What was scientists' understanding of cryptic species?A．They occurred in equal numbers in all biogeographical regions.B．They were mostly found in insects and reptiles.C．They were likely to be in tropical rather than temperate regions.D．Both Ｂ and Ｃ.
What was scientists' understanding of cryptic species?
A．They occurred in equal numbers in all biogeographical regions.
B．They were mostly found in insects and reptiles.
C．They were likely to be in tropical rather than temperate regions.
D．Both Ｂ and Ｃ.
相关考题：
Nowadays children in this area are taught at school()at home, but 60 years ago no children were taught at school()those from rich families. A、rather than; other thanB、other than; exceptC、other than; rather thanD、besides; except
He had more dictionaries than_________ for his work.() A.they are neededB.were necessaryC.it was neededD.necessary were they to him
"Hidden" Species May Be Surprisingly CommonCryptic species animals that appear identical but are genetically quite distant—may be much more widespread than previously thought. The findings could have major implications in areas ranging from biodiversity estimates and wildlife management, to our understanding of infectious diseases and evolution.Reports of cryptic species have increased dramatically over the past two decades with the advent of relatively inexpensive DNA sequencing technology. Markus Pfenninger and Klaus Schwenk, of the Goethe-Universitat, in Frankfurt, Germany, analyzed all known data on cryptic animal species and discovered that they are found in equal proportions throughout all major branches of the animal kingdom and occur in equal numbers in all biogeographieal regions.Scientists had previously speculated that cryptic species were predominantly found in insects and reptiles, and were more likely to occur in tropical rather than temperate regions. "Species that are seemingly widespread and abundant could in reality be many different cryptic species that have low populations and are highly endangered. " Says Pfenninger. Until the genetic information of all species in at least one taxon is thoroughly studied, no one will know just how many cryptic species exist. "It could be as high as 30%. " Pfenninger says."I'm extremely surprised by their results. " Says Alex Smith of the University of Guelph in Ontario, Canada. "It's a call to arms to keep doing the broad kind of genetic studies that we are doing. "Sampling as many individuals as possible, scientists hope to complete work on all fish and birds in another 5 to 10 years. Once either of these taxonomic groups is completed, Pfenninger says researchers will be able to decide how many cryptic species exist throughout the animal kingdom.Examples of cryptic species include the African elephant. A 2001 study found the elephants were actually two genetically distinct, non-interbreeding species, the African bush elephant and the African elephant. The species are currently listed as vulnerable and threatened, respectively, by the World Conservation Union (WCU).The reclassifications are more than an academic exercise. They define populations that have evolved independently of each other and whose genetic differences can have significant consequences. In the early 1900s misidentification of mosquito species based on morphology confused attempts to control malaria in Europe. Ultimately, what was thought to be a single species was actually made up of six sibling species, only three of which transmitted the disease. "The basic unit in biology is always the species, and you have to know what you are dealing with. " Pfenninger says. Much previous research is now no longer used, he says, because it is not clear what species was being studied.Which of the following about the significance of the research on cryptic species is NOT true?A．The results of the research can help the development of many other research areas.B．The results of the research can help the development of biodiversity estimates.C．The results of the research can help our understanding of infectious disease evolution.D．The results of the research can help our understanding of "survival of the fittest. "
Do scientists know how many cryptic species exist?A．Not yet.B．Yes, they do.C．They will know the answer in another one or two years.D．They will never know the answer.
The audience, ______, enjoyed the performance.A. most of them were studentsB. most of whom were studentsC. whom they were studentsD. they were mostly students
Socat snared wih Confucius the idea the__________ .A.all men were equal when they were bornB.the lowr classes should be ruled gby the upper classC.the purpose of man was to seek freedom and wisdomD.people should not ask others to do what they did not want to
The insects would devour all our crops and kill our flocks and heads, if _____ for the protection we get from insect-eating animals.A. it is notB. it were notC. were it notD. they were not
What is true about the apartments Mies building Chicago's Lake Shore Drive?A．They ignored details and proportions.B．They were built with materials popular at that time.C．They were more spacious than neighboring buildings.D．They shared some characteristics of abstract art.
What might be the cause of the childrens sickness?A. The crops didnt do well.B. There were too many insects.C. The visitors brought in diseases.D. The pesticides were overused.
