between the isolated population and its parent population. The likelihood of allopatric speciation increases when a population is small as well as isolated, making it more likely than a large population to have its gene pool changed substantially. For example, in less than two million years, small populations of stray animals and plants from the South American mainland that managed to colonize the Galapagos Islands gave rise to all the species that now inhabit the islands.

　　When oceanic islands are far enough apart to permit populations to evolve in isolation, but close enough to allow occasional dispersions to occur, they are effectively outdoor laboratories of evolution. The Galapagos island chain is one of the world's greatest showcases of evolution. Each island was born from underwater volcanoes and was gradually covered by organisms derived from strays that rode the ocean currents and winds from other islands and continents. Organisms can also be carried to islands by other organisms, such as sea birds that travel long distances with seeds clinging to their feathers.

　　The species on the Galapagos Islands today, most of which occur nowhere else, descended from organisms that floated, flew, or were blown over the sea from the South American mainland. For instance, the Galapagos island chain has a total of thirteen species of closely related birds called Galapagos finches. These birds have many similarities but differ in their feeding habits and their beak type, which is correlated with what they eat. Accumulated evidence indicates that all thirteen finch species evolved from a single small population of ancestral birds that colonized one of the islands. Completely isolated on the island after migrating from the mainland, the founder population may have undergone significant changes in its gene pool and become a new species. Later, a few individuals of this new species may have been blown by storms to a neighboring island. Isolated on this second island, the second founder population could have evolved into a second new species, which could later recolonize the island from which its founding population emigrated. Today each Galapagos island has multiple species of finches, with as many as ten on some islands.

　　Passage two

　　学科分类：生物学

　　题目：Animal communication

　　内容回忆：整篇文章属于分类讨论，就是讨论动物交流的不同类型

　　首段：动物交流会泄漏自己的位置给predator,但是也会有很多好处：比如蜜蜂会跳舞来交流food location (第一题是个句子简化题);可以帮助提高蜂巢里其他蜜蜂的存活率，也提高蜂后的生育率。

　　第二段：动物的交流不止局限于同类物种之间，有时候prey-predator之间也会有交流，比如gazelle会使用一种叫做stout 的动作(两个蹄子立起来)来告诉捕食的lion，它们已经察觉到lion了，所以这次捕猎lion很可能会失败，这样属于对于双方都有利的交流。但是有时候这种交流是有害的，比如海豚会利用声波探知它要捕食鱼群位置。

　　第三段：一般认为动物之间的这种交流是要有一个sender 和一个receiver才能成立，但是有时候可能出现声音交流被两者意外的动物听到的情况，比如bats 利用frogs求偶的声音来捕食猎物，这种情况还会有进一步的进化，比如猴子用一种自己物种能听到但是farmer听不到的声音来warn each other在它们偷庄稼的时候。

　　第四段：现实的情况可能比之前的更复杂，动物们之间会有honest signal 和dishonest signal 两种情况。比如孔雀开屏就准确的反映了雄孔雀的健康状况，因为没有多余的营养用于伪装，虽然这种开屏也会可能引致捕食者。

　　第五段：dishonest signal 的情况：一般认为蟾蜍的声音和它们的体型是有关系的，声音越低体型越大，实力越强。但是有一种特殊的蟾蜍会在争夺领地的过程中故意发出比自己实际体型相配更低的声音，让竞争者误以为遇到了很强劲的对手;另外一种情况是深海里一种鱼会伪装成另一种会发光的鱼的雄性，然后利用发光吸引雌性然后把它吃掉。

　　参考阅读：Begging by Nestlings

　　Many signals that animals make seem to impose on the signalers costs that are overly damaging. A classic example is noisy begging by nestling songbirds when a parent returns to the nest with food. These loud cheeps and peeps might give the location of the nest away to a listening hawk or raccoon, resulting in the death of the defenseless nestlings. In fact, when tapes of begging tree swallows were played at an artificial swallow nest containing an egg, the egg in that “noisy” nest was taken or destroyed by predators before the egg in a nearby quiet nest in 29 of 37 trials.

