新托福听力讲义生物类段子1

生物学段落 (一) 44. ( A) How insects breed in extreme desert temperature. (B) Different types of beetles. ( C) Plants that survive in arid regions. (D) How beetles can defeat a plant’s defense system.. 45. (A) Its resin isn’t poisonous. (B) It can shoot its resin a great distance. ( C ) Its leaves have no veins. (D) It doesn’t need much water to grow well. 46. (A) By severing the veins that carry the poison. (B) By eating only the stem of the plant. ( C) By changing the plant’s chemistry. (D) By eating only at night. Questions 44 through 46 Listen to a talk in a biology class. This morning I ______________a recent scientific discovery dealing_______________________________. This is about a desert shrub ___________________________six feet. Do you think it would be safe from all attacks by insects? But a recent study has found one insect, a beetle that can chew its way past the plant’s defense system by __________________________. This vein cutting is just one method the beetles used to prepare a safe meal. ________is by cutting a path all the way across the leave to hold the flow of chemicals. Then they simply eat between the veins of poison._________, scientists who studied insect adaptation to plant defenses have focused on chemical responses. That is, how the insects can neutralize or alter the poisonous substances plants produce._____________ this chewing strategy is that the beetle is actually exhibiting a behavioral response to the plant’s defenses rather than the more common chemical response. It is only after a beetle’s survived several encounters with the plant’s resin that it learns how to avoid the poison: by chewing through the resin transporting veins on the next leaf it eats. And thus gives itself a safe meal._________, it can take a beetle an hour and a half of careful vein cutting to prepare a small leaf that takes it only a few minutes to eat.________________________________________ 44. What is the talk mainly about? 45. What is unusual about the desert plant? 46. How can the beetles avoid being poisoned by the plant? Desert shrub poisonous resin (social, solitary) insect , vein, defense, chemical, leaf(leaves), beetle, substance, deliver, transport, chew, cut, neutralize, alter, (二) 44. (A) The adaptations of the African grass mouse to its environment. (B) The sleeping habits of the African grass mouse. (C) The effect of intense sunlight on the diet of the African grass mouse. (D) The habitat of the African grass mouse. 45. (A) It has a flattened shape. (B) It has an extra layer of pigmented tissue. (C) It doesn’t have an extra layer of pigmented tissue. (D) It has a large cranial cavity. 46. (A) They are active during daylight hours. (B) Their heads are exposed to sunlight while they sleep. (C) They have only partially adapted to their tropical environment. ( D) Their wings are easily damaged by ultraviolet radiation. Q44-46 Listen to part of a lecture given by a biology professor. Human populations near the equator have evolved dark skin over many generations because of exposure to the fiercest rays of the sun. A similar phenomenon has also occurred in other parts of the animal kingdom.___________________________________. Most mice are nocturnal, but the African grass mouse is active during daylight hours. ________________it spends its days searching for food in the semi-dry bush in scrubby habitats of eastern and southern Africa. Its furry stripe’s like a chipmunk’s, which helps it blend in with its environment. ________it spends a lot of time in the intense tropical sun, the grass mouse has also evolved two separate safeguards against the sun’s ultraviolet radiation.___________, like the population of humans in this region of the world, the skin of the grass mouse contains lots of melanin, or dark pigment. __________________________this mouse has a layer of melanin-pigmented tissue between its skull and skin. This unique cap provides an extra measure of protection for the grass mouse and three other types of African mouse, like rodents that are active during the day. _________________scientists has identified with the same sort of skull adaptation is the white tent-making bat of the Central American tropics. _____________these bats sleep during the day, they do so curled up with their heads exposed to the sun.. 44. What is the speaker mainly discussing? 45. What is unusual about the head of the African grass-mouse? 46. Why do white tent-making bats need protection from the sun’s rays? (三) 44. (A) To solicit volunteers for Turtle Watch. (B) To give an assignment to a biology. (C) To warn students not to hurt green turtles. (D) To describe the nesting and hatching activities of the green turtles. 45. (A) The lights attract predators. (B) They need to save electricity. (C) The baby turtles are attracted to light. (D) The volunteers use lights for signals. 