What do we know about the rich men in the 17th century?A.They tended to wear clothes without bottons.B.They were interested in historical matters.C.They were mostly dressed by servants.D.They drew their swords from the left.
Social change is more likely to occur in societies where there is a mixture of different kinds of people than in societies where people are similar in many ways. The simple reason for this is that there are more different ways of looking at things present in the first kind of society. There are more ideas, more disagreements in interest, and more groups and organizations with different beliefs. In addition, there is usually a greater worldly interest and greater tolerance in mixed societies. All these factors tend to protnote social change by opening more areas of life to decision.In a society where people are quite similar in many ways, there are fewer occasions for people to see the need or the opportunity for change because everything seems to be the same. And although conditions may not be satisfactory, they are at least customary and undisputed.Within a society, social changes is also likely to occur more frequently and more readily in the material aspects of the culture than in the non-material, for example, in technology rather than in values; in what has been learned later in life rather than what was learned early; in the less basic and less emotional aspects of society than in their opposites; in the simple elements rather than in the complex ones; in form rather than in substance; and in elements that are acceptable to the culture rather than in strange elements.Furthermore, social change is easier if it is gradual. For example, it comes more readily in human relations on a continuous scale rather than one with sharp difference. This is one reason why change has not come more quickly to Black Americans as compared to other American minorities,because of the sharp difference in appearance between them and their white counterparts.According to the passage, which of the following is NOT true?A.Social change tends to meet with more difficulty in basic and emotional aspects of society.B.Disagreement with and argument about conditions tend to slow down social change.C.Social change is more likely to occur in the material aspect of society.D.Social change is less likely to occur in what people learned when they were young.
Warmer climate will bake tropical bugs Global warming could cook tropical insects, with unpredictable knock-on effects, say researchers who warn that rising temperatures also_____(51)tropical frogs and lizards(蜥蜴). Temperatures are_____(52)to increase much faster in temperate(温和的)and polar(极地的)regions than in the tropics. But no-one had looked at how warming would affect insects and other cold-blooded animals_____(53)had evolved in tropical regions with little temperature variation. Curtis Deutsch at the University of California at Los Angeles and colleagues analysed data_____(54)insect survival and reproduction for 38 species in different ecosystems(生态系统), and then estimated how these values would_____(55)with predictions of climate change for the 21st century. The team found that the reproductive_____(56)of tropical insects tends to peak very close to the temperatures where they normally live, but_____(57)sharply at higher temperatures. This means that cranking up(提高)the heat only a small amount can exert a heavy toll, leaving insects unable to reproduce_____(58)enough to keep up their numbers. Temperate insects reproduce well over a broader range, and do not live as_____(59)to their thermal(热的)limit, so they can reproduce successfully when their climate warms more than in the tropics. "Tropical insects do very well in a narrow band of temperatures, but move them above that_____(60)and they die," says team member Josh Tewksbury of the University of Washington in Seattle. The heart of the_____(61)is temperature tolerance. Temperate-zone insects have evolved to survive the much broader temperature swings of seasonal climates, than have their tropical relatives. The_____(62)appears worse for animals that live in hot stable climate of the lower levels of tropical forests. Lizards in clear areas can find shade to cool down, but those living in the forest are already in the_____(63), and there's not much they can do to get cooler, Deutsch says. Too few tropical insects have been studied so far to_____(64)if any particular group will be particularly hard-hit, says Tewksbury. Insects play important_____(65)in forest ecology(生态学). The team are now starting to evaluate how temperature affects ecological interactions of insects with other species, including crops such as African corn.文章(51~65)_____ A.treat B.threaten C.help D.protect
