TPO27-The Formation of Volcanic Islands

TPO27-Lecture1-MarineBiologyTPO27-Lecture 1- Marine BiologyNarratorListen to part of a lecture in a marine biology class.ProfessorSo we have been fairly thorough in our discussion about coral reefs, which of course are prominent, oceanic features made of hard limestone skeletons produced by tiny coral animals. We've gone over where coral reefs are usually formed - along the edges of shallow ocean banks in tropical or subtropical regions, and the fact that they are declining at an alarming rate. But I don't want to leave you with the impression that all is lost. There are several techniques being employed today that could prove useful in assuring the future of the reefs.Now, we've talked in depth about coral bleaching, or whitening, which as you recall, is a symptom of ...well that the coral is suffering. As you know, coral is very sensitive to water temperature. Even though one or two degree Celsius rise in sea surface temperature for a relatively short amount of time can cause bleaching. Recently, researchers have used data collected by monitoring surface water temperatures to improve the ability of a reef to recover from bleaching. One future possibility is that improved monitoring can help predict where and when bleaching will occur, which might potentially enable us to mitigate its effects.And there's another technique that's been experimented with to try to help coral reefs recover from bleaching. It's called coral transplantation. This involves moving young coral from a healthy reef onto a degraded reef, you know, in an attempt toregenerate the degraded reef by encouraging young healthy coral to take over. There has been some success with this, but it's still somewhat controversial. Some scientists support it because, well for one thing, it means you don't have to rely on the existing coral to reestablish itself because it might not be able to. But in my opinion, transplanting coral should only be used as ... well as a last resort. I mean, this method is not only costly but it's ... well even if it's successful, it still fails to address the ongoing problem, the root causes of the degradation, which really is paramount to devising an effective solution. So I don't really take comfort in the successes they have had with transplantation.Perhaps some more constructive use of our time could be spent at researching corals that do survive, like in areas known as refugia.Refugia are areas on the reef that are seemingly, well resistant to bleaching. See, when coral reefs experience bleaching, it's rarely a case of the whole reef being affected. There are almost always pockets of coral on the reefs that remain unaffected. And these are often the lower areas of the reef, those located in deeper water, where temperatures are lower.Now, we have evidence that corals in these locations are able to escape the destructive bleaching that affects portions of the reef in shallower or warmer water. So in my mind, it's these refugia that are the key components of overall reef resilience. These Would be the area of concentration for researchers to locate and protect those regions as a way to sustain coral reefs.And we can also protect the reefs by protecting the surrounding ecosystems, like mangrove forests and seagrass beds. Both of these grow in coastal waters, often in the vicinity of coral reefs. By protecting these areas, we also protect the coral. Let's take, for example, the mangrove forests. Mangrove rootsystems have the ability to absorb and well trap sediments and pollutants in water that flows through them before they enter the ocean. This of course has beneficial results for the nearby coral reefs.And fishery s management is another key strategy. Overfishing can be seriously disruptive to coral. Let me give you a couple of examples. Overfishing certain species offish and shellfish like snappers, barracudas and even lobsters. Well all of these creatures feed on snails, worms and other organisms that eat coral. So depleting the number of lobsters, for example, means that we are adding to the threat of coral decline. Sea urchins are another example. They eat algae and prevent it from overwhelming the coral. Since the disappearance of sea urchins from the waters up the coast of South Florida, many coral reefs there have been smothered by the uncontrolled growth of algae.。