46. (A) Write a report about their activities. (B) Attend make-up classes with Dr. Webster. (C) Help find turtle eggs before they hatch. (D) Spend two hours working for the project. 三 Questions 44-46 Listen to an announcement given in a university biology class. Hi, I’m Jim Black. Before you get started with class today, Doctor Webster __________________________________the biology department’s ongoing turtle-watch project down the South Beach. As many of you probably know, South Beach is an important nesting site for the green turtle, a type of endangered sea turtle. In the next few days, turtles from several nesting sites reidentified along the beach will hatch and head for the water. __________is that a lot of these hatching will never make it. Raccoons and hungry birds will get many of them before they reach the surf. ________________________going on now so that volunteers will be on hand to protect the turtles after they hatch. Oh, and ______________________________of beach front homes to leave they yard lights off for the next couple of weeks. The baby turtles __________to artificial lights such as torch lights and head lights.__________, some of them end up on the beach highway and are killed by passing cars. So __________________lights on the landward side of the beach. Now if you’re interested, please stop by my office in the biology department and sign up. What are we asking you to do? We’re __________________________________from each participant. Oh, and please note that turtle-watch activities do not constitute excused absences from the class. Thanks. 44. What is the purpose of the talk? 45. Why should homeowners turn their lights off? 46. What do the turtle-watch participants have to do? (四) 43. (A) How animals react to frightening situations. (B) Why mice are particularly fearful animals. (C) Whether fearfulness is a genetic trait. (D) Why certain animals are feared by humans. 44. (A) They fought with the other mice. (B) They stayed close to their mothers. (C) They ran back and forth constantly. (D) They remained close to the wall. 45. (A) The extent of damage to the nervous system. (B) The presence or absence of certain nerve-cell receptors. (C) The size of nerve-cell receptors in the brain. (D) The level of danger in the mammal’s environment. 46. (A) To show the relationship between fearfulness and environment. (B) To give examples of animals that aren’t fearful. (C) To compare fear in mammals to fear in other animals. (D) To identify the nerves that control fear in certain animals. Questions: 43 through 46 Listen to a talk in a biology class. We’ve looking at fear______________________, and someone asked whether the tendency to be fearful is__________. What some studies done with mice indicate that mammals do inherit fearfulness to some degree. In one study, ______________, a group of mice was placed in a brightly lit open box with no hiding place. Some of the mice wandered around the box and didn’t appear to be bothered about being so exposed. But other mice didn’t move. They stayed up against one wall which indicated that they were afraid. Well, when fearful mice, or you might say anxious mice like the ones who stayed in one place, when mice like these were bred with one another repeatedly, after about twelve or so generations, then all of the offspring showed_______________________And even when a new born mouse from this generation was raised by a mother and with other mice who were not fearful, that mouse still tended to be fearful as an adult. Now why is this? Well______________________________________________________. These are genes that _______________________particular nerve-cell receptors in the brain. And the degree of overall of fearfulness in the mammal seems to _________________on the presence or absence of these nerve-cell receptor. And this appears to apply to humans as well by the way.___________ a tendency towards anxiety and fear may well be an inherited trait, the specific form that the fear takes has more to do with the individual’s environment. So a particular fear, like a fear of snakes or the fear of spider, say, is not genetic, but the overall tendency to have fearful responses, is. 43. What is the talk mainly about? 44. How did some of mice in the study demonstrate that they were afraid? 45. According to the professor, what contributes to a mammal’s tendency to be fearful? 46. Why does the professor mention snakes and spiders? (五) 47. (A) How they behave toward ants from other nests. (B) What they usually eat. (C) Why they are becoming extinct. (D) Why they were brought to California. 48. (A) They protect Argentine ants that live in neighboring nests. (B) They gather food with Argentine ants from other nests. (C) They fight Argentine ants from other nests. (D) They gradually build larger nests than other ant species do. 49. (A) They attack members of their own nests. (B) They recruit ants from other species into their nests. (C) They form large colonies made of several nests. (D) They hide from insects that attack their nests. 