A conjecture on centauro species
怎样阻止物种灭绝英文作文
怎样阻止物种灭绝英文作文英文：How to Prevent Species Extinction。
Species extinction is a critical issue facing our planet today, and it's imperative that we take action to prevent further loss of biodiversity. Here, I'll discuss some effective strategies to address this pressing concern.First and foremost, habitat conservation is paramountin preserving species diversity. Many species face extinction due to habitat destruction caused by human activities such as deforestation, urbanization, and pollution. By protecting and restoring natural habitats, we can provide safe havens for endangered species to thrive. For instance, the conservation efforts in Yellowstone National Park have helped restore populations of wolves and grizzly bears, which were once on the brink of extinction.Secondly, sustainable resource management is essential for maintaining healthy ecosystems. Overexploitation of natural resources, such as overfishing and illegal logging, can drive species to extinction. Implementing quotas, regulations, and monitoring systems can help ensure that resource extraction is done responsibly and does not harm vulnerable species. Take the example of the North Atlantic cod fishery collapse, which resulted from overfishing and inadequate management practices. By enforcing sustainable fishing practices, we can prevent similar catastrophes from occurring in the future.Furthermore, combating climate change is crucial for safeguarding biodiversity. Climate change alters habitats, disrupts ecosystems, and exacerbates existing threats to species survival. Transitioning to renewable energy sources, reducing greenhouse gas emissions, and implementing climate adaptation strategies can help mitigate the impacts of climate change on wildlife. For instance, the conservationof mangrove forests not only protects coastal areas from storm surges but also sequesters carbon dioxide, mitigating climate change effects.In addition to these proactive measures, raising awareness and promoting environmental education are vital for fostering a culture of conservation. People need to understand the value of biodiversity and the interconnectedness of all living organisms. Through educational programs, community engagement initiatives, and media campaigns, we can inspire individuals to take action to protect endangered species and their habitats. For example, documentaries like "Our Planet" and "Planet Earth" have raised global awareness about the importance of preserving natural ecosystems.In conclusion, preventing species extinction requires a multifaceted approach that addresses habitat conservation, sustainable resource management, climate change mitigation, and public engagement. By implementing these strategies effectively, we can safeguard the rich tapestry of life on Earth for future generations to enjoy.中文：如何防止物种灭绝。
外来物种的英语阅读理解
外来物种的英语阅读理解Here is an English essay on the topic of "Invasive Species" with a word count over 1000 words, as per your instructions. The essay is written in English without any additional title or punctuation marks.Invasive SpeciesThe global ecosystem is a delicate balance of diverse flora and fauna that have coexisted for centuries, adapting to the unique characteristics of their native environments. However, this equilibrium is increasingly being disrupted by the introduction of non-native or "invasive" species - organisms that are brought, either intentionally or unintentionally, to regions outside of their natural habitats. These invasive species can have devastating consequences on local ecosystems, posing a significant threat to native wildlife, agricultural productivity, and even human health.One of the primary drivers of invasive species introduction is human activity. As globalization has accelerated, the movement of people, goods, and materials across international borders has increased exponentially. This has led to the unintentional transport of non-native organisms, which can stow away in shipping containers, onvehicles, or even in the soil of imported plants. Additionally, the deliberate introduction of certain species for agricultural, horticultural, or recreational purposes has sometimes resulted in those organisms escaping or being released into the wild, where they can thrive and outcompete indigenous species.The impacts of invasive species can be far-reaching and profound. These non-native organisms often lack natural predators or competitors in their new environments, allowing them to rapidly multiply and spread unchecked. This can disrupt the delicate food webs and ecological niches that support native species, leading to the decline or even extinction of indigenous flora and fauna. Invasive plants, for example, can aggressively outcompete native vegetation, altering the composition of natural habitats and depriving native animals of essential resources.The economic consequences of invasive species can also be significant. Invasive pests and pathogens can wreak havoc on agricultural crops, forests, and other valuable resources, resulting in substantial financial losses for farmers, foresters, and resource managers. The control and eradication of invasive species can also be extremely costly, often requiring intensive and sustained efforts over many years.Moreover, the introduction of non-native species can have seriousimplications for human health. Certain invasive organisms, such as disease-carrying insects or toxic plants, can pose direct threats to human well-being, leading to the spread of infectious diseases or the accidental poisoning of individuals. In some cases, the impacts of invasive species on ecosystems can also indirectly impact human communities, disrupting the availability of essential resources or the integrity of natural landscapes that provide valuable ecosystem services.In response to the growing threat of invasive species, governments, conservation organizations, and scientific communities have developed a range of strategies and policies aimed at prevention, early detection, and rapid response. Border control measures, such as inspections and quarantine procedures, can help to intercept and prevent the introduction of non-native organisms. Robust monitoring and surveillance systems can also aid in the early identification of invasive species, allowing for more effective intervention before they become firmly established.Once an invasive species has become established, the options for management and control can be more challenging. Eradication efforts may involve the use of targeted pesticides, biological control agents, or even manual removal of the invasive organisms. In some cases, the relocation or reintroduction of native predators or competitors can help to restore the ecological balance. However,these approaches require careful planning, extensive resources, and long-term commitment to ensure their effectiveness.Ultimately, the prevention and management of invasive species will require a multifaceted approach that combines scientific research, policy development, public education, and international cooperation. By raising awareness about the threats posed by non-native organisms and implementing robust biosecurity measures, we can work to protect the integrity of our natural ecosystems and safeguard the long-term sustainability of our shared environment.。
2023年高考英语外刊时文精读专题01生物多样性保护
2023年高考英语外刊时文精读精练 (1)Biodiversityconservation conversation生物多样性保护对话主题语境：人与自然 主题语境内容：人与环境，人与动植物【外刊原文】（斜体单词为超纲词汇，认识即可；下划线单词为课标词汇，需熟记。
）the tone for COP15,the largest UN biodiversity gathering in a decade. The conference, taking place in two parts, is being hosted by China for thebe postponed（推迟）. The host city is the capital of Yunnan, a south-western province that is a showcase(展示) of the biodiversity that China needscooperation on limiting emissions (排放).The theme for Kunming is（生态文明）”.The term was written into China’s constitution (宪法) in 2018, suggesting how central it now is in guiding development.The Kunming declaration is filled with other favourite greening concepts of Beijing,including the“two-mountains theory”. This states that “green mountains are gold mountains”:wildlife and habitats.More than one in five surviving speciesmangroves (红树林)disappeared.Some 90%of grasslands are at varying stages of degradation（退化） or desertification（荒漠化）, and almost half ofYet, despite the damage of urbanization（城市化）, China has much left to protect. It is home to 10% of the world’s plant species, 14% of animal onesand 20%of fish.At the second meeting, representatives will set goals for 2030 to preserve global plant and animal life. In October China's Presidentformal opening of five national parks, covering 230,000 sq km, home to over a quarter of China’s terrestrial(陆生的)wildlife species.country to carbon neutrality（碳中和） by 2060.Then in September hefor now, China remains the largest consumer of coal and emitter of carbon dioxide.Greenpeace called the Kunming declaration “a toothless tiger”.Keeping citizens happy is becoming a powerful incentive（动机） for China.They are complaining about more than polluted waterfocus on the costs of destroying habitats and trading wildlife.In【课标词汇】1.approval 赞成；同意；称许•He showed his approval by smiling broadly.他持赞成的态度，这从他开心的微笑就看得出来。
tpo32三篇托福阅读TOEFL原文译文题目答案译文背景知识