Social change is more likely to occur in societies where there is a mixture of different kinds of people than in societies where people are similar in many ways． The simple reason for this is that there are more different ways of looking at things present in the first kind of society． There are more ideas,more disagreements in interest,and more groups and organizations with different beliefs． In addition, there is usually a greater worldly interest and greater tolerance in mixed societies． All these factors tend to promote social change by opening more areas of life to decision． In a society where people are quite similar in many ways, there are fewer occasions for people to see the need or the opportunity for change because everything seetns to be the same． And although conditions may not be satisfactory, they are at least customary and undisputed． Within a society, social change is also likely to occur more frequently and more readily in the material aspects of the culture than in the non-material, for example, in technology rather than in values; in what has been learned later in life rather than what was learned early; in the less basic mad less emotional aspects of society than in their opposites ; in the simple elements rather than in the complex ones; in form rather than in substance; and in elements that are acceptable to the culture rather than in strange elements． Furthermore, social change is easier if it is gradual． For example, it comes more readily in human relations on a continuous scale rather than one with sharp difference． This is one reason why change has not come more quickly to Black Americans as compared to other American minorities, because of the sharp difference in appearance between them and their white counterparts． According to the passage, which of the following is NOT true?A. Social change tends to meet with more difficulty in basic and emotional aspects of society．A. Social change tends to meet with more difficulty in basic and emotional aspects of society．B. Disagreement with and argument about conditions tend to slow down social change．C. Social change is more likely to occur in the material aspect of society．D. Social change is less likely to occur in what people learned when they were young．
The author easily built a team of his company because __________.A.they were underpaid at their previous jobsB.they were turned down by other companiesC.they were confident of the author and his businessD.they were satisfied with the salaries in his company
The earliest immigrants to North America found Indians already living there．The Indians numbered about 500,000 at that time．Their society was a primitive society,but they lived peacefully and welcomed the white strangers to the land．However,these early immigrants from Europe didn't want to share the land with the natives．They killed off many of the Indians,seized their land or pushed them off to lands farther away．Today the Indians,not more than half a million,live in poverty and misery on the land on which they were once masters.The earliest immigrants were the Spanish,who settled in the southern part of what is now the US．The next large group were the English,after the English came the French,Dutch,Irish,Germans,and other nationality groups,mostly European.Another early group to arrive were the Negroes．But they were brought in as slaves from Africa．They didn't win freedom till generations later.Why didn't the immigrants share the lands with the natives?A.They thought the Indians were not friendly to theB.They wanted to seize the lands as their owC.Because North America was first discovered by theD.Because the Indian people liked making war to the
The earliest immigrants to North America found Indians already living there．The Indians numbered about 500,000 at that time．Their society was a primitive society,but they lived peacefully and welcomed the white strangers to the land．However,these early immigrants from Europe didn't want to share the land with the natives．They killed off many of the Indians,seized their land or pushed them off to lands farther away．Today the Indians,not more than half a million,live in poverty and misery on the land on which they were once masters.The earliest immigrants were the Spanish,who settled in the southern part of what is now the US．The next large group were the English,after the English came the French,Dutch,Irish,Germans,and other nationality groups,mostly European.Another early group to arrive were the Negroes．But they were brought in as slaves from Africa．They didn't win freedom till generations later.Who were the earliest people living in North America?A.The SpanisB.The EnglisC.The NegroeD.The Indian
Text 1"The love of money",St Paul memorably wrote to his protege Timothy,"is the root of all evil.""All"may be putting it a bit strongly,but dozens of psychological studies have indeed shown that people primed to think about money before an experiment are more likely to lie,cheat and steal during the course of that experiment.Another well-known aphorism,ascribed to Benjamin Franklin,is"time is money".If true,that suggests a syllogism:that the love of time is a root of evil,too.But a paperjust published in Psychological Science by Francesca Gino of Harvard and Cassie Mogilner of the University of Pennsylvania suggests precisely the opposite.Dr Gino and Dr Mogilner asked a group of volunteers to do a scries of what appeared to be aptitude tests.As is ofien the case in such experiments,though,what the voiunteers were told.and what the truth was,were rather different things.In the first test they were asked to make,within three minutes,as many coherent sentences as they could out of a set ofwords they had been presented with.What they were not told was that each of them had been assigned to one of three groups.Some volunteers'word sets were seeded with ones associated with money,such as"dollars","financing"and"spend".Some were seeded with words associated with time（eg,"clock",/'hours","moment"）.And some were seeded with neither.Thus unknowingly primed,the volunteers were ready for the second