Question

   When hunger pains strike a shark, does it simply swim around aimlessly until it comes across a meal? Scientists who have studied the diving behavior of sharks, turtles, fish, and other marine predators(食肉动物) now suggest that these animals are a bit more strategic(策略的). They appear to follow a special type of random motion, known as a Levy walk.

       Ecologists have long studied how animals find food, with some exploring whether simple rules could explain their hunting behavior. In 1996, one team claimed that wandering albatrosses perform Levy walks, which are characterized by a particular distribution of movement lengths that include many short-distance jumps and rare long jumps. Others then found that many animals used this search strategy, too. But last fall, scientists—including authors of the original 1996 report—reported that the original albatross data were flawed. They also cast doubt on most claims of Levy walks by animals, condemning the small data sets analyzed and a key statistical method many groups used.

       The tables have turned again, however. Behavioral ecologist David Sims and his colleagues have found evidence of Levy walks from depth-sensing recorders they had fixed to 31 large marine predators. As part of the European Census of Marine Life, they analyzed the vertical motion in more than a million dives as the animals obviously hunted for food.

       Using various statistical methods, they showed that during the food-hunting, most animals examined seemed to perform vertical Levy walks, with many short dives with an occasional longer dive, some hundreds of meters deep. Sims argues that his team's vast data sets and the use of diverse statistical analyses make their study “the most believable evidence for Levy-like movement.”

       The study is convincing, says ecologist Frederic Bartumeus of Princeton University. He says that he's impressed with the amount of data Sims' team analyzed and predicts that the study will shift the debate from whether animals perform Levy walks to when they use this strategy and why: “It's going to make biologists less suspicious about the existence of these patterns.”

71. Which of the following animals may not be studied by the ecologists?

A. Turtles.             B. Tigers.                  C. Albatrosses.   D. Whales.

72. The underlined word "flawed" probably means           .

A. stolen                B. proved                  C. faulty              D. missed

73. Why did some scientists cast doubt on Levy walks by animals?

A. Because they didn't believe what David Sims said.

B. Because the authors of the 1996 report made a serious mistake.

C. Because the data sets other scientists analyzed were not convincing.

D. Because they doubted about the statistical method other scientists used.

74. From the passage we can learn that           .

A. David Sims is quite confident of their research result

B. David Sims and his colleagues didn't make enough research

C. Frederic Bartumeus is a member of Sims' research group

D. the existence of Levy walk is still doubtful

75. The passage mainly wants to tell us that           .

A. how marine animals finds their meals

B. ecologists make mistakes frequently during their research

C. Levy walk is a kind of advanced hunting method

D. we should be serious about scientific research

Answer 1

BCDAA