tpo32三篇托福阅读TOEFL原文译文题目答案译文背景知识阅读-1 (2)原文 (2)译文 (5)题目 (7)答案 (16)背景知识 (16)阅读-2 (25)原文 (25)译文 (28)题目 (31)答案 (40)背景知识 (41)阅读-3 (49)原文 (49)译文 (53)题目 (55)答案 (63)背景知识 (64)阅读-1原文Plant Colonization①Colonization is one way in which plants can change the ecology of a site.Colonization is a process with two components:invasion and survival.The rate at which a site is colonized by plants depends on both the rate at which individual organisms(seeds,spores,immature or mature individuals)arrive at the site and their success at becoming established and surviving.Success in colonization depends to a great extent on there being a site available for colonization–a safe site where disturbance by fire or by cutting down of trees has either removed competing species or reduced levels of competition and other negative interactions to a level at which the invading species can become established.For a given rate of invasion,colonization of a moist,fertile site is likely to be much more rapid than that of a dry, infertile site because of poor survival on the latter.A fertile,plowed field is rapidly invaded by a large variety of weeds,whereas a neighboring construction site from which the soil has been compacted or removed to expose a coarse,infertile parent material may remain virtually free of vegetation for many months or even years despite receiving the same input of seeds as the plowed field.②Both the rate of invasion and the rate of extinction vary greatly among different plant species.Pioneer species-those that occur only in the earliest stages of colonization-tend to have high rates of invasion because they produce very large numbers of reproductive propagules(seeds,spores,and so on)and because they have an efficient means of dispersal(normally,wind).③If colonizers produce short-lived reproductive propagules,they must produce very large numbers unless they have an efficient means of dispersal to suitable new habitats.Many plants depend on wind for dispersal and produce abundant quantities of small,relatively short-lived seeds to compensate for the fact that wind is not always a reliable means If reaching the appropriate type of habitat.Alternative strategies have evolved in some plants,such as those that produce fewer but larger seeds that are dispersed to suitable sites by birds or small mammals or those that produce long-lived seeds.Many forest plants seem to exhibit the latter adaptation,and viable seeds of pioneer species can be found in large numbers on some forest floors. For example,as many as1,125viable seeds per square meter were found in a100-year-old Douglas fir/western hemlock forest in coastal British Columbia.Nearly all the seeds that had germinated from this seed bank were from pioneer species.The rapid colonization of such sites after disturbance is undoubtedly in part a reflection of the largeseed band on the forest floor.④An adaptation that is well developed in colonizing species is a high degree of variation in germination(the beginning of a seed’s growth). Seeds of a given species exhibit a wide range of germination dates, increasing the probability that at least some of the seeds will germinate during a period of favorable environmental conditions.This is particularly important for species that colonize an environment where there is no existing vegetation to ameliorate climatic extremes and in which there may be great climatic diversity.⑤Species succession in plant communities,i.e.,the temporal sequence of appearance and disappearance of species is dependent on events occurring at different stages in the life history of a species. Variation in rates of invasion and growth plays an important role in determining patterns of succession,especially secondary succession. The species that are first to colonize a site are those that produce abundant seed that is distributed successfully to new sites.Such species generally grow rapidly and quickly dominate new sites, excluding other species with lower invasion and growth rates.The first community that occupies a disturbed area therefore may be composed of specie with the highest rate of invasion,whereas the community of the subsequent stage may consist of plants with similar survival ratesbut lower invasion rates.译文植物定居①定居是植物改变一个地点生态环境的一种方式。
2023年高考英语外刊时文精读专题14气候变化与珊瑚礁
2023年高考英语外刊时文精读精练 (14)Climate change and coral reefs气候变化与珊瑚礁主题语境：人与自然主题语境内容：自然生态【外刊原文】（斜体单词为超纲词汇，认识即可；下划线单词为课标词汇，需熟记。
）Human beings have been altering habitats—sometimes deliberately andsometimes accidentall y—at least since the end of the last Ice Age. Now, though, that change is happening on a grand scale. Global warming is a growing factor. Fortunately, the human wisdom that is destroying nature can also be brought to bear on trying to save it.Some interventions to save ecosystems are hard to imagine andsucceed. Consider a project to reintroducesomething similar to a mammoth(猛犸象)to Siberiaby gene-editing Asian elephants. Their feeding habits could restore the grassland habitat that was around before mammoths died out, increasing the sunlight reflected into space and helping keep carbon compounds(碳化合物)trapped in the soil. But other projects have a bigger chance of making an impact quickly. As we report, one example involves coral reefs.These are the rainforests of the ocean. They exist on vast scales: half a trillion corals line the Pacific from Indonesia to French Polynesia, roughly the same as the number of trees that fill the Amazon. They are equally important harbor of biodiversity. Rainforests cover18% of the land’s s urface and offer a home to more than half its vertebrate(脊椎动物的)species. Reefs occupy0.1% of the oceans and host a quarter of marine(海洋的)species.And corals are useful to people, too. Without the protection which reefs afford from crashing waves, low-lying islands such as the Maldives would have flooded long ago, and a billion people would lose food or income. One team of economists has estimated that coral’s global ecosystem services are worth up to $10trn a year. reefs are, however, under threat from rising sea temperatures. Heat causes the algae（海藻） with which corals co-exist, and on which they depend for food and colour, to generate toxins（毒素）that lead to those algae’s expulsion（排出）. This is known as “bleaching（白化）”, and can cause a coral’s death.As temperatures continue to rise, research groups around the world are coming up with plansof action. Their ideas include identifying naturally heat-resistant（耐热的）corals and moving themaround the world; crossbreeding（杂交）such corals to create strains that are yet-more heat-resistant; employing genetic editing to add heat resistance artificially; transplantingheat-resistant symbiotic（共生的）algae; and even repairing with the bacteria and other micro-organismswith which corals co-exist—to see if that will help.The assisted evolution of corals does not meet with universal enthusiasm. Without carbon reduction and decline in coral-killing pollution, even resistant corals will not survive the century. Some doubt whetherhumans will get its act together in time to make much difference. Few of these techniques are ready for action in the wild. Some, such as gene editing, are so controversial that it is doubtful they will be approved any time soon. scale is also an issue.But there are grounds for optimism. Carbon targets are being set and ocean pollution is being dealt with. Countries that share responsibilities for reefs are starting to act together. Scientific methods can also be found. Natural currents can be used to facilitate mass breeding. Sites of the greatest ecological and economical importance can be identified to maximise benefits.This mix of natural activity and human intervention could serve as a blueprint （蓝图）for other ecosystems. Those who think that all habitats should be kept original may not approve. But when entire ecosystems are facing destruction, the cost of doing nothing is too great to bear. For coral reefs, at least, if any are to survive at all, it will be those that humans have re-engineered to handle the future.【课标词汇精讲】1.alter （通常指轻微地）改动，修改；改变，（使）变化We've had to alter some of our plans.我们不得不对一些计划作出改动。
新托福综合写作范文-阻止甘蔗蟾蜍在澳洲扩散的措施
The writer believes that several measures proposed will be effective to prevent the cane toad from spreading in Australia. However, the lecturer casts doubts on those methods and refutes that they are actually unsuccessful and may cause environmental damage.Firstly, the passage suggests that national fence should be built to block the movement of the toads. The lecturer agrees it may have effects on grown-up toads, but it is fruitless in terms of young toads and their eggs, because streams and rivers will carry the young and eggs to the other side of the waters. Therefore, national fence is not so effective as is proposed.Secondly, the lecturer also believes it won't achieve success for volunteers to capture or destroy the cane toads. She explains that most volunteers are untrained, so they may also cause damage to other species living in the same areas, and some are already endangered.Lastly, the method of developing a disease-causing virus to control the toad populations will cause very terrible consequences, as the lecturer warns. The virus will actually do harm to the habitat in America and destroy the cane toads there since the virus can be spread through various channels. If the toads in America are eliminated, the ecosystem there will definitely suffer.。
2012年职称英语理工A新增阅读理解押题
2012年职称英语理工A新增阅读理解押题第一篇：2012年职称英语理工A新增阅读理解押题+第四＋五篇Small But Wise On December 14,NASA1 blasted a small but mighty telescope into space.The telescope is called WISE and is about as wide around as a trashcan.Don't let its small size fool you:WISE has a powerful digital camera, and it will be taking pictures of some the wildest objects2 in the known universe,including asteroids,faint stars,blazing galaxies3 and giant clouds of dust where planets and stars are born.“I'm very excited because we're going to be seeing parts of the universe that we haven't seen bef ore,”said Ned Wright, a scientist who directs the WISE project.Since arriving in space,the WISE telescope has been circling the Earth,held by gravity in a polar orbit4(this means it crosses close to the north and south poles with each lap5).Its camera is pointed outward,away from the Earth,and WISE will snap a picture of a different part of the sky every 11 minutes.After six months it will have taken pictures across the entire sky.The pictures taken by WISE won't be like everyday digital photographs,however.WISE stands for“Wide-field Infrared Survey Explorer.”As its name suggests,the WISE camera takes pictures of features that give off infrared radiation6.Radiation is energy that travels as a wave.Visible light, including the familiar spectrum of light7 that becomes visible in a rainbow,is an example of radiation.When an ordinary digital camera takes a picture of a tree,for example,it receives the waves of visible light that are reflected off the tree.When these waves enter the camera through the lens,they're processed by the camera,which then puts the image together.Waves of infraredradiation are longer than waves of visible light, so ordinary digital cameras don't see them,and neither do the eyes of human beings.Although invisible to the eye,longer infrared radiation can be detected as warmth by the skin.That's a key idea to why WISE will be able to see things other telescopes can't.Not everything in the universe shows up in visible light.Asteroids,for example,are giant rocks that float through space 一but they absorb most of the light that reaches them.They don't reflect light,so they're difficult to see.But they do give off infrared radiation, so an infrared telescope like WISE will be able to produce images of them.During its mission WISE will take pictures of hundreds of thousands of asteroids.Brown dwarfs8 are another kind of deep-space object that will show up in WISE's pictures.These objects are“failed” stars 一which means they are not massive enough to jump start9 the same kind of reactions that power stars such as the sun.Instead,brown dwarfs simply shrink and cool down.They're so dim that they're almost impossible to see with visible light, but in the infrared spectrum they glow.词汇：trashcan / 'træʃ,kæn/n．垃圾箱 infrared/'infrə'red/ adj．红外线asteroid/'æstərɔid/ n.小行星 dwarf/dwɔ:f/ n.矮星注释：1.NASA（美国国家航空航天局）是缩写词，全称是National Aeronautics and Space Administration2.the wildest objects ：任何你能想象得到的天体。