　　Further evidence for the costs of begging comes from a study of differences in the begging calls of warbler species that nest on the ground versus those that nest in the relative safety of trees. The young of ground-nesting warblers produce begging cheeps of higher frequencies than do their tree-nesting relatives. These higher-frequency sounds do not travel as far, and so may better conceal the individuals producing them, who are especially vulnerable to predators in their ground nests. David Haskell created artificial nests with clay eggs and placed them on the ground beside a tape recorder that played the begging calls of either tree-nesting or of ground-nesting warblers. The eggs “advertised” by the tree-nesters' begging calls were found bitten significantly more often than the eggs associated with the ground-nesters' calls.

　　The hypothesis that begging calls have evolved properties that reduce their potential for attracting predators yields a prediction: baby birds of species that experience high rates of nest predation should produce softer begging signals of higher frequency than nestlings of other species less often victimized by nest predators. This prediction was supported by data collected in one survey of 24 species from an Arizona forest, more evidence that predator pressure favors the evolution of begging calls that are hard to detect and pinpoint.

　　Given that predators can make it costly to beg for food, what benefit do begging nestlings derive from their communications? One possibility is that a noisy baby bird provides accurate signals of its real hunger and good health, making it worthwhile for the listening parent to give it food in a nest where several other offspring are usually available to be fed. If this hypothesis is true, then it follows that nestlings should adjust the intensity of their signals in relation to the signals produced by their nestmates, who are competing for parental attention. When experimentally deprived baby robins are placed in a nest with normally fed siblings, the hungry nestlings beg more loudly than usual—but so do their better-fed siblings, though not as loudly as the hungrier birds.

　　If parent birds use begging intensity to direct food to healthy offspring capable of vigorous begging, then parents should make food delivery decisions on the basis of their offsprings’ calls. Indeed, if you take baby tree swallows out of a nest for an hour feeding half the set and starving the other half, when the birds are replaced in the nest, the starved youngsters beg more loudly than the fed birds, and the parent birds feed the active beggars more than those who beg less vigorously.

　　As these experiments show, begging apparently provides a signal of need that parents use to make judgments about which offspring can benefit most from a feeding. But the question arises, why don't nestlings beg loudly when they aren't all that hungry? By doing so, they could possibly secure more food, which should result in more rapid growth or larger size, either of which is advantageous. The answer lies apparently not in the increased energy costs of exaggerated begging—such energy costs are small relative to the potential gain in calories—but rather in the damage that any successful cheater would do to its siblings, which share genes with one another. An individual's success in propagating his or her genes can be affected by more than just his or her own personal reproductive success. Because close relatives have many of the same genes, animals that harm their close relatives may in effect be destroying some of their own genes. Therefore, a begging nestling that secures food at the expense of its siblings might actually leave behind fewer copies of its genes overall than it might otherwise.

　　Passage three

　　学科分类：历史学

　　题目：Eli Terry’s clocks

　　内容回忆：以时间顺序介绍 Eli Terry革新表的历史历程

　　第一段：钟表一开始属于luxury 的物品，不是普通人可以有的，然后大段介绍钟表手工制作的过程，非常精细(考了否定事实信息题)。一年估计一个师傅只能制作12-20个钟。

　　第二段：Eli Terry 受到德国制造业的启发，革新了过程，使用木头而不是金属来制作零件，提高了制作效率，钟表的精确度虽然下降，但是也使价格下降到了一个大家都可以接受的范围。然后他受到军事思想的启发使用了流水化作业，建造了water-powered的工厂，提高了整体制作的数量，使得中产阶级也能享受由钟表带来的社会地位。

　　第三段：虽然革新，但是还是运输不便，不能使大家都享受，很多人买了表之后要自己额外定做一个外壳。然后1816年进一步革新，使得钟表的受众范围进一步扩大，peddlers也能够售卖。Eli Terry 还为此申请了一个专利，但是专利受到了大量仿制和侵权。

　　第五段： Terry 为了应对侵权，要进一步改革表，他和一个来自其他机构的人一起革新制作了一种新的表。然后是新表的工艺。原先的木质框架用玻璃取代。虽然在工艺制造上的独创性并没有得到肯定，但是它引领了钟表的时尚潮流，确立了一种新的风潮。

　　参考阅读：The Invention of the Mechanical Clock

　　In Europe, before the introduction of the mechanical clock, people told time by sun (using, for example, shadow sticks or sun dials) and water clocks. Sun clocks worked, of course, only on clear days; water clocks misbehaved when the temperature fell toward freezing, to say nothing of long-run drift as the result of sedimentation and clogging. Both these devices worked well in sunny climates; but in northern Europe the sun may be hidden by clouds for weeks at a time, while temperatures vary not only seasonally but from day to night.