test.This was mathematical.They were given a sheet of paper with 20 matrices which each contained 12 numbers.two of which added up to ten（for example,3.81 and 6.19）.They had to write down,on a separate answer sheet,how many of these pairs they could manage to find in five minutes.They were also given a packet ofmoney and told they could reward themselves with a dollar for each pair they discovered.This led Dr Gino and Dr Mogilner to suspect that self-reflection played a part in controlling uncthical behaviour during the test.They therefore conducted a third test in which,for half the volunteers,there was a mirror in the cubicle they were sitting in when doing the experiment.Volunteers primed to think about money cheated 39%of the time when a mirror was present but 67%when it was not.Those primed to think about time cheated 32%of the time in the presence of the mirror and 36%in its absence-results that are statistically indistinguishable.Finally,a fourth experiment asked primed volunteers to fill in a questionnaire before tackling the matrix.In among"filler"questions intended to disguise what was happening this asked them to rate how they felt about self-reflective statements like,"Right now,1 am thinking about who I am as a person."As in the previous tests,those primed with money words cheated more ofien than those primed with neutral words and far more ofien than those primed with time words.But whether someone cheated was also related to how strongly he felt about the self-reflective statements presented to him in the questionnaire.It seems,then,that thinking about time has the opposite effect on people from thinking about money.It makes them more honest than normal,rather than less so.Moreover,the more reflective they are,the more honest they become.There must be an aphorism in that.What can we infer from the tests?A.The subjects have been told their assignmentB.Volunteers who had been primed with money ideas were more likely to cheat others.C.12%volunteers had been primed with time-related words.D.33%subjects had been primed with money-related words.
共用题干SleepingPeople who sleep for more than eight hours a night do not live as long as those who sleep for six hours,according to the biggest study yet into sleep patterns and mortality（死亡率）.Scientists have no explanation for the findings and do not know if they mean people who like a lie-in（睡懒觉）can extend their lives by sleeping less.Although it is a common belief that sleeping for at least eight hours a night is vital forhealth and well-being,the six-year study involving more than 1.1 million Americans older than 30 found that those who slept for less than eight hours were far from doing themselves any long-term harm."Individuals who now average 6.5 hours of sleep a night can be reassured that this is a safe amount of sleep.From a health standpoint,there is no reason to sleep longer,"said Daniel Kripke , a professor of psychiatry（精神病学）at the University of California, San Diego.Dr. Kripke said,"We don't know if long sleep periods lead to death.Additional studies are needed to determine if setting your alarm clock earlier will actually improve your health."The scientists,who were funded by the American Cancer Society,found that the best survival rates were among the men and women who slept for seven hours a night.Those who slept for eight hours were 12 per cent more likely to die during the six-year period of the study,when other factors such as diet and smoking were taken into account.Even those who spent a mere five hours a night in bed lived longer than those who slept eight or more hours.However,an increasing death rate was found among those who slept for less than five hours.Dr. Kripke said,"Previous sleep studies have indicated that both short-and long-duration （持续时间）sleep had higher mortality rates. However, none of those studies were large enough to distinguish the difference between seven and eight hours a night,until now." The findings indicate that it is all right to sleep for 6.5 hours a night.A:Right B:Wrong C:Not mentioned
共用题干SleepingPeople who sleep for more than eight hours a night do not live as long as those who sleep for six hours,according to the biggest study yet into sleep patterns and mortality（死亡率）.Scientists have no explanation for the findings and do not know if they mean people who like a lie-in（睡懒觉）can extend their lives by sleeping less.Although it is a common belief that sleeping for at least eight hours a night is vital forhealth and well-being,the six-year study involving more than 1.1 million Americans older than 30 found that those who slept for less than eight hours were far from doing themselves any long-term harm."Individuals who now average 6.5 hours of sleep a night can be reassured that this is a safe amount of sleep.From a health standpoint,there is no reason to sleep longer,"said Daniel Kripke , a professor of psychiatry（精神病学）at the University of California, San Diego.Dr. Kripke said,"We don't know if long sleep periods lead to death.Additional studies are needed to determine if setting your alarm clock earlier will actually improve your health."The scientists,who were funded by the American Cancer Society,found that the best survival rates were among the men and women who slept for seven hours a night.Those who slept for eight hours were 12 per cent more likely to die during the six-year period of the study,when other factors such as diet and smoking were taken into account.Even those who spent a mere five hours a night in bed lived longer than those who slept eight or more hours.However,an increasing death rate was found among those who slept for less than five hours.Dr. Kripke said,"Previous sleep studies have indicated that both short-and long-duration （持续时间）sleep had higher mortality rates. However, none of those studies were large enough to distinguish the difference between seven and eight hours a night,until now." All the participants were from the state of California.A:Right B:Wrong C:Not mentioned