Xiamen Volcano Island, also known as Huoshan Dao, is a unique geological wonder located in the southern part of Xiamen, a coastal city in Fujian Province, China. The island is renowned for its volcanic formations and pristine natural beauty, making it a popular destination for tourists and geology enthusiasts alike.Geological SignificanceThe island is a remnant of an ancient volcanic eruption that occurred millions of years ago. It features a variety of volcanic landforms, including craters, lava flows, and volcanic rocks. These geological features provide valuable insights into the earths geological history and the processes of volcanic activity.Scenic AttractionsXiamen Volcano Island boasts several scenic spots that showcase its natural beauty and geological wonders. Some of the notable attractions include:1. Crater Lake: A picturesque lake formed within the remnants of an ancient volcanic crater, offering stunning views of the surrounding landscape.2. Lava Flows: The island is home to wellpreserved lava flows that provide a glimpse into the power of volcanic eruptions.3. Volcanic Rock Formations: The island features various volcanic rock formations, such as columnar joints and pillow lavas, which are fascinating to observe and study.4. Coastal Scenery: The islands coastline offers breathtaking views of the sea, with clear waters and lush vegetation.Recreational ActivitiesVisitors to Xiamen Volcano Island can engage in various recreational activities, such as: 1. Hiking: The island offers several hiking trails that allow visitors to explore its natural beauty and geological features.2. Boating: Boat tours are available for those who wish to enjoy the islands coastal scenery from the water.3. Bird Watching: The island is home to various bird species, making it an ideal spot for bird watching enthusiasts.4. Photography: The islands stunning landscapes and geological features provide ampleopportunities for photography enthusiasts to capture beautiful images.Cultural SignificanceXiamen Volcano Island also holds cultural significance, as it is home to the ancient Huoshan Village. The village features traditional Fujianstyle architecture and offers a glimpse into the local culture and history.In conclusion, Xiamen Volcano Island is a remarkable destination that combines natural beauty, geological wonders, and cultural heritage. It offers a unique experience for visitors who are interested in exploring the earths geological history and enjoying the islands scenic attractions.。

island formation 托福真题Earth's surface is not made up of a single sheet of rock that forms a crust but rather a number of tectonic plates" that fit closely, like the pieces of a giant jigsaw puzzle. Some plates carry islands or continents others form the seafloor. All are slowly moving because the plates float on a denser semi-liquid mantle, the layer between the crust and Earth's core. The plates have edges that are spreading ridges (where two plates are moving apart and new seafloor is being created), subduction zones (where two plates collide and one plunges beneath the other), or transform faults (where two plates neither converge nor diverge but merely move past one another). It is at the boundaries between plates that most of Earth's volcanism and earthquake activity occur.Generally speaking, the interiors of plates are geologically uneventful. However, there are exceptions. A glance at a map of the Pacific Ocean reveals that there are many islands far out at sea that are actually volcanoes---many no longer active, some overgrown with coral---that originated from activity at points in the interior of the Pacific Plate that forms the Pacific seafloor.How can volcanic activity occur so far from a plate boundary? The Hawaiian Islands provide a very instructive answer. Like many other island groups, they form a chain. The Hawaiian Islands Chain extends northwest from the island of Hawaii. In the 1840s American geologistJames Daly observed that the different Hawaii islands seem to share a similar geologic evolution but are progressively more eroded, and therefore probable older, toward the northwest. Then in 1963, in the early days of the development of the theory of plate tectonics. Canadian geophysicist Tuzo Wilson realized that this age progression could result if the islands were formed on a surface plate moving over a fixed volcanic source in the interior. Wilson suggested that the long chain of volcanoes stretching northwest from Hawaii is simply the surface expression of a long-lived volcanic source located beneath the tectonic plate in the mantle. Today's most northwest island would have been the first to form. They as the plate moved slowly northwest, new volcanic islands would have forms as the plate moved over the volcanic source. The most recent island, Hawaii, would be at the end of the chain and is now over the volcanic source.Although this idea was not immediately accepted, the dating of lavas in the Hawaii (and other) chains showed that their ages increase away from the presently active volcano, just as Daly had suggested. Wilson's analysis of these data is now a central part of plate tectonics. Most volcanoes that occur in the interiors of plates are believed to be produced by mantle plumes, columns of molten rock that rise from deep within the mantle. A volcano remains an active hot spot" as long as it is over the plume. The plumes apparentlyoriginate at great depths,perhaps as deep as the boundary between the core and the mantle, and many have been active for a very long time. The oldest volcanoes in the Hawaii hot-spot trail have ages close to 80 million years. Other islands, including Tahiti and Easter Islands in the pacific, Reunion and Mauritius in the India Ocean, and indeed most of the large islands in the world's oceans, owe their existence to mantle plumes.The oceanic volcanic islands and their hot-spot trails are thus especially useful for geologist because they record the past locations of the plate over a fixed source. They therefore permit the reconstruction of the process of seafloor spreading, and consequently of the geography of continents and of ocean basins in the past. For example, given the current position of the Pacific Plate, Hawaii is above the Pacific Ocean hot spot. So the position of The Pacific Plate 50 million years ago can be determined by moving it such that a 50-million-year-oil volcano in the hot-spot trail sits at the location of Hawaii today. However because the ocean basins really are short-lived features on geologic times scale, reconstruction the world's geography by backtracking along thehot-spot trail works only for the last 5 percent or so of geologic time.Paragraph 1: Earth's surface is not made up of a single sheet of rock that forms a crust but rather a number of tectonic plates" that fit closely, like the pieces of a gain jigsaw puzzle. Some plates carry islands or continents, others form the seafloor. All are slowly moving because theplates float on a denser sem-iliquid mantle, the layer between the crust and Earth's core. The plates have edges that are spreading ridges (where two plates are moving apart and new seafloor is being created), subduction zones (where two plates collide and one plunges beneath the other), or transform faults (where two plates neither converge nor diverge but merely move past one another). It is at the boundaries between plates that most of Earth's volcanism and earthquake activity occur.1.The author mentions "spreading ridges",subduction zones", and transform faults" in order to illustrate that the boundaries of tectonic plates are neat, thin lines explain why some tectonic plates carry islands or continents while others form theseafloor.2.explain the complex nature of the edges of tectonic platesprovide examples of areas of tectonic plates where little geologic action occurs3.The word converge" in the passage is closest in meaning toA.expandB.formC.rise。