　　Medieval Europe gave new importance to reliable time. The Catholic Church had its seven daily prayers, one of which was at night, requiring an alarm arrangement to waken monks before dawn. And then the new cities and towns, squeezed by their walls, had to know and order time in order to organize collective activity and ration space. They set a time to go to work, to open the market, to close the market, to leave work, and finally a time to put out fires and go to sleep. All this was compatible with older devices so long as there was only one authoritative timekeeper; but with urban growth and the multiplication of time signals, discrepancy brought discord and strife. Society needed a more dependable instrument of time measurement and found it in the mechanical clock.

　　We do not know who invented this machine, or where. It seems to have appeared in Italy and England (perhaps simultaneous invention) between 1275 and 1300. Once known, it spread rapidly, driving out water clocks but not solar dials, which were needed to check the new machines against the timekeeper of last resort. These early versions were rudimentary, inaccurate, and prone to breakdown.

　　Ironically, the new machine tended to undermine Catholic Church authority. Although church ritual had sustained an interest in timekeeping throughout the centuries of urban collapse that followed the fall of Rome, church time was nature`s time. Day and night were divided into the same number of parts, so that except at the equinoxes, day and night hours were unequal; and then of course the length of these hours varied with the seasons. But the mechanical clock kept equal hours, and this implied a new time reckoning. The Catholic Church resisted, not coming over to the new hours for about a century. From the start, however, the towns and cities took equal hours as their standard, and the public clocks installed in town halls and market squares became the very symbol of a new, secular municipal authority. Every town wanted one; conquerors seized them as especially precious spoils of war; tourists came to see and hear these machines the way they made pilgrimages to sacred relics.

　　The clock was the greatest achievement of medieval mechanical ingenuity. Its general accuracy could be checked against easily observed phenomena, like the rising and setting of the sun. The result was relentless pressure to improve technique and design. At every stage, clockmakers led the way to accuracy and precision; they became masters of miniaturization, detectors and correctors of error, searchers for new and better. They were thus the pioneers of mechanical engineering and served as examples and teachers to other branches of engineering.

　　The clock brought order and control, both collective and personal. Its public display and private possession laid the basis for temporal autonomy: people could now coordinate comings and goings without dictation from above. The clock provided the punctuation marks for group activity, while enabling individuals to order their own work (and that of others) so as to enhance productivity. Indeed, the very notion of productivity is a by-product of the clock: once one can relate performance to uniform time units, work is never the same. One moves from the task-oriented time consciousness of the peasant (working one job after another, as time and light permit) and the time-filling busyness of the domestic servant (who always had something to do) to an effort to maximize product per unit of time.

　　Passage four

　　学科分类：生物学

　　题目：Prokaryote

　　内容回忆：讨论prokaryote原核生物和bacteria细菌，介绍了两个区别，prokaryote可以生存环境形劣地方，prokaryote的分类等

　　参考阅读：A prokaryote is a unicellular organism that lacks a membrane-bound nucleus, mitochondria, or any other membrane-bound organelle. The word prokaryote comes from the Greek πρό (pro) "before" and κάρυον (karyon) "nut or kernel". Prokaryotes are divided into two domains, Archaea and Bacteria. In contrast, species with nuclei and organelles are placed in the third domain, Eukaryota. Prokaryotes reproduce without fusion of gametes. The first living organisms are thought to have been prokaryotes.

　　In the prokaryotes, all the intracellular water-soluble components (proteins, DNA and metabolites) are located together in the cytoplasm enclosed by the cell membrane, rather than in separate cellular compartments. Bacteria, however, do possess protein-based bacterial microcompartments, which are thought to act as primitive organelles enclosed in protein shells. Some prokaryotes, such as cyanobacteria, may form large colonies. Others, such as myxobacteria, have multicellular stages in their life cycles.