共用题干第一篇The Relationship between IQ and Being a VegetarianA Southampton University team found that people who were vegetarians (素食主义者）by 30 had recor-ded five IQ points higher on average at the age of]U.Researchers said it could explain why people with a higher IQ were healthier as a vegetarian diet was linked to lower heart disease and obesity（肥胖）rates.The study of 8,179 people was reported in the british Medical Journal.Twenty years after the IQ tests were carried out in 1970,366 of the participants said they were vegetarians一 although more than 100 reported eating either fish or chicken.Men who were vegetarians had an IQ score of 106,compared with 101 for non-vegetarians;while female vegetarians averaged 104,compared with 99 for non-vegetarians.There was no difference in the IQ scores between strict vegetarians and those who said they were vegetarians but reported eating fish or chicken.Researchers said the findings were partly related to better education and higher class,but it remained statistically significant after adjusting for these factors.Vegetarians were more likely to be female,to be of higher social class and to have higher academic or vocational qualifications than non-vegetarians.However,these differenIces were not reflected in their annual income,which was similar to that of non-vegetarians.Lead researcher Catharine Gale said,"The findings that children with greater intelligence are more likely to report being vegetarians as adults,together with the evidence on the potential benefits of a vegetarian diet on heart health,may help to explain why a higher IQ in childhood or adolescence is linked with a reduced risk ofcoronary heart disease in adult life."But Dr Frankie Phillips of the British Dietetic Association said, "It is like the chicken and egg."Dopcople become vegetarians because they have avery high IQ or is it just that they are clever enough to bemore aware of health issues?It was found in the research that______________.A:most of the participants became vegetarians 20 years after the IQ tests were carried out B:vegetarians who ate fish or chicken were of similar intelligence with strict vegetariansC:female vegetarians were more likely to have higher annual income than non-vegetariansD:vegetarians were more likely to have higher annual income than non-vegetarians
单选题The skulls and pelvic bones of some species of dinosaur share characteristics with the skulls and pelvic bones of all modern birds. Even though not all dinosaurs have these characteristics, there are scientists who claim that all animals that do have these characteristics are dinosaurs. If the statements above and the claim of the scientists are true, which of the following must also be true?ABirds share more characteristics with dinosaurs than they do with other animals.BSome ancient dinosaurs were indistinguishable from modern birds.CAll animals whose skulls share the characteristics of those of modern birds also have pelvic bones that are similar to those of modern birds.DModern birds are dinosaurs.EAll dinosaurs are birds.
单选题In cases where asbestos were employed, it was recommended that it should be used in abonded form with materials such as cement,in order loose fibers were less likely to enter the air.Ain order thatBrather thanCso thatDother than
单选题Which of the following is TRUE?AIn the 1920s, women were limited to being teachers, nurses or office workers.BWomen mainly paid their attention to how they were paid in the 1960s.CWomen asked to change “all men are created equal” into “all human beings are created equal”.DNo states have ever provided women with jobs in the government.
单选题Which of the following is not directly related to Neo-classicism in the eighteenth century?AReason rather than emotion is emphasized.BMost of the writings were didactic and satirical.CLyrical poetry flourished.DPoets found closed couplet the only possible verse form for serious work.
单选题Prolonged and unseasonable frosts produce frost rings in deciduous trees, which grow in moderate climates. Frost rings do not appear in any of the fossilized deciduous trees that have been found in Antarctica. Hence, it is unlikely that such frosts occurred in Antarctica at the time the fossilized trees lived. Which of the following is an assumption on which the argument depends?AThere are fossilized nondeciduous trees from Antarctica that bear frost rings.BDeciduous trees are more likely to bear frost rings than are other tree varieties.CThe process of fossilization does not completely obscure frost rings in deciduous trees.DPresent-day deciduous trees are more sensitive to changes in temperature than were the deciduous trees of ancient Antarctica.EProlonged and unseasonable frosts that might have occurred in Antarctica when the now-fossilized trees were still living did not always produce frost rings in deciduous trees.