50. (A) They share the same few ancestors. (B) They can’t be distinguished from native Californian ants. (C) They are evolving faster than native Californian ants. (D) Their future survival is in doubt. Questions 47-50 Listen to part of a talk in a biology class. The professor is discussing insect behavior. Today we’re going to continue our discussion of social insects, _______________the Argentine ant, which, as you might guess, is a species of ant that’s _________Argentina. Well consider what happened to this type of ant after some members of this species moved to California from their original habitat. OK, Well, in Argentine, these Argentine ants behave like most ants species around the world. They__________________ of the same species if those ants are from some other nest.________________ the Argentine ants living in Californian___________________. Ants from different nests form a single large colony. Within this colony there is __________________among ants from different nests. And when they fight in sex from outside their colony, the Argentine ants can quickly recruit a huge army from their network of nests. This of course gives them advantage over other ant species. So then, why do Argentine ants behave differently in California than they do in Argentine? Well, using____________, researchers found that all the Argentine ants in California, their population must’ve been very small. And all the later generation of Argentine ants there must’ve descended from_______ few ancestors. So they’re all closely related. This discovery is important because for most social insects, membership in a colony is based on how closely related they’re genetically. 47. What aspect of Argentine ants is mainly discussed? 48. What does the professor say about the Argentine ants that live in Argentina? 49. What is the characteristic behavior of Argentine ants in California? 50. What did genetic testing indicate about the Argentine ants in California? (六) 39. (A) How most species of spiders reproduce. (B) How one species of spiders of spider feeds its young. (C) How spiders defend their territory. (D) How Darwin experimented with spiders. 40. (A) They eat one another. (B) They eat insects that they catch. (C) They build a new nest. (D) They are attacked by other species of spiders. 41. (A) No two members of a species are exactly alike. (B) A single species may evolve into two separate species. (C) Primitive life-forms evolve into more advanced life-forms. (D) The survival of the strongest in a species contribute to the survival of that species. Questions 39-41 Listen to part of a talk in a biology class. Before moving on to a new topic, I want to finish up our unit on a rag nit, by looking at what may seem a very unusual aspect of spider behavior---a species where ___________________________________________. Unlike most other spiders this species lays one and only one-clutch of forty eggs in a life time. The young spiders hatch in mid-spring or early summer inside a nest of eucalyptus leaves. Their mother spends the warm summer months bringing home large insects, often ten times their weight for meals. The catch is always ____________more than her young spiders can eat. So the mother fattens herself up on this extra prey, and stores the nutrients in her extra unfertilized eggs. As the weather turns colder, there are fewer insect prey hunts. That’s when the nutrients stored in those extra eggs begin to seep into the mother’s blood stream. So when there are no more insects to feed to the young spiders, they attach themselves to the mother’s leg joints and draw nourishment by sucking the nutrient-rich blood. After several weeks, the mother is ____________all nutrients and diets. But then how do the young get nourishment? They start to ______________Now if you recall our discussion of Darwin, you’ll see the evolutionary value of this. Only the __________spiders of the clutch will survive this cannibalism. And the mother spider will ensure that her genes have an increased chance of survival through future generations. 39. What is the talk mainly about? 40. What happens after the mother of the young spiders dies? 41. What idea of Darwin does the professor relate to the spider’s behavior? (七) 43. (A) Reproduction in echinoderms. (B) How fish avoid their enemies. (C) The form and life-cycle of starfish. (D) The feeding habits and digestive systems of starfish. 44. (A) It consists of a protective film. (B) It is covered with scales. (C) It can be shed easily. (D) It is covered with sharp bumps. 45. (A) To explain how a starfish reproduces. (B) To illustrate the shape of a starfish. (C) To demonstrate the defense mechanisms of starfish. (D) To show how larvae change into adult starfish. 