智课网TOEFL备考资料托福TPO阅读真题及译文：Savanna Formation摘要：本篇小编大家分享托福TPO阅读真题及译文：Savanna Formation，最后附有中文翻译，希望考生们可以参考使用!扫描二维码下载→_→ 托福 TPO阅读真题及译汇总一手掌握小马机经APP新版福利上线了！绝对堪称托福学子备考必备利器，扫描左侧二维码下载DUANG的一下托福机经、录音、解析、答案参考、历年真题全部出来啦！光是独立口语机经就有60套重点题目，心动就赶快下载吧！第一段：托福TPO阅读原文：Located in tropical area at low altitudes, savannas are stable ecosystems, some wet and some dry consisting of vast grasslands with scattered tree or shrubs. They occur on a wide range of soil types and in extremes of climate. There is no simple or single factor that determines if a given site will be a savanna, but some factors seem to play important roles in their formation.托福TPO阅读翻译：热带草原或热带稀树草原位于热带低海拔地区，干湿气候皆有。

稀疏分布着树木和灌木的广阔大草原，其为一个稳定的生态系统。

气候极端，涵盖了广泛的土壤种类。

对于热带草原的形成原因，虽无单一的解释，但似乎仍有一些因素对其形成起到了重大作用。

第二段：托福TPO阅读原文：Savannas typically experience a rather prolonged dry season. One theory behind savanna formation is that wet forest species are unable to withstand the dry season, and thus savanna, rather than rain forest, is favored on the site. Savannas experience an annual rainfall of between 1000 and 2000 millimeters, most of it falling in a five-to-eight month wet season. Though plenty of rain may fall on a savanna during the year, for at least part of the year little does, creating the drought stress ultimately favoring grasses. Such conditions prevail throughout much of northern South America and Cuba, but many Central American savannas as well as coastal areas of Brazil and the island of Trinidad do not fit this pattern. In these areas, rainfall per month exceeds that in the above definition, so other factors must contribute to savanna formation.托福TPO阅读翻译：热带草原通常会经历十分漫长的旱季。