考研英语阅读综合辅导——动物学类
阅读综合辅导[动物学类]题⽬序号题型归类第1题中⼼主旨题型第2题归纳推导题型第3题审题定位题型第4题主题句理解题型第5题句间关系题型 Investigators of monkey’s social behavior have always been struck by monkeys’ aggressive potential and the consequent need for social control of their aggressive behavior. Studies directed at describing aggressive behavior and the situations that elicit it, as well as the social mechanisms that control it, were therefore among the first investigations of monkeys’ social behavior. Investigators initially believed that monkeys would compete for any resource in the environment: hungry monkeys would fight over food, thirsty monkeys would fight over water, and, in general, at time more than one monkey in a group sought the same incentive simultaneously, a dispute would result and would be resolved through some form of aggression. However, the motivating force of competition for incentives began to be doubted when experiments like Southwick’s on the reduction of space or the withholding of food failed to produce more than temporary increases in intragroup aggression. Indeed, food deprivation not only failed to increase aggression but in some cases actually resulted in decreased frequencies of aggression. Studies of animals in the wild under conditions of extreme food deprivation likewise revealed that starving monkeys devoted almost all available energy to foraging, with little energy remaining for aggressive interaction. Furthermore, accumulating evidence from later studies of a variety of primate groups, for example, the study conducted by Bernstein, indicates that one of the most potent stimuli for eliciting aggression is the introduction of an intruder into an organized group. Such introductions result in far more serious aggression than that produced in any other types of experiments contrived to produce competition. These studies of intruders suggest that adult members of the same species introduced to one another for the first time show considerable hostility because, in the absence of a social order, one must be established to control interanimal relationships. When a single new animal is introduced into an existing social organization, the newcomer meets even more serious aggression. Whereas in the first case aggression establishes a social order, in the second case resident animals mob the intruder, thereby initially excluding the new animal from the existing social unit. The simultaneous introduction of several animals lessens the effect, if only because the group divides its attention among the multiple targets. If, however, the several animals introduced a group constitute their own social unit, each group may fight the opposing group as a unit; but, again, no individual is subjected to mass attack, and the very cohesion of the groups precludes prolonged individual combat. The submission of the defeated group, rather than unleashing unchecked aggression on the part of the victorious group, reduces both the intensity and frequency of further attack. Monkey groups therefore seem to be organized primarily to maintain their established social order rather than to engage in hostilities per se. 1.The author of the text is primarily concerned with [A] advancing a new methodology for changing a monkey’s social behavior. [B] comparing the methods of several research studies on aggression among monkeys. [C] explaining the reasons for researcher’s interest in monkey’s social behavior. [D] discussing the development of investigators’ theories about aggression among monkeys. 2.Which of the following best summarizes the findings reported in the text about the effects of food deprivation on monkeys’ behavior? [A] Food deprivation has no effect on aggression among monkeys. [B] Food deprivation increases aggression among monkeys because one of the most potent stimuli for eliciting aggression is the competition for incentives. [C] Food deprivation may increase long-term aggression among monkeys in a laboratory setting, but it produces only temporary increase among monkeys in the wild. [D] Food deprivation may temporarily increase aggression among monkeys, but it also leads to a decrease in conflict. 3.The text suggests that investigators of monkeys’ social behavior have been especially interested in aggressive behavior among monkeys because [A] aggression is the most common social behavior among monkeys. [B] successful competition for incentives determines the social order in a monkey group. [C] situation that elicit aggressive behavior can be studied in a laboratory. [D] most monkeys are potentially aggressive, yet they live in social units that could not function without control of their aggressive impulses. 4.The text supplies information to answer which of the following questions? [A] How does the reduction of space affect intragroup aggression among monkeys in an experimental setting? [B] Do family units within a monkey social group compete with other family units for food? [C] What are the mechanisms by which the social order of an established group of monkeys controls aggression within that group? [D] How do monkeys engaged in aggression with other monkeys signal submission? 5.Which of the following best describes the organization of the second paragraph? [A] A hypothesis is explained and counter evidence is described. [B] A theory is advanced and specific evidence supporting it is cited. [C] Field observations are described and a conclusion about their significance is drawn. [D] Two theories are explained and evidence supporting each of them is detailed. [答案与考点解析] 1.【答案】D 【考点解析】本题是⼀道中⼼主旨题。
A point of view on the species concept
TAXON VOLUME 41
A point of view on the species concept Hans P. Nooteboom' The species concept is a subject of eternal discussion. My experience with very narrow species concepts held by some botanists, especially, but by no means exclusively, in China, prompts me to express my opinion, especially because in taxa with which I am familiar myself some other botanists, without studying the whole genus or family at least throughout its entire Old World area, hold a very narrow, and in my opinion unrealistic, species concept. A botanist should always keep two things in mind: (1) that he or she deals with populations that form biological species, and are likely to be variable, not only within populations of free interbreeding individuals, but even more between populations with possibly varying ecological amplitudes; and (2) that his or her work, while it may reflect the natural variability in the descriptions and notes, and sometimes through the recognition of subordinate taxa, has to be used by field botanists and plant taxonomists. It must be possible for the vast majority of newly found collections to be identified by means of the provided keys not only by the specialist but also by other people. Now, what is a species? The biological species concept implies that it consists of all populations of which the individuals are capable of interbreeding.A good example is Homo sapiens. The populations are spred over nearly the entire world and differ in a multitude of characters. Nevertheless, nobody nowadays doubts that Homo sapiens constitutes one species. It is easy to find parallel examples in plants, for which several botanists will argue:populations that are so different and live so far apart must belong to different species. Of course, it is difficult to prove that individuals of different populations are interfertile. It is always necessary to study as many collections as possible from numerous herbaria, not only for a restrictedarea but for the whole area where a taxon may occur. I know of botanists, working for a Flora, who did not even care to consult an important herbarium, holding many collections of their taxa, in their own city of residence. It may be evident that, scientifically, I do not consider this to be good practice, and the result might well be an unrealistically narrow species concept. The narrow species concept held by many botanists in the 19th and in the first half of the 20th century was often due to the fact that only few collections were available to them, so that they could not adequately study the variability of the species. Also, some were convinced that many species were endemic in a certain area (e.g. the Philippines: Merrill) and could not be found elsewhere. It is an established fact howeverthat some species are wide-spread and may even have a world-wide distribution, like Carex echinata Murray and Carex curta Gooden. A worldwide distribution is not an exclusive privilege of mankind! Earlier botanists would have adopted a much wider species concept, had they had at their disposal as many collections as we presently have (or can have).