　　Molecular studies have provided insight into the evolution and interrelationships of the three domains of biological species. Eukaryotes are organisms, including humans, whose cells have a well defined membrane-bound nucleus (containing chromosomal DNA) and organelles. The division between prokaryotes and eukaryotes reflects the existence of two very different levels of cellular organization. Distinctive types of prokaryotes include extremophiles and methanogens; these are common in some extreme environments.

　　Passage five

　　学科分类：生物学

　　题目：Mammal的迁徙

　　内容回忆：北方mammal和南方的mammal互相迁徙到对方区域，造成了lmbalanco，最后的小结题还要求总结了两种mammal目的特点，7选5的题型

　　参考阅读：Direct Species Translocation

　　It is becoming increasingly common for conservationists to move individual animals or entire species from one site to another. This may be either to establish a new population where a population of conspecifics (animals or plants belonging to the same species) has become extinct or to add individuals to an existing population. The former is termed reintroduction and the latter reinforcement. In both cases, wild individuals are captured in one location and translocated directly to another.

　　Direct translocation has been used on a wide range of plants and animals and was carried out to maintain populations as a source of food long before conservation was a familiar term. The number of translocations carried out under the banner of conservation has increased rapidly, and this has led to criticism of the technique because of the lack of evaluation of its efficacy and because of its potential disadvantages. The nature of translocation ranges from highly organized and researched national or international programs to ad hoc releases of rescued animals by well-intentioned animal lovers. In a fragmented landscape where many populations and habitats are isolated from others, translocations can play an effective role in conservation strategies; they can increase the number of existing populations or increase the size, genetic diversity, and demographic balance of a small population, consequently increasing its chances of survival.

　　Translocation clearly has a role in the recovery of species that have substantially declined and is the most likely method by which many sedentary species can recover all or part of their former range. However, against this is the potential for reinforcement translocations to spread disease from one population to another or to introduce deleterious or maladaptive genes to a population. Additionally, translocation of predators or competitors may have negative impacts on other species, resulting in an overall loss of diversity. Last but not least of these considerations is the effort and resources required in this type of action, which need to be justified by evidence of the likely benefits.

　　Despite the large number of translocations that have taken place, there is surprisingly little evidence of the efficacy of such actions. This is partly because many translocations have not been strictly for conservation; neither have they been official nor legal, let alone scientific in their approach. Successful translocations inevitably get recorded and gain attention, whereas failures may never be recorded at all. This makes appraisal of the method very difficult. One key problem is a definition of success. Is translocation successful if the individuals survive the first week or a year, or do they need to reproduce for one or several generations? Whatever the answer, it is clear that a general framework is required to ensure that any translocation is justified, has a realistic chance of success, and will be properly monitored and evaluated for the benefit of future efforts.

　　An example of apparent translocation success involves the threatened Seychelles warbler. This species was once confined to Cousin Island, one of the Seychelles islands, and reduced to 26 individuals. Careful habitat management increased this number to over 300 birds, but the single population remained vulnerable to local catastrophic events. The decision was taken to translocate individuals to two nearby islands to reduce this risk. The translocations took place in 1988 and 1990, and both have resulted in healthy breeding populations. A successful translocation exercise also appears to have been achieved with red howler monkeys in French Guiana. A howler population was translocated from a site due to be flooded for hydroelectric power generation. The release site was an area where local hunting had reduced the density of the resident howler population. Released troops of monkeys were kept under visual observation and followed by radio tracking of 16 females. Although the troops appeared to undergo initial problems, causing them to split up, all the tracked females settled into normal behavioral patterns.

　　Unfortunately, the success stories are at least matched by accounts of failure. Reviewing translocation of amphibians and reptiles, researchers C.Kenneth Dodd and Richard A. Siegel concluded that most projects have not demonstrated success as conservation techniques and should not be advocated as though they were acceptable management and mitigation practices.

　　所考词汇：uninterrupted / continuous

　　frigid / extremely cold

　　construed / interrupted

　　exclusively / only

　　relatively / fairly

　　imparting / giving

　　precise / accurate

　　painstaking / taking great effort in

　　imitator / people who copies him