2017年职称英语综合A类阅读理解练习题(2)
第一篇
"Hidden" Species May Be Surprisingly Common
Cryptic 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 biogeographical 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.
31. 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 restllts 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".
32. What was scientists' understanding of cryptic species?
A. They occurred in equal numbers in all biogeographical regions.
B. They were mostly found in insects find reptiles.
C. They were likely to be in tropical rather than temperate regions.
D. Both B and C.
33. 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.
34. Which of the following about the African bush elephant and the African elephant is true?
A. The WCU are interbreeding those elephants.
B. They are interbreeding species.
C. They are two genetically distant species.
D. They depend on each other for survival.
35. People were confused in their attempts to control malaria in Europe in the early 1900s.because scientists
A. identified only one mosquito species instead of six species.
B. thought only three mosquito species transmitted disease.
C. thought there was only one mosquito species.
D. did not know what species was being studied.
第二篇
Star Quality
A new anti-cheating system for counting the judges' scores in ice skating is flawed, according to leading sports specialists. Ice skating's governing body announced the new rules last week after concerns that a judge at the Winter Olympics may have been unfairly influenced.
Initially the judges in the pairs figure-skating event at the Winter Olympics in Salt Lake City voted 5 to 4 to give the gold medal to a Russian pair, even though they had a fall during their routine. But the International Skating Union suspended the French judge for failing to reveal that she had been put under pressure to vote for the Russians. The International Olympics Committee then decided to give a second gold to the Canadian runners-up ( 亚军).
The ISU, skating's governing body, now says it intends to change the rules. In future 14 judges will judge each event, but only 7 of their scores-selected at random-will count.
The ISU won't finally approve the new system until it meets in June but already UK Sport, the British Government's sports body, has expressed reservations. "I remain to be convinced that the random selection system would offer the guarantees that everyone concerned with ethical sport is looking for," says Jerry Bingham, UK Sport's head of ethics (伦理).
A random system can still be manipulated, says Mark Dixon, a specialist on sports statistics from the Royal Statistical Society in London. "The score of one or two judges who have been nobbled(受理贿赂) may still be in the seven selected."
Many other sports that have judges, including diving, gymnastics, and synchronized swimming, have a system that discards the highest and lowest scores. If a judge was under pressure to favour a particular team, they would tend to give it very high scores and mark down the opposition team, so their scores wouldn't count. It works for diving, says Jeff Cook, a member of the international government body's technical committee. "If you remove those at the top and bottom you're left with those in the middle, so you're getting a reasonable average."
Since the 2000 Olympics in Sydney, diving has tightened up in its system still further. Two separate panels of judges score different rounds of diving during top competitions. Neither panel knows the scores given by the other. "We have done this to head off any suggestion of bias," says Cook.
Bingham urged the ISU to consider other options. "This should involve examining the way in which other sports deal with the problem of adjudicating (裁定) on matter of style and presentation," he says.
36. Who won the gold medal in the pairs figure-skating event?
A. The Russian pair.
B. The Canadian pair.
C. Both the Russian pair and the Canadian pair.
D. The French pair.
37. According to the new rules proposed by the ISU, which of the following is right?
A. The number of judges will be doubled.
B. Only half of the judges will score.
C. Only some selected judges will score.
D. Only half of the scores will count.
38. What does Jerry Bingham express by saying "I remain to be convinced"?
A. His anger.
B. His criticism.
C. His agreement.
D. His doubt.
39. The attitude of those concerned in the UK to the new rules proposed by ISU can be best described as_______.
A. indifferent.
B. reserved.
C. enthusiastic.
D. positive.
40. Which of the following is NOT true of the scoring system for diving?
A. It is more biased.
B. It is more reasonable.
C. It is fairer.
D. It is tighter.
第三篇
Eat More, Weigh Less, Live Longer
Clever genetic detective work may have found out the reason why a near starvation diet prolongs the life of many animals.
Ronald Kahn at Harvard Medical School in Boston, US, and his colleagues have been able to extend the lifespan (寿命) of mice by 18 percent by blocking the rodent's (啮齿动物) increase of fat in specific cells. This suggests that thinness--and hot necessarily diet--promotes long life in "calerie (热量卡) restricted" animals.
"It's very cool work," says aging researcher Cynthia Kenyon of the University of California,San Francisco. "These mice eat all they want, lose weight and live longer. It's like heaven."
Calorie restriction dramatically extends the lifespan of organisms as different as worms and rodents. Whether this works in humans is still unknown, partly because few people are willing to submit to such a. strict diet.
But many researchers hope they will be able to trigger the same effect with a drug once they understand how less food leads to a longer life. One theory is that eating less reduces the increase of harmful things that can damage cells. But Kahn's team wondered whether the animals simply benefit by becoming thin.
To find out, they used biology tricks to disrupt the insulin (胰岛素) receptor (受体) gene in lab mice- but only in their fat cells. "Since insulin is needed to help fat cells store fat, these animals were protected against becoming fat," explains Kahn.
This slight genetic change in a single tissue had dramatic effects. By three months of age,Kahn's modified mice had up to 70 percent less body fat than normal control mice, despite the fact that they ate 55 percent more food per gram of body weight.
In addition, their lifespan increased. The average control mouse lived 753 days, while the thin rodents averaged a lifespan of 887 days. After three years, all the control mice had died, but one quarter of the modified rodents were still alive.
That they get these effects by just manipulating the fat cells is controversial," says Leonard Guarente of the Massachusetts Institute of Technology, who studies calorie restriction and aging.
But Guarente says Kahn has yet to prove that the same effect is responsible for increased lifespan in calorie-restricted animals. "It might be the same effect or there might be two routes to long life,"he points out, "and that would be very interesting."
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