46. (A) It generates a new one. (B) It cannot swim. (C) It is easily caught. (D) It dies soon afterward. 47. (A) Their diet. (B) The shape of their bodies. (C) Where they feed. (D) Their method of defense. Questions 43-47 Listen to a talk by a marine biologist in an aquarium. Welcome to our aquarium. As we begin our tour, the first animal we will see today is the starfish. You probably have seen pictures of the starfish, but_____________ you will see some live ones and learn a little about______________________. First of all, starfish are not really fish, they belong to the family of echinoderms which are spiny skinned sea animal that is, their skin_____________ thorny bumps. Most starfish have five arm-like extensions on their bodies. And so they look like a five-pointed star. But some other kinds have as many as 40 or more arms. Starfish, like other members of the echinoderm family, have what’s called radial symmetry. All that means is that the body parts of these animals are arranged around the center, kind of like spokes of a wheel around a hub. ______________________of the starfish is that it can drop off arms as a defensive reaction, to get away from an attacker, for example. They can then grow new arms to replace the old ones. Starfish reproduce by releasing eggs into the sea. These eggs develop into larvae, and can swim freely. There early forms which are what larvae are, differ from adult starfish, _______________the larvae have bilateral symmetry. That means that the two halves of the larvae look exactly the same, which makes them ____________________from the later form of the starfish. Eventually the larvae sink to the ocean bottom and change into the adult radial form. If you don’t have questions, we will go in now and see some of the creatures in person. 43. What is the talk mainly about? 44. What does the speaker say about the skin of echinoderms? 45. Why does the speaker give example of a hub of a wheel surrounded by spokes? 46. What happens if a starfish loses an arm? 47. What is the major difference between newly developed and adult starfish? (八) 47. (A) To create space for a temporary exhibit. (B) To reflect changes in scientific theory. (C) To make use of the latest technology. (D) To display newly acquired fossils. 48. (A) It had aggressive tendencies. (B) It is connected to modern birds. (C) It was the largest dinosaur. (D) Its tail usually dragged on the ground. 49. (A) They ate from the same time period. (B) They share similar physical traits. (C) They ate only water plants. (D) They lived in a hot humid climate. 50. (A) According to their size. (B) According to the region of the world they lived in. (C) According to what they ate. (D) According to when they lived. 47-50 Listen to talk given at a museum of natural history. I’d like to welcome you all to the museum of natural history. Today’s tour will take us through our newly-renovated dinosaur exhibit, where we have the largest collection of dinosaur fossils anywhere in the world. Before we begin the tour let me mention that there have been some major modifications to some of the exhibits over the past three years. ____________these changes were made ____________the recent changes in the way scientists interpret dinosaur behavior. For example, when we get to the first room, you will be able to see that tyrannosaurus rex skeleton is no longer standing upright with its tail dragging on the floor. That’s because paleontologist, as they examine the area around its footprints more closely, realized they could find no evidence of a heavy dragging tail, which would have left behind marks in the earth. In its new position, the backbone is parallel to the floor, its head is pushed forward and its tail is stretched out acting as a counterweight. _____________________stresses the relationship between dinosaurs and modern birds and supports the theory that dinosaurs are actually more closely related to birds than to any other existing creature. Let me also point out that we have changed the way we group dinosaur in our displays. There is a new school of thought called kledistics where scientists determine relationships among the animals _______________________________________. The plateosaurus and the ovirapter, for instance, are separated by 148 million years, but they are grouped together here because they both have a grassbean forefoot and its S-shaped neck. Physical evidence that they are indeed related. So now the exhibition halls are arranged more like a family tree_____________ the walk-through time that they used to be. 47. Why has the museum modified the dinosaur exhibit? 48. According to the speaker, what is the tyrannosaurus rex new position evidence of? 49. Why are the plateosaurus and the ovirapter displayed together? 50. How were dinosaurs originally grouped in the exhibit?