TPO69阅读-2Pacific Ecosystems原文 (1)译文 (2)题目 (4)答案 (8)背景知识 (9)原文Pacific Ecosystems①The Pacific Ocean accounts for one-third of Earth’s surface and half of the world’s ocean area.It has about25,000islands,of which about7,500are oceanic,being relatively far from a continental shore.The great majority of all Pacific islands were born barren of life:hard,dense,volcanic rock pimples on the sea's surface.New Zealand is the chief exception;it is among the continental islands of the western Pacific,together with Fiji,the Solomons,and others to the west.②Life arrived on most other islands by accident or by drift.Some plants arrived by air transport;seeds carried in the digestive tracts of birds account for nearly40 percent of Hawaii's early plants.The first invaders were either creatures that could float well enough,in air or water,to cross stretches of ocean,or those whose seeds could survive a voyage in some bird's gut.At times of lower sea level,land bridges linked,or nearly linked,many islands in the far western Pacific,so some species colonized these islands without being notably good floaters or stowaways.In the eastern Pacific(Easter Island,for example)only the best floaters and travelers arrived and survived.Consequently,the western islands have far more species and far greater biodiversity than do the eastern islands of Polynesia.Mammals found it hard to get anywhere in the island Pacific;only bats and rats successfully colonized east of New Guinea.Almost all species derive from Asia;the early Pacific was an Asian lake,with only a tiny proportion of species from the Americas.As a rule of thumb,the further from Indonesia,the more impoverished the plant and animal life and,in consequence,the less stable and resilient in the face of disturbance. This attenuation is strong for land species,less strong for marine species,and nonexistent for oceanic birds,although fairly strong for land birds.③Pacific ecosystems evolved in relative(but differential)isolation from the continental crucibles of biological evolution.This meant opportunities for speciation:the development of new species occupying ecological niches that elsewhere were already filled.The finches described by the naturalist Charles Darwin on the Galapagos Islands—birds that divided into different species,each specialized for a narrow niche—are the classic example.On islands that had no mammals,reptiles and birds took their place.Thus the Galapagos have giant tortoises,and New Zealand once had giant birds that functioned more or less like browsing or grazing mammals.Throughout most of the Pacific,the paucity of grazing animals meant that plants developed no defenses,such as spines, poisonous chemicals,or bitterness.The remoter islands had a very high proportion of endemism—that is，of species that existed only there.In the case of Hawaii,as many as99percent of the species were endemic.All this led to a certain biological vulnerability among the terrestrial island species,should they ever be obliged to compete for niche space with the winners of the more intense continental competitions for survival.This vulnerability increased toward the east and toward the remoter corners of the Pacific along a gradient defined chiefly by the degree of isolation.④A second source of vulnerability,perhaps more decisive,arose from the arrival of humankind in the Pacific.Island animals evolved with no experience of the ways of humankind,or indeed of any large terrestrial predators.As a result,they had no immunities to predators or the effects of human action.Pacific animals were often unwary and easy prey.At the extreme,again the Galapagos,Darwin found many birds almost tame,so naively trusting that they would allow him to get within arm’s reach.Pacific plants had little experience with fire,because natural fires were very rare,except in a few places.Thus few plants were well adapted to fire,and most proved vulnerable to it.In contrast,continental species that had evolved in the presence of humankind,or in places where natural fire is much more common, could recover easily after burns,and some could flourish as a result of fire.In short, Pacific ecosystems were different from continental ones on account of their isolation.They were well adapted to their circumstances but very vulnerable to alien invasion and human impact.译文太平洋生态系统①太平洋占地球表面的三分之一，占世界海洋面积的一半。

阅读原文：?The greater Pacific region, traditionally called Oceania, consists of three cultural areas: Melanesia, Micronesia, and Polynesia. Melanesia, in the southwest Pacific, contains the large islands of New Guinea, the Solomons, Vanuatu, and New Caledonia. Micronesia, the area north of Melanesia, consists primarily of small scattered islands. Polynesia is the central Pacific area in the great triangle defined by Hawaii, Easter Island, and New Zealand. Before the arrival of Europeans, the islands in the two largest cultural areas, Polynesia and Micronesia, together contained a population estimated at 700,000.Speculation on the origin of these Pacific islanders began as soon as outsiders encountered them, in the absence of solid linguistic, archaeological, and biological data, many fanciful and mutually exclusive theories were devised. Pacific islanders are variously thought to have come from North America, South America, Egypt, Israel, and India, as well as Southeast Asia. Many older theories implicitly deprecated the navigational abilities and overall cultural creativity of the Pacific islanders. For example, British anthropologists G. Elliot Smith and W. J. Perry assumed that only Egyptians would have been skilled enough to navigate and colonize the Pacific. They inferred that the Egyptians even crossed the Pacific to found the great civilizations of the New World (North and South America). In 1947 Norwegian adventurer Thor Heyerdahl drifted on a balsa-log raft westward with the winds and currents across the Pacific from South America to prove his theory that Pacific islanders were Native Americans (also called American Indians). Later Heyerdahl suggested that the Pacific was peopled by three migrations: by Native Americans from the Pacific Northwest of North America drifting to Hawaii, by Peruvians drifting to Easter Island, and by Melanesians. In 1969 he crossed the Atlantic in an Egyptian-style reed boat to prove Egyptian influences in the Americas. Contrary to these theorists, the overwhelming evidence of physical anthropology, linguistics, and archaeology shows that the Pacific islanders came from Southeast Asia and were skilled enough as navigators to sail against the prevailing winds and currents.The basic cultural requirements for the successful colonization of the Pacific islands include the appropriate boat-building, sailing, and navigation skills to get to the islands in the first place, domesticated plants and gardening skills suited to often marginal conditions, and a varied inventory of fishing implements and techniques. It is now generally believed that these prerequisites originated with peoples speaking Austronesian languages (a group of several hundred related languages) and began to emerge in Southeast Asia by about 5000 B.C.E. The culture of that time, based on archaeology and linguistic reconstruction, is assumed to have had a broad inventory of cultivated plants including taro, yarns, banana, sugarcane, breadfruit, coconut, sago, and rice. Just as important, the culture also possessed the basic foundation for an effective maritime adaptation, including outrigger canoes and avariety of fishing techniques that could be effective for overseas voyaging.Contrary to the arguments of some that much of the pacific was settled by Polynesians accidentally marooned after being lost and adrift, it seems reasonable that this feat was accomplished by deliberate colonization expeditions that set out fully stocked with food and domesticated plants and animals. Detailed studies of the winds and currents using computer simulations suggest that drifting canoes would have been a most unlikely means of colonizing the Pacific. These expeditions were likely driven by population growth and political dynamics on the home islands, as well as the challenge and excitement of exploring unknown waters.Because all Polynesians, Micronesians, and many Melanesians speak Austronesian languages and grow crops derived from Southeast Asia, all these peoples most certainly derived from that region and not the New World or elsewhere. The undisputed pre-Columbian presence in Oceania of the sweet potato, which is a New World domesticate, has sometimes been used to support Heyerdahl’s “American Indians in the Pacific” theories. However, this is one plant out of a long list of Southeast Asian domesticates. As Patrick Kirch, an American anthropologist, points out, rather than being brought by rafting South Americans, sweet potatoes might just have easily been brought back by returning Polynesian navigators who could have reached the west coast of South America.中文翻译：广义的太平洋地区，传统上被称作大洋洲，由三块文化区域组成：美拉尼西亚，密克罗尼西亚和波利尼西亚。