tpo40三篇托福阅读TOEFL原文译文题目答案译文背景知识
tpo40三篇托福阅读TOEFL原文译文题目答案译文背景知识阅读-1 (2)原文 (2)译文 (5)题目 (8)答案 (17)背景知识 (17)阅读-2 (20)原文 (20)译文 (23)题目 (25)答案 (35)背景知识 (35)阅读-3 (38)原文 (38)译文 (41)题目 (44)答案 (53)背景知识 (54)阅读-1原文Ancient Athens①One of the most important changes in Greece during the period from 800 B.C. to 500 B.C. was the rise of the polis, or city-state, and each polis developed a system of government that was appropriate to its circumstances. The problems that were faced and solved in Athens were the sharing of political power between the established aristocracy and the emerging other classes, and the adjustment of aristocratic ways of life to the ways of life of the new polis. It was the harmonious blending of all of these elements that was to produce the classical culture of Athens.②Entering the polis age, Athens had the traditional institutions of other Greek protodemocratic states: an assembly of adult males, an aristocratic council, and annually elected officials. Within this traditional framework the Athenians, between 600 B.C. and 450 B.C., evolved what Greeks regarded as a fully fledged democratic constitution, though the right to vote was given to fewer groups of people than is seen in modern times.③The first steps toward change were taken by Solon in 594 B.C., when he broke the aristocracy's stranglehold on elected offices by establishing wealth rather than birth as the basis of office holding, abolishing the economic obligations of ordinary Athenians to the aristocracy, and allowing the assembly (of which all citizens were equal members) to overrule the decisions of local courts in certain cases. The strength of the Athenian aristocracy was further weakened during the rest of the century by the rise of a type of government known as a tyranny, which is a form of interim rule by a popular strongman (not rule by a ruthless dictator as the modern use of the term suggests to us). The Peisistratids, as the succession of tyrants were called (after the founder of the dynasty, Peisistratos), strengthened Athenian central administration at the expense of the aristocracy by appointing judges throughout the region, producing Athens’ first national coinage, and adding and embellishing festivals that tended to focus attention on Athens rather than on local villages of the surrounding region. By the end of the century, the time was ripe for more change: the tyrants were driven out, and in 508 B.C. a new reformer, Cleisthenes, gave final form to the developments reducing aristocratic control already under way.④Cleisthenes' principal contribution to the creation of democracy at Athens was to complete the long process of weakening family and clanstructures, especially among the aristocrats, and to set in their place locality-based corporations called demes, which became the point of entry for all civic and most religious life in Athens. Out of the demes were created 10 artificial tribes of roughly equal population. From the demes, by either election or selection, came 500 members of a new council, 6,000 jurors for the courts, 10 generals, and hundreds of commissioners. The assembly was sovereign in all matters but in practice delegated its power to subordinate bodies such as the council, which prepared the agenda for the meetings of the assembly, and courts, which took care of most judicial matters. Various committees acted as an executive branch, implementing policies of the assembly and supervising, for instance, the food and water supplies and public buildings. This wide-scale participation by the citizenry in the government distinguished the democratic form of the Athenian polis from other less liberal forms.⑤The effect of Cleisthenes’ reforms was to establish the superiority of the Athenian community as a whole over local institutions without destroying them. National politics rather than local or deme politics became the focal point. At the same time, entry into national politics began at the deme level and gave local loyalty a new focus: Athens itself. Over the next two centuries the implications of Cleisthenes’ reforms were fully exploited.⑥During the fifth century B.C. the council of 500 was extremely influential in shaping policy. In the next century, however, it was the mature assembly that took on decision-making responsibility. By any measure other than that of the aristocrats, who had been upstaged by the supposedly inferior "people", the Athenian democracy was a stunning success. Never before, or since, have so many people been involved in the serious business of self-governance. It was precisely this opportunity to participate in public life that provided a stimulus for the brilliant unfolding of classical Greek culture.译文古雅典①在公元前800年到公元前500年期间，希腊最重要的变化之一是城邦的崛起，并且每个城邦都发展了适合其情况的政府体系。
写昆虫的英语作文
Insects are a class of creatures that have fascinated humans for centuries due to their incredible diversity,unique behaviors,and vital roles in ecosystems.Here is an English essay about insects,exploring their characteristics,importance,and some of the most common species.The Marvel of Insects:A World of Tiny GiantsInsects are the most diverse group of animals on our planet,with over a million described species and many more yet to be discovered.They belong to the class Insecta within the phylum Arthropoda,characterized by a chitinous exoskeleton,a threepart body head, thorax,and abdomen,three pairs of jointed legs,compound eyes,and one pair of antennae.Characteristics of Insects1.Exoskeleton:Insects possess a hard,protective exoskeleton made of chitin,which provides structural support and protection from predators and environmental factors.2.Metamorphosis:Many insects undergo metamorphosis,a process of development that includes four distinct life stages:egg,larva,pupa,and adult.This allows for drastic changes in form and function as they grow.3.Reproduction:Insects reproduce at an astonishing rate,with many species laying hundreds or even thousands of eggs at a time,ensuring the survival of their species.4.Diversity:Insects are incredibly diverse in size,shape,and color,ranging from the tiny fairyfly to the large,colorful butterflies and beetles.Importance of Insects1.Pollination:Many insects,particularly bees,butterflies,and moths,play a crucial role in pollinating plants,which is essential for the production of fruits,vegetables,and nuts.2.Decomposition:Insects such as beetles and flies are vital in breaking down dead organic matter,recycling nutrients back into the ecosystem.3.Food Source:Insects are a primary food source for many animals,including birds, reptiles,and other insects.4.Biological Control:Some insects,like ladybugs and praying mantises,are natural predators of pests,helping to control populations of harmful insects in agriculture.Common Insect Species1.Butterflies and Moths Lepidoptera:Known for their beautiful wings and patterns,they are important pollinators and serve as a food source for many animals.2.Beetles Coleoptera:With the largest number of species,beetles are incredibly diverse, from the small ladybugs to the large,shiny scarabs.3.Ants,Bees,and Wasps Hymenoptera:These social insects are known for their complex colonies and roles in pollination and pest control.4.Flies Diptera:Although many species are considered pests,some,like the hoverfly,are beneficial pollinators.5.Dragonflies and Damselflies Odonata:These agile fliers are predators of other insects and are important for controlling mosquito populations.Conservation and InsectsInsects face numerous threats,including habitat loss,pesticide use,and climate change.It is crucial to protect their habitats and reduce the use of harmful chemicals to ensure the survival of these essential creatures.ConclusionInsects are not just a part of nature they are the backbone of many ecosystems.Their survival is intertwined with ours,and understanding their importance can lead to better stewardship of our environment.As we continue to explore the world of insects,we uncover the intricate connections that bind us all in the web of life.This essay provides a comprehensive overview of insects,their characteristics,ecological importance,common species,and the need for conservation efforts.It is a testament to the significance of these tiny creatures in the grand scheme of life on Earth.。
11.8号托福阅读真题答案解析
11.8号托福阅读真题答案解析本文关于2017年11月18日阅读真题回忆，有利于考生备考复习。
让我们回忆一下最近考试的内容：环境类，生物类，词汇题等，请考生们要认真的阅读哦，来店铺会给你不一样的精彩内容，店铺会在考试后第一时间更新。
11.8号托福阅读答案解析阅读部分考试回忆如下：1. Preventing Overgrowth among Tree Branchesshedding剪枝的意义。
一个是因为有些树枝消耗掉的碳物质比生产的多，另一个原因是有时候气候很干，剪枝减少水的消耗。
词汇题补充：exposed = unprotectedwith no warning = without any indication beforehandcongestion = overcrowding2. Crown of Thorns Starfish and Coral Reefs冠状棘海星，话题重复2011.01.08珊瑚的消失和一种海星的数量猛增有关系，主要说的是导致猛增的原因(环境+人)词汇题补充：outbreak = sudden increaseaccompany = occur along withconverge = come togetherseverity = seriousness原题重现：The crown of thorns starfish, Acanthaster Tlanci, is large, twenty-five to thirty-five centimeters in diameter, and has seven to twenty-one arms that are covered in spines. It feeds primarily on coral and is found from the Indian Ocean to the west coast of Central America, usually at quite low population densities. Sincethe mid-1950s, population outbreaks at densities four to six times greater than normal have occurred at the same time in places such as Hawaii, Tahiti, Panama, and the Great Barrier Reef. The result has often been the loss of a fifty percent to nearly one hundred percent of the coral cover over large areas.A single Acanthaster can consume five to six square meters of coral polyps per year, and dense populations can destroy up to six square kilometers per year and move on rapidly. Acanthasters show a preference for branching corals, especially Acroporids. After an outbreak in a particular area, it is common to find that Acroporids have been selectively removed, leaving a mosaic of living and dead corals. In places where Acroporids previously dominated the community devastation can be almost complete, and local areas of reefs have collapsed.Areas of dead coral are usually colonized rapidly by algae and often are later colonized by sponges and soft corals. Increases in abundance of plant-eating fish and decreases in abundance of coral-feeding fish accompany these changes. Coral larvae settle among the algae and eventually establish flourishing coral colonies. In ten to fifteen years the reefs often return to about the same percentage of coral cover as before. Development of a four-species diversity takes about twenty years.Two schools of thought exist concerning the cause of these outbreaks. One group holds that they are natural phenomena that have occurred many times in the past, citing old men's recollections of earlier outbreaks and evidence from traditional cultures. The other group maintains that recent human activities ranging from physical coral destruction through pollution to predator removal have triggered these events.One theory, the adult aggregation hypothesis, maintains thatmost species is more abundant than we realize when a storm destroys coral and causes a food shortage. The adult Acanthasters converge on remaining portions of healthy coral and feed hungrily. Certainly there have been outbreaks of Acanthaster following large storms, but there is little evidence that the storms have caused the enough reef damage to create a food shortage for these starfish.Two other hypotheses attempt to explain the increased abundance of Acanthaster after episodes of high terrestrial runoff following storms. The first hypothesis is that low salinity and high temperatures favor the survival of the starfish larvae. The second hypothesis emphasizes the food web aspect, suggesting that strong fresh water runoff brings additional nutrients to the coastal waters, stimulating phytoplankton production and promoting more rapid development and better survival of the starfish larvae.Those favoring anthropogenic (human influenced) causes have pointed to the large proportion of outbreaks that have been near centers of human populations. It has been suggested that coral polyps are the main predators of the starfish larvae. Destruction of coral by blasting and other bad land use practices would reduce predation on the starfish larvae and cause a feedback in which increases in Acanthaster populations cause still further coral destruction. Unfortunately, there are too few documented instances of physical destruction of coral being followed by outbreaks of Acanthaster for these hypotheses to be fully supported.Another group of hypothesis focuses on removal of Acanthaster's predators. Some have suggested that the predators might have been killed off by pollution whereas othershave suggested that the harvesting of vertebrate and invertebrate predators of Acanthaster could have reduced mortality and caused increased abundance of adults. The problem with this group of hypothesis is that it is difficult to understand how reduced predation would lead to sudden increases in Acanthaster numbers in several places at the same time in specific years. It seems probable that there is no single explanation but that there are elements of the truth in several of the hypotheses. That is there are natural processes that have led to outbreaks in the past, but human impact has increased the frequency and severity of the outbreaks.3.Dorset Culture格林兰岛Dorset Culture的起源，首先是由于气候变冷，一部分人迁走了，另一部分留下来的人创立了文明。