【托福写作资料】TPO27综合写作文本与解析TPO综合写作范文是考生练习托福写作的必备资料，很多考生在网上求这份资料。

那么，在以下内容中，就为大家带TPO综合写作文本与解析，希望能为大家的备考带来帮助。

托福TPO27综合写作题目 Reading Part:The little ice age was a period of unusually cold temperature in many partsof the world that lasted from about the year 1350 until 1900CE. There wereunusually harsh winters, and glaciers grew larger in many areas. Scientist havelong wondered what caused the Little Ice Age. Several possible causes have beenproposed.First, the cooling may have been caused by disrupting of ocean currents.Before the Little Ice Age, there was a period of unusually warm weather duringwhich glaciers melted. These melted glaciers sent a large amount of coldfreshwater into the Gulf Stream, a large ocean current that strongly affectsEarth’s climate. Some scientists believe that this freshwater was enough totemporarily disrupt the Gulf Stream. Such a disruption could have caused theLittle Ice Age.Second, volcanic eruption could have caused the Little Ice Age. Whenvolcanoes erupt, they send dark clouds of dust and sulfur gas into theatmosphere. These clouds, which can spread over great areas, block some sunlightfrom reaching Earth’s surface. This can decrease the global temperatures.Scientists know of several volcanic eruption that took place during the LittleIce Age.Third, substantial decreases in human populations may have contributedindirectly to the cooling of the climate. For a variety of reason(disease, warfare, social disruption), the human population just before the Little Ice Age and during the early part of it was lower than it had been in a long time.Forest trees started growing on fields that were no longer used for agriculture.Since trees absorb carbon dioxide, a greenhouse gas, they decrease thegreenhouse effect that keeps Earth warm. With more forest trees carbon dioxide, earth became cooler.托福TPO27综合写作题目 Listening Part:Unfortunately，the arguments of the reading passage are a little out of date.Scientists now have new information that shows that none of the ideas the reading passage discusses could account for the Little Ice Age.First，about the Gulf Stream.Scientists now know that disrupting the Gulf Stream would cause cooling only in Europe and North America，but the Little Ice Age also affected the Southern hemisphere，in places like New Zealand and Southern Africa for example.Since the disruption of the Gulf Stream cannot explain why these southern areas became colder，it cannot explain the Little Ice Age.Second, the volcanoes theory.It’s true that if volcanic eruptions put enoughdust into the atmosphere.the result can be a cooler climate.But large amounts ofvolcanic dust in the atmosphere would have also produced striking visual effectthat people would have noticed at the time.For example.Dramatically colorfulSunsets or snow being grey or brown instead of white.But there are almost no reports of anything like that routinely happening during the Little Ice Age.So it seems that the volcanic eruptions during that period were simply not strong enough to release the large amounts of dust needed to lower globaltemperatures.Third, about forests on farmland stopping the warming greenhouse effect by removing carbon dioxide.There just was not enough time for this effect to work.The human population grew back to previous levels fairly quickly，which meant that forests were soon being cut down again to clear fields for the crops needed to feed the growing population.As a result，we know that the forests mentioned in the reading passage were not there long enough to cause the long—term global cooling of the climate.托福TPO27综合写作题目 Question:Summarize the point made in the lecture ， being sure to explain how the cast doubt on specific points made in the reading passage.托福TPO27综合写作答案解析：In the reading passage, the author claims that the cause of the Little IceAge was due to three main reasons. The lecturer, however, reputes the writer’sopinion one by one with strong arguments.Firstly, the passage argues that the Gulf Stream formed in the previous warmperiod was responsible for the appearance of the unexpected Little Ice Age. Yet, the speaker argues that the so-called Gulf Stream only contributed to the cooling weather in Northern hemisphere while Little Ice Age took place all over the world. Thus, global Little Ice Age cannot be Next, according to the reading material, dust and sulfur gas caused by volcanic eruptions would block sunlight, and resulted in Little Ice Age. he lecturer, however, holds that volcanic eruptions should have led to other visual phenomena than cooling weather, like colorful sunsets or grey snow. But unfortunately none of them were reported. Once taken this into consideration, volcanic eruptions seems not strong enough to release the large amounts of dusts needed to lower global temperatures. Last but not least, the writer states that the substantial decrease in human population may cause the unusual Little Ice Age. Again the speaker argues.。