2014-06-21Reading(气候变化和N人-没做出答案-最后一篇有小瑕疵)
Climate Change and the Natufian PeopleThe so-called Natufian culture inhabited what is now the Middle East between approximately 14,000 and 11,500 years ago. This period is commonly split into two subperiods, Early Natufian (14,000 to 13,000 years ago) and Late Natufian (13,000 to 11,500). The Natufians were hunter-gatherers who relied primarily on gazelle, although they also cultivated some cereal grains. During the early period at least, they lived year-round in villages in built stone houses. Like all human beings, their way of life depended on the climate. Around 13,000 years ago, their climate began to change, becoming colder and drier, a period known as the Younger Dryas.We know that times were hard in the increasingly arid landscapes of the Younger Dryas, but quite how hard remains unclear. The droughts certainly caused many ponds and rivers to disappear completely and the larger lakes to shrink in size. The people who lived in the south, in today’s deserts of the Negev and the Sinai, were most likely hit the hardest. They returned to a completely transient hunter-gatherer way of life, moving from place to place. Survival required improved hunting weapons: game (animals hunted for food) had become scarce, and consequently, success had become essential when a kill was possible. And so we see the invention of the Harif point, a new kind of arrowhead.Further north, the impact of the Younger Dryas may have been less severe. Yet survival still required more than just a return to the ancient mobile hunter-gatherer lifestyle, especially as there were now many more people needing food than had been the case during earlier periods, when the Natufians lived in permanent dwellings. One response was to hunt a much wider range of animals than before, and hence we find in Late Natufian settlements the bones of many small-game species as well as larger, ever-present gazelle.Another response to the changing climate was to continue, and perhaps expand the cultivation of plants. Wild cereals were particularly hard hit by the Younger Dryas owing to a decrease in the concentration of carbon dioxide (CO2) in the atmosphere. This diminution, carefully documented from air bubbles trapped in Antarctic ice, inhibited their photosynthesis and markedly reduced their yields. Consequently, whatever cultivation practices had begun during the Early Natufian period—weeding, transplanting, watering, pest control—may now have become essential to secure sufficient food. And these may have created the first domesticated strains.This appears to be what happened at the village of Abu Hureyra just before its abandonment. When the archaeologist Gordon Hillman studied the cereal grains from the site, he found a few grains of rye from plants that had undergone the transition into domestic forms. When dated, they were shown to lie between 11,000 and 10,500 B.C.—the oldest domesticated cereal grain from anywhere in the world. Along with these grains, Hillman found seeds from the weeds that typically grow in cultivated soil. And so it appears that, as the availability of wild plant foods declined due to the onset of the Younger Dryas, the Abu Hureyra people invested an ever greater amount of time and effort in caring for the wild rye and by doing so unintentionally transformed it into a domestic crop. But even this could not support the village—it was abandoned as people were forced to return to a mobile lifestyle, perhaps carrying pouches of cereal grain. Thedomesticated rye of Abu Hureyra reverted to its wild state.The geographical range of the Late Natufians also changed. With their increased interest in plant cultivation, the Late Natufians drifted away from the depleted woodlands where their forebears once flourished. They were drawn to the alluvial soils (soils deposited by rivers) of the valleys, not only those of the River Jordan, but also those found by the great rivers of the Mesopotamian plain and in the vicinity of lakes and rivers throughout the Middle East. Large expanses of these rich, fertile soils became available as the rivers and lakes struck during the Younger Dryas Wild, but cultivated, cereals grew well in such soil, especially when close to the meager springs, ponds, and streams that survived the arid conditions.Paragraph 2We know that times were hard in the increasingly arid landscapes of the Younger Dryas, but quite how hard remains unclear. The droughts certainly caused many ponds and rivers to disappear completely and the larger lakes to shrink in size. The people who lived in the south, in today’s deserts of the Negev and the Sinai, were most likely hit the hardest. They returned to a completely transient hunter-gatherer way of life, moving from place to place. Survival required improved hunting weapons: game (animals hunted for food) had become scarce, and consequently, success had become essential when a kill was possible. And so we see the invention of the Harif point, a new kind of arrowhead.1.Which of the following can be inferred from paragraph 2 about why game became scarceduring the Younger Dryas?The development of new weapons in the south improved the Natufians’ hunting successes. Human settlement in the south destroyed the resources that allowed game animals to survive.Animals died or moved away as their sources of drinking water dried up.Animals were scared away by the Natufians’ rapid movement from place to place. Paragraph 2 is marked with an arrow [→]2.In paragraph 2, why does the author mention the Harif point?To support the idea that the Younger Dryas required Natufians to hunt in new waysTo illustrate how humans had begun to protect their settlements during the Younger Dryas To contrast the settled lifestyle of villages with the transient lifestyle of hunter-gathersTo explain the process by which ancient people invented arrowheadsParagraph 3Further north, the impact of the Younger Dryas may have been less severe. Yet survival still required more than just a return to the ancient mobile hunter-gatherer lifestyle, especially as there were now many more people needing food than had been the case during earlier periods, when the Natufians lived in permanent dwellings. One response was to hunt a much wider range of animals than before, and hence we find in Late Natufian settlements the bones of many small-game species as well as larger, ever-present gazelle.3.According to paragraph 3, what did the Natufians do to feed their increasing populationduring the Younger Dryas?They began to trade food products with other people in neighboring areas.They began hunting a wider range of animals.They tried to hunt mostly the larger animals.They moved south where there were more animals.Paragraph 3 is marked with an arrow [→]Paragraph 4Another response to the changing climate was to continue, and perhaps expand the cultivation of plants. Wild cereals were particularly hard hit by the Younger Dryas owing to a decrease in the concentration of carbon dioxide (CO2) in the atmosphere. This diminution, carefully documented from air bubbles trapped in Antarctic ice, inhibited their photosynthesis and markedly reduced their yields. Consequently, whatever cultivation practices had begun during the Early Natufian period—weeding, transplanting, watering, pest control—may now have become essential to secure sufficient food. And these may have created the first domesticated strains.4.According to paragraph 4, air bubbles in Antarctic ice are evidence of which of the followingduring the Younger Dryas period?Areduction in atmospheric carbon dioxideAn increase in the number of weedsImprovements in cultivation of plantsGreater use of pest controlsParagraph 4 is marked with an arrow [→]5.The word “inhibited” in the passage is closet in meaning toalteredrequiredrestrictedallowed6.The word “sufficient” in the passage is closet in meaning toenoughfreshvaluablenutritiousParagraph 5This appears to be what happened at the village of Abu Hureyra just before its abandonment. When the archaeologist Gordon Hillman studied the cereal grains from the site, he found a few grains of rye from plants that had undergone the transition into domestic forms. When dated, they were shown to lie between 11,000 and 10,500 B.C.—the oldest domesticated cereal grain from anywhere in the world. Along with these grains, Hillman found seeds from the weeds that typically grow in cultivated soil. And so it appears that, as the availability of wild plant foodsdeclined due to the onset of the Younger Dryas, the Abu Hureyra people invested an ever greater amount of time and effort in caring for the wild rye and by doing so unintentionally transformed it into a domestic crop. But even this could not support the village—it was abandoned as people were forced to return to a mobile lifestyle, perhaps carrying pouches of cereal grain. The domesticated rye of Abu Hureyra reverted to its wild state.7.In paragraph 5, why does the author described the archaeologist’s findings at Abu Hureyra? To identify the best-known Natufian villageTo question the idea that wild grains were first domesticated more than 11,000 years agoTo challenge the idea presented in paragraph 4 that earlier cultivation practices became essential for Natufian survival during the Younger DryasTo provide evidence supporting the theory presented in paragraph 4 about how wild plants became domesticatedParagraph 5 is marked with an arrow [→]8.According to paragraph 5, what was one response of the people of Abu Hureyra to the onsetof the Younger Dryas?They began collecting a wider variety of wild grains.They began cultivating crops at sites outside Abu Hureyra.They developed special pouches for storing and carrying cereal grain.They spent more energy and time cultivating their rye crop.Paragraph 5 is marked with an arrow [→]9.According to paragraph 5, what happened to the domesticated rye left at Abu Hureyra?It developed a number of different strains.It became wild again.It became extinct.It could no longer be used as food.Paragraph 5 is marked with an arrow [→]Paragraph 6The geographical range of the Late Natufians also changed. With their increased interest in plant cultivation, the Late Natufians drifted away from the depleted woodlands where their forebears once flourished. They were drawn to the alluvial soils (soils deposited by rivers) of the valleys, not only those of the River Jordan, but also those found by the great rivers of the Mesopotamian plain and in the vicinity of lakes and rivers throughout the Middle East. Large expanses of these rich, fertile soils became available as the rivers and lakes struck during the Younger Dryas Wild, but cultivated, cereals grew well in such soil, especially when close to the meager springs, ponds, and streams that survived the arid conditions.10.The word “flourished” in the passage is closet in meaning tosettledstruggledgatheredprospered11.The phrase “drawn to” in the passage is closet in meaning toconcerned byattracted towardimpressed bysurrounded by12.According to paragraph 6, why did the Natufians move to river valleys during the YoungerDryas?Plants grew better in the fertile soil next to bodies of water.The Natufians followed the game animals there.The Natufians used the rivers as their means of transportation.The valleys had more woodlands, which the Natufians needed for home building. Paragraph 6 is marked with an arrow [→]Paragraphs1 and 2The so-called Natufian culture inhabited what is now the Middle East between approximately 14,000 and 11,500 years ago. This period is commonly split into two subperiods, Early Natufian (14,000 to 13,000 years ago) and Late Natufian (13,000 to 11,500). The Natufians were hunter-gatherers who relied primarily on gazelle, although they also cultivated some cereal grains. ■During the early period at least, they lived year-round in villages in built stone houses. Like all human beings, their way of life depended on the climate. ■Around 13,000 years ago, their climate began to change, becoming colder and drier, a period known as the Younger Dryas.■We know that times were hard in the increasingly arid landscapes of the Younger Dryas, but quite how hard remains unclear. ■The droughts certainly caused many ponds and rivers to disappear completely and the larger lakes to shrink in size. The people who lived in the south, in today’s deserts of the Negev and the Sinai, were most likely hit the hardest. They returned to a completely transient hunter-gatherer way of life, moving from place to place. Survival required improved hunting weapons: game (animals hunted for food) had become scarce, and consequently, success had become essential when a kill was possible. And so we see the invention of the Harif point, a new kind of arrowhead.13.Look at the four squares [■] that indicate where the following sentence could be added tothe passage.As long as the climate remained moderate, the Natufians were able to thrive by remaining in their villages.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 mostimportant ideas in the passage. Some answer choices do not belong in the summary because they express ideas that are not 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.Answer ChoicesAs lakes and rivers dried up, Natufiansabandoned their settlements in some areas and became mobile hunters, developing new, more efficient hunting weapons to improve their success in the hunt.Cereal yields dropped when the air became excessively concentrated with carbon dioxide, which impaired photosynthesis.In one Natufian village, an archaeologist found the oldest-known domesticated cereal grain, dating from more than 14,000 years ago. A major contribution of Natufian culture to early civilization was the invention of a new arrowhead called the Harif point.With wild grains no longer plentiful, the Natufians had to invent better cultivation techniques, resulting in new domesticated varieties.The climate change forced some Late Natufians to move away from their former woodland homes and inhabit the fertile lands left by the receding rivers and lakes.MetamorphosisOrganisms that metamorphose undergo radical changes over the course of their life cycle. A frog egg hatches a tadpole that metamorphoses into an adult frog within a few days or weeks. A fruit fly egg hatches a larva that feeds for a few hours or days and then enters the pupal stage during which it develops a protective covering. The changes that occur during the metamorphosis of a single species may be so great that the species occupies two separate and very different niches or places in an environment at different times. In fact, the larvae of two species may be more similar to each other than to the corresponding adult forms of their own species.Organisms that utilize different resources at different stages of their life cycle face an unusual evolutionary problem, exploiting different niches may be difficult with a single body plan. The solution is a juvenile (immature) form specialized for one niche, followed by metamorphosis to an entirely new body plan, adapted to a different niche in the adult. Clearly, species that metamorphose must undertake complex genetic and physiological processes in the transformation. These changes require complex regulatory mechanisms that involve turning on and off many genes at appropriate times. In addition, the reorganization of the body plan in a metamorphic species entails considerable energy costs. What sorts of ecological advantages could outweigh these complications?One prevailing hypothesis is that metamorphic species specialize so as to exploit habitats with high but transient (short term) productivity----and hence high potential for growth. Part of this strategy is that specializations for feeding, dispersal, and reproduction are separated across stages. A frog tadpole occupies an aquatic environment (such as a pond) with extremely high potential for growth. The existence of the pond or its high production may be transient, however. Whereas an aquatic larva is not capable of dispersal to new ponds if its habitat becomes unsuitable, the adult frog is. In this case rapid growth in the larva is separated from dispersal and reproduction in the adult. Although the adult feeds, its growth rate is far less than that of the tadpole. The energy adults obtain from feeding is dedicated to dispersal and reproduction.Many insects benefit from the same strategy. Although a butterfly larva feeds voraciously, often on a very specific set of host plant species, the adult does not grow. If it feeds, it does so only to maintain energy reserves required for dispersal and reproduction. The monarch butterfly exemplifies this strategy. Its larvae feed specifically on milkweeds. Monarch pupae also develop on this host plant. The emerging adults migrate long distances----from all over eastern North America to nine small sites in the Sierra Madre mountains of Mexico. There, females become sexually mature and migrate north, mating along the way and feeding only to maintain energy reserves. In this example, the feeding specialist stage is again separated from the dispersal and reproduction stages.In the previous examples, the reproductive function is delegated to the adult. Under certain ecological conditions, however, it is apparently advantageous for reproduction to occur in the larval stage. Thus, even the reproductive function typically fulfilled by the adult can apparently be modified under certain circumstances. Species that show this modification of a metamorphic lifecycle are said to demonstrate neoteny, a life cycle in which the larvae of some populations or races become sexually mature and no longer metamorphose into adult. Some populations of the salamander Ambystoma maculatum show this trait. In fact, the larvae of this species were originally classified as a separate species before it was recognized that they are neotenic forms.The selective factors leading to neoteny are not well understood. We know, however, that neotenicforms are more frequently found in extreme environments, often high altitudes or latitudes. High-altitude populations of certain salamanders have higher frequencies of neoteny than do low-elevation population of these species. If the larval environment is rich compared to the harsh adult environment, selection may favor neoteny. One research study, has ruled out simple food effects, supplemental food did not increase the frequency with which organisms reached the adult stage. This suggests that neoteny may be a genetically determined feature of some amphibian life histories.Paragraph 1Organisms that metamorphose undergo radical changes over the course of their life cycle. A frog egg hatches a tadpole that metamorphoses into an adult frog within a few days or weeks. A fruit fly egg hatches a larva that feeds for a few hours or days and then enters the pupal stage during which it develops a protective covering. The changes that occur during the metamorphosis of a single species may be so great that the species occupies two separate and very different niches or places in an environment at different times. In fact, the larvae of two species may be more similar to each other than to the corresponding adult forms of their own species.1.The word “radical” in the passage is closest in meaning toextremedistinctiveperiodicstructural2.According to paragraph 1, which of the following is true of the organisms that become fruitflies?They feed during the pupal stage.They become winged insects several days after the larvae hatch from eggs.They remain in the larval stage longer than they remain in the pupal stage.They need to be protected during the larval stage in order to reach the pupal stage.Paragraph 2Organisms that utilize different resources at different stages of their life cycle face an unusual evolutionary problem, exploiting different niches may be difficult with a single body plan. The solution is a juvenile (immature) form specialized for one niche, followed by metamorphosis to an entirely new body plan, adapted to a different niche in the adult. Clearly, species that metamorphose must undertake complex genetic and physiological processes in the transformation. These changes require complex regulatory mechanisms that involve turning onand off many genes at appropriate times. In addition, the reorganization of the body plan in a metamorphic species entails considerable energy costs. What sorts of ecological advantages could outweigh these complications?3.It can be inferred from paragraph 2 that an advantage ofdevelop regulatory mechanisms for turning genes on and offoccupy different niches at different parts of the life cycleundertake complex genetic and physiological processesreduce their energy costs4.Why does the author ask the question “What sorts of ecological advantages could outweighthese complications?”To suggest that there is no single advantage but many advantagesTo challenge the idea that metamorphic transformations are always beneficialTo prepare readers for a discussion that may explain why metamorphosis occursTo identify a particular aspect of metamorphosis that is poorly understoodParagraph 3One prevailing hypothesis is that metamorphic species specialize so as to exploit habitats with high but transient (short term) productivity----and hence high potential for growth. Part of this strategy is that specializations for feeding, dispersal, and reproduction are separated across stages. A frog tadpole occupies an aquatic environment (such as a pond) with extremely high potential for growth. The existence of the pond or its high production may be transient, however. Whereas an aquatic larva is not capable of dispersal to new ponds if its habitat becomes unsuitable, the adult frog is. In this case rapid growth in the larva is separated from dispersal and reproduction in the adult. Although the adult feeds, its growth rate is far less than that of the tadpole. The energy adults obtain from feeding is dedicated to dispersal and reproduction.5.The word “exploit” in the passage is closest in meaning toidentifyadapt touse to advantagebecome established in6.According to paragraph 3, by changing from a tadpole into an adult frog, an adult frog is abletomaintain a high growth rateprovide a safer habitat for its offspringobtain more foodmove to a more suitable locationParagraph 4Many insects benefit from the same strategy. Although a butterfly larva feeds voraciously, often on a very specific set of host plant species, the adult does not grow. If it feeds, it does so only to maintain energy reserves required for dispersal and reproduction. The monarch butterflyexemplifies this strategy. Its larvae feed specifically on milkweeds. Monarch pupae also develop on this host plant. The emerging adults migrate long distances----from all over eastern North America to nine small sites in the Sierra Madre mountains of Mexico. There, females become sexually mature and migrate north, mating along the way and feeding only to maintain energy reserves. In this example, the feeding specialist stage is again separated from the dispersal and reproduction stages.7.According to paragraph 3 and 4, what do frogs and butterflies have in common?Adults of both reproduce only when there is enough food in a habitat to sustain their offspring.Adults of both eat only enough to supply the energy needed for dispersal and reproduction.Immature forms of both disperse to new habitats when the habitats they are in can no longer sustain them.Immature forms of both depend on aquatic environments.8.The phrase “the same strategy” in the passage refers todispersing to new habitats as adultsspending most of the life cycle on dispersal and reproductionfeeding on a specific set of host plant speciesseparating specialization for feeding from dispersal and reproductionParagraph 5In the previous examples, the reproductive function is delegated to the adult. Under certain ecological conditions, however, it is apparently advantageous for reproduction to occur in the larval stage. Thus, even the reproductive function typically fulfilled by the adult can apparently be modified under certain circumstances. Species that show this modification of a metamorphic life cycle are said to demonstrate neoteny, a life cycle