TPO-42Geographic Isolation of SpeciesBiologist Ernst Mayr defined a species as “an actually or potentially interbreeding populationevent 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 followseems 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.Too many words you don’t know? Look them up in《新托福TPO阅读词汇速查速记》!Wechat: geeqi0805How 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, separate the range of the while-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 Hams' 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 notenough 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 theSouth American mainland 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. Eachisland 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 isla nd, 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. ■A. earlyB. crucialC. noticeableD. frequentA. bestB. usualC. firstD. actualYou enjoy the convenience of having all vocabulary questions listed as a separate part in《新托福TPO阅读词汇速查速记》.3. According to paragraph 1, allopatric speciation is possible whenA. a population contains all the different genes present in a species at a particular timeB. a population becomes isolated due to the presence of a geographic barrierC. genetic mixing begins to occur in previously separate populations of a speciesD. a species is successful in crossing a geographic barrier4. How is paragraph 2 related to paragraph 1?A. Paragraph 2 points out a number of ways in which the phenomenon of geographic isolation mentioned in paragraph 1 can occurB. Paragraph 2 identifies discoveries that led to the conclusion presented in paragraph 1 that geographic isolation has played a role in the origin of many speciesC. Paragraph 2 provides evidence supporting the statement in paragraph 1 that a population can follow its own evolutionary course once its gene pool becomes isolatedD. Paragraph 2 explains why the term “allopatric” was adopted to describe t he method of speciation described in paragraph 15. In paragraph 3, the author contrasts a variety of organisms to illustrate which of the following points?A. Geographic barriers are less likely to keep apart populations of plants than populations of animalsB. Geographic barriers are more likely to keep apart populations of large organisms than populations of small organismsC. Some members of a species are able to cross geographic barriers, while other members of the same species are notD. The effectiveness of geographic barriers in keeping organisms apart depends on an organism’s ability to move across barriers6. Paragraph 3 supports the idea that white-tailed antelope squirrels and Hams' antelope squirrels have which of the following in common?A. They are the two smallest rodents now found in the southwestern United States.B. They have white coloring underneath their tailsC. They cannot cross the Grand CanyonD. They cannot survive in desert conditionsA. experiencesB. allowsC. preventsD. causes8. Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential informationA. Geographic isolation is sometimes but not always the reason for the creation of reproductive barriers between a parent population and the populations descended from itB. Genetic changes in a geographical isolated population do not necessarily make the population look different enough from its parent population to be considered a new speciesC. Geographical isolation allows the separated populations to evolve independently of each other and so can lead to the formation of new speciesD. Geographic isolation can lead to new species only if the gene pool of the isolated population changes enough to prevent it from reproducing with the parent population9. According to paragraph 4, why does the size of a population affect the likelihood of allopatric speciation?A. Because smaller populations are more likely than larger ones to become geographically isolatedB. Because the gene pool of a small isolated population is more likely to undergo substantial change than is the gene pool of a larger populationC. Because an isolated population can become a new species with substantially less change to its gene pool than would be required by a larger populationD. Because smaller populations are more likely to be made up of stray animals or plants than larger populations areA. were ableB. were forcedC. arrivedD. expanded11. Paragraph 5 supports the idea that the Galapagos island chain was able to become “one of the world's g reatest showcases of evolution” primarily because ofA. the richness of the volcanic soil of each of the islands in the chainB. the distance of the individual islands from each other and from the mainlandC. the relativity long time it took for the islands to become covered by organismsD. the outdoor laboratories that scientists have built on the islands to study evolution12. According to paragraph 6, what is true about the thirteen species of Galapagos finches?A. All thirteen species are now found on most of the Galapagos IslandsB. All thirteen species are descended from the same population of ancestral birdsC. All thirteen species evolved on the island that was originally colonized by finches from the mainland.D. All thirteen species occur only in small, completely isolated populations.13. Look at the four squares [█] that indicate where the following sentence could be added to the passageThis process of speciation and colonization could have been repeated over and over again, gradually involving all the islands in the chain.Where would the sentence best fit? Click on a square to add the sentence to the passage.14. 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 most important ideas in the passage. Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. The question is worth 2 points.The geographic isolation of a population can result in the rise of a new species.●●●Answer Choices○ Isolation can result when a geographic barrier forms and splits a population or when a few organisms somehow get carried across an existing geographic barrier and form a new population ○ Speciation is more likely when an isolated population is small because significant genetic changes are more likely to occur in a small population than in a large one○ Because of the geographic isolation of th e Galapagos Islands, the species that now inhabit them have gene pools that have not changed very much since the islands were first populated.○ Fish populations are more easily isolated by geographic barriers than are populations of most other organisms because fish cannot move across areas where there is no water.○ The Galapagos Islands are well situated for speciation because they provide opportunities for population isolation while also making occasional dispersions between islands possible.○ Evidence indicates that the first organisms to reach the Galapagos Islands were probably a small population of finches that, in less than two million years of isolation, evolved into thirteen species.答案：1-5: B C B A D 6-10:C A D B A 11-14: B B C A B EIf you have any questions concerning the texts or answers, feel free to contact Wechat: geeqi0805. If you are tired of looking up TPO words in a dictionary, try《新托福TPO阅读词汇速查速记》!参考译文：物种的地理隔离生物学家厄恩斯特·迈尔将物种定义为“一个可以互相交配或可能互相交配的群体，但这个群体不能与其它生物交配，即便有交配的机会”。