in which the larvae of some populations or races become sexually mature and no longer metamorphose into adult. Some populations of the salamander Ambystoma maculatum show this trait. In fact, the larvae of this species were originally classified as a separate species before it was recognized that they are neotenicforms.9.The word “apparently” in the passage is closest in meaning tousuallyespeciallyseeminglycertainly10.According to paragraph 5, why were the larvae of some populations of the salamanderspecies Ambystoma maculatum once thought to be members of a separate species?Because they were shaped differently than other larvae of Ambystoma maculatum.Because they were discovered far away from other members of Ambystoma maculatum.Because they were sexually mature and could reproduce.Because the neotenic form of Ambystoma maculatum looks very different from theneotenic forms of other salamanders.Paragraph 6The selective factors leading to neoteny are not well understood. We know, however, that neotenicforms are more frequently found in extreme environments, often high altitudes or latitudes. High-altitude populations of certain salamanders have higher frequencies of neoteny than do low-elevation population of these species. If the larval environment is rich compared to the harsh adult environment, selection may favor neoteny. One research study, has ruled out simple food effects, supplemental food did not increase the frequency with which organisms reached the adult stage. This suggests that neoteny may be a genetically determined feature of some amphibian life histories.11.The word “harsh” in the passage is closest in meaning toseveretypicalrestrictedavailable12.Paragraph 6 indicates that greater frequency of neoteny in salamanders may be associatedwith all of the following EXCEPTan environment that is richer for larvae than for adultsan inadequate food supply for larvaea high-altitude locationa genetic makeup favoring neotenyParagraph 2Organisms that utilize different resources at different stages of their life cycle face an unusual evolutionary problem, exploiting different niches may be difficult with a single body plan. ■The solution is a juvenile (immature) form specialized for one niche, followed by metamorphosis to an entirely new body plan, adapted to a different niche in the adult. ■Clearly, species that metamorphose must undertake complex genetic and physiological processes in the transformation. ■These changes require complex regulatory mechanisms that involve turning on and off many genes at appropriate times. ■In addition, the reorganization of the body plan in a metamorphic species entails considerable energy costs. What sorts of ecological advantages could outweigh these complications?13.Look at the four squares [■] that indicate where the following sentence could be added tothe passage.Metamorphosis, however, comes with its own set of difficulties.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.。
濒临物种英文作文
濒临物种英文作文The endangered species are facing a critical situation. Their habitats are being destroyed at an alarming rate, and many of them are struggling to survive in the wild. It's a heartbreaking reality that we need to address urgently.The loss of biodiversity is a serious issue thataffects not only the endangered species themselves but also the entire ecosystem. When a species becomes extinct, it disrupts the delicate balance of nature and can have far-reaching consequences for other plants and animals.Conservation efforts are crucial in protecting endangered species. We need to work together to create and enforce laws that safeguard their habitats and prevent illegal hunting and poaching. Additionally, raising awareness about the plight of these species is essential in garnering support for their protection.Human activities, such as deforestation, pollution, andclimate change, are major contributors to the decline of endangered species. We must take responsibility for our actions and strive to minimize our impact on the environment to ensure the survival of these vulnerable creatures.The extinction of a species is irreversible, and once they are gone, they are gone forever. It's our moral obligation to do everything in our power to prevent this from happening and to ensure that future generations can continue to marvel at the beauty and diversity of the natural world.。
高二生物学与物种保护英语阅读理解30题
高二生物学与物种保护英语阅读理解30题1<背景文章>Coral reefs are one of the most diverse and beautiful ecosystems on Earth. They are often called the "rainforests of the sea" because of their high biodiversity. Corals are actually animals that live in colonies and build hard skeletons made of calcium carbonate. These skeletons form the structure of the reef.Coral reefs provide many important benefits. They protect coastlines from storms and erosion. They also provide habitats for thousands of species of fish, invertebrates, and plants. In addition, coral reefs are important for tourism and recreation.However, coral reefs are facing many threats. One of the biggest threats is climate change. Rising sea temperatures can cause coral bleaching, which is when corals expel the symbiotic algae that live inside them and turn white. This can lead to the death of the coral. Pollution, overfishing, and destructive fishing practices are also major threats to coral reefs.To protect coral reefs, many measures are being taken. Conservation organizations are working to raise awareness about the importance of coral reefs and to promote sustainable fishing practices. Governments are alsoimplementing regulations to reduce pollution and protect coral reefs. In addition, scientists are researching ways to restore damaged coral reefs.1. What are coral reefs often called?A. The deserts of the sea.B. The rainforests of the sea.C. The grasslands of the sea.D. The mountains of the sea.答案：B。
鲎的英语作文
In the vast tapestry of marine life, one creature stands out as a living fossil, a testament to evolutionary resilience, and an invaluable contributor to both ecological balance and human health: the horseshoe crab (Limulus polyphemus). This essay delves into the multifaceted nature of this remarkable species, exploring its unique biology, ecological significance, and the profound impact it has on modern medicine.I. Evolutionary Legacy and MorphologyThe horseshoe crab is a marine arthropod that has survived for over 450 million years, predating even the dinosaurs. Its iconic, helmet-shaped carapace, which gives rise to its common name, is but one of the many adaptations that have allowed this ancient creature to persist through multiple mass extinctions. The exoskeleton, composed of chitin and calcium carbonate, serves as a robust shield against predators and environmental pressures. The ten eyes, including two compound eyes, six simple eyes, and a pair of specialized eyes called median ocelli, enable the horseshoe crab to perceive both light intensity and polarization, crucial for navigation and mate detection.Underneath the carapace, the horseshoe crab possesses a segmented body with a unique circulatory system featuring blue, copper-based blood. This blood contains amebocytes, cells that play a pivotal role in the animal's immune response and, subsequently, in biomedical applications. The tail, or telson, is not a weapon but rather a balancing and steering mechanism used during swimming and righting oneself when flipped over.II. Ecological SignificanceHorseshoe crabs occupy a critical niche in coastal ecosystems, contributing to their overall health and stability in several ways.A. Benthic Ecosystem Engineers: Horseshoe crabs are deposit feeders, foraging primarily on benthic invertebrates such as worms, mollusks, and crustaceans. Their feeding activities help maintain sediment structure, nutrient cycling, and the composition of benthic communities. Moreover, their feces enrich the substrate with nutrients, fostering the growth ofmicroorganisms and supporting higher trophic levels.B. Breeding and Nesting: The annual spawning aggregations of horseshoe crabs are significant events in coastal ecosystems. These mass gatherings not only ensure genetic diversity but also provide a substantial food source for numerous shorebirds, such as the red knot, whose survival is tightly linked to the abundance of horseshoe crab eggs. The birds time their migrations to coincide with the spawning season, relying on this energy-rich food supply to fuel their long journeys.C. Habitat Provision: Horseshoe crab molts, discarded shells left behind as they grow, serve as shelters for various marine organisms like small fish, crabs, and snails, enhancing habitat complexity and biodiversity.III. Contributions to Human Health: The 'Blue Blood' MiracleBeyond their ecological importance, horseshoe crabs have made an indelible mark on modern medicine due to the unique properties of their blood. The amebocytes mentioned earlier contain a substance called Limulus amebocyte lysate (LAL), which coagulates in the presence of bacterial endotoxins, specifically lipopolysaccharides found in the cell walls of gram-negative bacteria. This clotting reaction forms the basis of the LAL test, a rapid and sensitive method for detecting contamination in medical equipment, pharmaceuticals, and intravenous drugs.The LAL test has revolutionized the healthcare industry by ensuring the sterility of countless medical products, thereby preventing potentially lethal infections in patients. It is estimated that over half of all intravenous drugs and medical devices in use today have undergone LAL testing. Moreover, the biomedical demand for horseshoe crab blood has generated a multimillion-dollar industry, creating economic opportunities while simultaneously highlighting the need for sustainable harvesting practices.IV. Conservation Challenges and Future PerspectivesDespite their ecological and biomedical significance, horseshoe crabs face numerous threats, including habitat loss, overharvesting for bait and biomedicalpurposes, and climate change-induced shifts in spawning patterns. These factors have led to population declines in some regions, raising concerns about the long-term viability of both the species and the ecosystem services they provide.To address these challenges, conservation efforts must focus on:A. Sustainable Harvesting: Implementing science-based harvest quotas, enforcing existing regulations, and promoting the use of alternative bait sources can help reduce fishing pressure on horseshoe crab populations. Additionally, the development of synthetic alternatives to LAL or methods to extract LAL without killing the animals could alleviate the strain on wild populations.B. Habitat Protection and Restoration: Preserving and restoring critical spawning habitats, such as sandy beaches and eelgrass beds, is essential for maintaining healthy horseshoe crab populations. This involves coordinating coastal zone management, mitigating pollution, and minimizing coastal development impacts.C. Research and Monitoring: Strengthening research programs to better understand horseshoe crab biology, ecology, and population dynamics is vital for informing effective conservation strategies. Regular monitoring of populations, coupled with the establishment of international databases and collaborative research networks, will enhance our ability to detect trends and respond to emerging threats.In conclusion, the horseshoe crab is a biological marvel that transcends its ancient origins. Its unique morphology, ecological significance, and unparalleled contributions to human health make it a flagship species for marine conservation. Recognizing and addressing the challenges facing horseshoe crabs is not only imperative for the preservation of this extraordinary creature but also for the continued wellbeing of coastal ecosystems and human society. By fostering a holistic approach to conservation that integrates scientific knowledge, sustainable practices, and public awareness, we can safeguard the future of this living fossil and the invaluable services it provides.。
人教版高中英语选择性必修第四册Unit 3 SectionⅠReading and Thinking
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UNIT 3 SEA EXPLORATION
英语（选择性必修·第四册 RJ ）
These turtles are found nesting along the coastline① of more than 80
countries, with the largest nesting populations found in Costa Rica and
move to waters along the coast where they find sea grass to eat. Adult green sea turtles face many threats，primarily from humans，
including injuries from boats，being caught in fishing nets and pollution.
Green Sea Turtles Green sea turtles are the world’s largest species of hard-shelled sea turtle. While most of them weigh about 136 to 181 kilograms， some can be as heavy as 204 kilograms.
Newly hatched sea turtles are also at risk of being hunted by animals such as birds，crabs，and raccoons as they move from their nests out to the sea.
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dig out a nest and lay about 115 eggs. Then she’ll cover the eggs with sand and return to the sea. After about two months，the babies will hatch from
托福阅读真题第16篇SpeciesCompetition
托福阅读真题第16篇SpeciesCompetitionInterspecific competition occurs when two or more species seek the same limited resource. In the 1930s, Russian biologist G.F. Gause devised a set of elegant laboratory experiments that provide the basis for our formal understanding of competition. Gause grew two different species of the single-celled Paramecium—P.aurelia and P. caudatum - -separately and together. Populations of both species always increased more rapidly when they were grown alone. When grown together, populations of both species grew more slowly. Eventually, P. aurelia totally displaced P. caudatum . The results of his experiments with Paramecium species, along with similar experiments he performed on other organisms, led Gause to form this postulate: two species that directly compete for essential resources cannot coexist; one species will eventually displace the other. This postulate has come to be known as the competitive exclusion principle.An acre of tropical forest may include over 100 species of trees, all of which depend on the same soil, water, and nutrients. Freshwater lakes may have dozens of species of fish, all of which feed on the planktonic algae and animals suspended in the water. Indeed, two or more species of Paramecium may be found in the same lake. These and many other examples from ecological communities in nature seem to contradict Gause's principle. If two competing species cannot coexist in the laboratory, how are they able to coexist in natural settings? This question has been the basis for hundreds of ecological studies.Ecologist G. Evelyn Hutchinson provided one of the most important explanations for the coexistence of competingorganisms. He proposed that each species has a fundamental niche , the complete range of environmental conditions, such as requirements for temperature, food, and water, over which the species might possibly exist. Hutchinson noted, however, that few species actually grow and reproduce in all parts of this theoretical range. Rather, species usually exist only where they are able to compete effectively against other species. Hutchinson used the term realized niche to describe the range of conditions where a species actually occurs given the constraints of competition. Species whose fundamental niches overlap significantly are potential competitors. Hutchinson suggested that these potential competitors are able to coexist because they divide up the fundamental niche. Hutchinson called this division of resources niche differentiation.Niche differentiation occurs among many different kinds of organisms. For example, five different species of warblers, small insect-eating birds, occur together in the evergreen forests of the United States. During nesting season, the primary food of all the warblers is caterpillars. Careful studies of the birds' feeding behavior reveal that each species competes most effectively in a different part of the forest's highest layer, and that is where each species can be found. The diverse grasses and herbs that grow in native prairies provide another example of niche differentiation. Above ground, these plants appear to be vying for the same space and resources. However, a careful mapping of root systems shows that different species are adapted to exploiting different portions of the soil. In addition, some species compete most effectively when growing in bright light, whereas others compete effectively when growing in the shade of taller plants.Some of Gause's experiments support Hutchinson's nichedifferentiation hypothesis. Under any specific set of conditions-the same temperature, water availability, food source, etc. Gause's principle holds true. But if conditions change, competition among species may produce different winners and losers. Indeed, if waste products are periodically removed, the outcome of the competition between P. aurelia and P. caudatum is reversed and P. caudatum wins. Thus, in a complex environment where waste materials are collected in some places and not in others, these two species could coexist.Time is required for one species to competitively displace another, and the competitive exclusion principle presumes that environmental conditions remain constant during that time. In nature, however, environments change from season to season and from year to year, SO conditions that are favorable to a particular species may not persist and environments that are constantly changing may allow competing species to coexist.1.Interspecific competition occurs when two or more species seek the same limited resource. In the 1930s, Russian biologist G.F. Gause devised a set of elegant laboratory experiments that provide the basis for our formal understanding of competition. Gause grew two different species of the single-celled Paramecium—P.aurelia and P. caudatum - -separately and together. Populations of both species always increased more rapidly when they were grown alone. When grown together, populations of both species grew more slowly. Eventually, P. aurelia totally displaced P. caudatum . The results of his experiments with Paramecium species, along with similar experiments he performed on other organisms, led Gause to form this postulate: two species that directly compete for essential resources cannot coexist; one species will eventuallydisplace the other. This postulate has come to be known as the competitive exclusion principle.。
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a r X i v :h e p -p h /9810508v 1 28 O c t 1998A conjecture on Centauro species ∗
M.J.Menon
Instituto de F´ısica “Gleb Wataghin ”
Universidade Estadual de Campinas,Unicamp
13083-970Campinas,SP,Brasil
It is argued that Centauro events observed in cosmic ray experiments may be characteristic of
only pp and not
pp machines [2],led to some conjectures on the origin of the phenomena,such as genetic correlations,nuclear effects by heavy nucleus,extragalactic source,and others.However,all these conjectures exclude one possibility:that the unusual events could only be associated with pp interactions at sufficiently high energies and not with pp )could be compensated by some kind of suppression effect (pionic component)in matter-matter reactions (pp ).In this communication we shall briefly discuss this conjecture based on one type of physical quantity determined from both cosmic ray and accelerator experiments,namely the total cross section .Since accelerator information on pp interactions are available only below the limiar of production [1],the high mean transverse momentum and multiplicities (characteristics of Centauro events)observed through the emulsion chambers,and not present at lower energies,could originate some additional contributions to the total pp cross sections,that is,higher values than general extrapolations from lower (accelerator)energies usually show.Equivalently,if this extra contribution is present only in the pp channel at sufficiently high energies and not in the pp ones at the energies where Centauro events are observed ,namely,√pp total cross sections at the highest energy region from both accelerator and cosmic ray experiments.In the last case,informations on σt (pp )[3]comes from proton-air cross sections.It is important to observe that antiprotons are not expected to have any significant role in the bulk of these informations and this is a basic point in our argument.Now,since what is extracted in these experiments is the proton-air cross section,the determination of the pp cross section depends,in particular,on nuclear model assumptions [3,4]and this has originated some puzzles and discrepances between different analysis,as clearly shown in Fig.1.Concerning all these results,a central point is the fact that the analysis by Nikolaev seems correct,has never been criticized and the same is true for the Gaisser,Sukhatme and Yodh (GSY)result.Therefore,as qualitatively shown in Fig.1,if we assume that the Nikolaev’s and GSY’s results are the correct ones together with pp data from accelerators (all black symbols in the figure),experimental informations presently available do not rule out an increase of σt (pp )faster than σt (pp channel.Concerning this unusual possibility of a crossing envolving σt (pp )and σt (
pp )−σt (pp )|≤C σt (
logs ∼Clogs,(1)
leading to a wide range of possible extrapolations,including the crossing.Also,the Odderon hypothesis [6](C-odd Regge trajectory)predicts ∆σ∼logs and the approach satisfies analyticity and unitarity.We conclude that general principles and some theoretical approaches,as the Odderon,do not rule out the possibility of an additional contribution in the σt (pp ),leading to a faster increase with the energy than σt (
pp )data.
All the facts presented in this short communication do not ruled out the possibility that an additional contribution toσt(pp)may be present at the highest energies and that it is absent in bothσt(pp)at lower energies and in the pp colliders.
Acknowledgments
I am grateful to E.H.Shibuya,C.O.Escobar and C.D.Chinellato for valuable comments and also to A.F.Martini.
√
pp)andσt(pp)in the interval13.8GeV≤
101001000
10000√s (GeV)30.080.0
130.0
180.0σt o t (m b )。