岛屿变迁雅思作文英文回答：Climate change and the subsequent rise in sea levels have profound implications for coastal areas worldwide. As the ocean encroaches on land, islands face the threat of submergence or erosion. The future of island communities depends on their ability to adapt to these changes, which requires a multifaceted approach involving both physical and social measures.Physical measures to protect islands from sea-levelrise include building seawalls, dykes, and other coastal defenses. These structures can physically block the ocean from reaching inland areas and are particularly effective in protecting low-lying coastal areas. However, the construction and maintenance of such infrastructure can be costly and may not always be feasible, especially for small or vulnerable islands.Social measures focus on adjusting human activities and behaviors to mitigate the impacts of sea-level rise. This can include relocating communities away from vulnerable areas, implementing land-use planning regulations torestrict development in high-risk zones, and educating residents about the risks and adaptation measures. Social measures are often more cost-effective than physical measures and can provide long-term solutions to the challenges posed by sea-level rise.In addition to these measures, island communities may also need to consider the option of managed retreat. This involves abandoning low-lying areas that are at high riskof inundation and relocating to higher ground. Managed retreat can be a difficult and emotional decision, but it may be necessary to ensure the long-term survival of island communities in the face of rising sea levels.While the specific measures that are appropriate for a particular island will vary depending on its unique circumstances, it is clear that a comprehensive approach is necessary to address the challenges posed by sea-level rise.Island communities must work together to develop and implement adaptation plans that protect their land, their people, and their way of life.中文回答：气候变化和随之而来的海平面上升对世界各地的沿海地区产生了深远的影响。