托福阅读真题第248篇Archaeopteryx and Flight
Archaeopteryx and Flight
Paragraph 1: It is not known whether Archaeopteryx, the earliest birdlike creature for which fossils have been found, could fly—but it probably did, at least for short distances. We can make reasoned guesses about how it might have done so, but there is no conclusive evidence about flying in Archaeopteryx because while fossils can tell us about an animal’s physiology, they cannot tell us about an animal's behavior. First, we should look at the methods that animals other than birds use to become airborne. Even though birds have the most astounding abilities of flight, they are not the only creatures to take to the air. Some existing species of frogs, snakes, lizards, and mammals launch themselves from a height and glide for considerable distances in the air. They do so by using skin flaps on the sides of their bodies or by extending broad, sail like limbs. The gliders of Australia are typical examples of this kind of flight. Some of the ancient reptiles living in the late Triassic period more than 200 million years ago used this method of flying. A fossil record of a flying reptile (a saurian) called Protoavis texensis has been dated to that time. That species could represent one of the first steps toward the evolution of birds, but many ancient reptiles had flaps of skin or long scale-like structures that they could have used for gliding or even more sustained flying.
1. The word “conclusive” in the passage is closest in meaning to
O possible
O convincing
O surviving
O favorable
2. The word “extending” in the passage is closest in meaning to
O developing
O spreading
O using
O flapping
3. According to paragraph 1, why have scientists looked for clues to Archaeopteryx flight by studying how other animals fly?
O Complete Archaeopteryx fossils have not been found.
O They discovered the remains of late Triassic reptiles that seemed to fly.
O Archaeopteryx activity cannot be determined from its remains.
O Archaeopteryx fossils are not detailed enough to make important aspects of its physiology clear.
4. In paragraph 1, why does the author provide the information that Protoavis texensis existed in the late Triassic period?
O To support the statement that some early reptiles used the gliding method of flying
O To identify an animal species that was related to Archaeopteryx
O To indicate a flying species that left more fossils than Archaeopteryx did
O To demonstrate the importance of flight for early reptiles
Paragraph 2: Archaeopteryx could have used its feathers to aid gliding after climbing up a high tree, using its finger claws, and then launching itself into the air. This is known as the trees-down hypothesis. Alternatively, it could have used its wings to obtain liftoff after running fast on the ground with its wings flapping. This is known as the ground-up, or cursorial, hypothesis. Archaeopteryx might, for example, have used running and flapping flight to catch insects. This hypothesis links wing use to feeding and takes into account the fact that Archaeopteryx had teeth and fed on meat, either exclusively or among other things. It might have used its feathers simply to provide air resistance (drag) when pouncing on prey. Pouncing might then have turned into swooping as feathers and flight muscles provided better liftoff. Evolving to be smaller in size would have been another factor essential for becoming airborne, but that occurred after the time of Archaeopteryx. In fact, it seems that Archaeopteryx was unable to become fully airborne after running and flapping flight because, given its construction, to provide sufficient energy for takeoff, it would have needed to run much faster than possible.
5. According to the trees-down hypothesis described in paragraph 2, which of the following was true of Archaeopteryx flight?
O Archaeopteryx launched itself in the air in order to begin its climb up a tree
O Archaeopteryx used its feathers to help it climb up trees.
O Archaeopteryx used its feathers to continue travel through the air.
O Archaeopteryx used its finger claws to aid gliding
6. According to paragraph 2, why is the ground-up hypothesis unlikely in the case of the Archaeopteryx?
O It did not have a sufficient number of feathers to sustain itself in the air.
O It could not have run fast enough to take off into the air.
O Its meat-eating teeth suggest that its early flight was linked to hunting in trees.
O It was too small to provide the liftoff essential for flight
Paragraph 3: Another suggestion, no longer popular, is that Archaeopteryx used its winged forelimbs rather like fans to trap insects as it ran along the ground. Later wings evolved and were used in flying. This hypothesis is similar to the idea that feathers first evolved for insulation, in the sense that feathers are said to have first appeared for purposes other than flying. Another alternative is that feathers first evolved for performing the visual displays used in social communication and were only later used for flying. Modern birds use their feathers to communicate, with often spectacular visual displays. It is possible that the first feathered creatures (ancient birds and theropod dinosaurs) used their feathers in similar ways to communicate with other members of their species. Evidence that dinosaurs formed groups supports the idea that they may have communicated using vocalizations or visual displays.
7. Why does the author provide the information in paragraph 3 that modern birds use their feathers to communicate?
O To illustrate how flight has led birds to other types of behavior
O To support one possibility for an early use of Archaeopteryx feathers
O To contrast the use of feathers by modern and ancient species
O To show the extent of social behavior in various species
8. Which of the following statements is supported by both hypotheses discussed in paragraph 3?
O Archaeopteryx flight evolved as a way to capture prey more easily.
O The physical characteristics necessary for flight originally evolved for other uses.
O The original purposes for Archaeopteryx flight are no longer used by modern species.
O The early methods of flight were unsuccessful for long periods of time.
Paragraph 4: None of these hypotheses about the first uses of feathers can help us to decide whether Archaeopteryx was a ground-up or a trees-down flier. It is a matter of putting the many pieces of evidence together and coming up with the most plausible hypothesis, but there is no overwhelming evidence to determine whether Archaeopteryx glided down from above or flapped its way up from a running start on the ground. We can say, however, that only the trees-down hypothesis finds a good use for its hooked finger claws—used to climb up trees. Claws could, of course, be used in a number of different ways—some other ancient birds too large to fly had claws, which they must have used for purposes other than climbing.
Paragraph 1: It is not known whether Archaeopteryx, the earliest birdlike creature for which fossils have been found, could fly—but it probably did, at least for short distances. We can make reasoned guesses about how it might have done so, but there is no conclusive evidence about flying in Archaeopteryx because while fossils can tell us about an animal’s physiology, they cannot tell us about an animal's behavior. First, we should look at the methods that animals other than birds use to become airborne. Even though birds have the most astounding abilities of flight, they are not the only creatures to take to the air. Some existing species of frogs, snakes, lizards, and mammals launch themselves from a height and glide for considerable distances in the air. They do so by using skin flaps on the sides of their bodies or by extending broad, sail like limbs. ■The gliders of Australia are typical examples of this kind of flight. ■Some of the ancient reptiles living in the late Triassic period more than 200 million years ago used this method of flying. A fossil record of a flying reptile (a saurian) called Protoavis texensis has been dated to that time. ■That species could represent one of the first steps toward the evolution of birds, but many ancient reptiles had flaps of skin or long scale-like structures that they could have used for gliding or even more sustained flying. ■
9. Look at the four squares [■] that indicate where the following sentence could be added to the passage
The fossil record shows that these animals are not the first to employ it.
Where would the sentence best fit? Click on a square [■] to add the sentence to the passage
10. 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 most important ideas in the passage. Some sentences 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.
Answer Choices
O In the late Triassic period, several creatures developed the ability to fly, including Archaeopteryx, Protoavis texensis, and various early forms of frogs, snakes, and lizards.
O By running along the ground and flapping its wings, Archaeopteryx may have been able to achieve low-level flight in order to catch prey.
O Though feathers aid flight, Archaeopteryx may have originally evolved feathers for purposes unrelated to flight such as insulation or visual communication.
O Archaeopteryx may have started to fly by climbing up trees and then using its feathers to glide down through the air.
O Archaeopteryx may have developed flight by jumping repeatedly in the air in order to obtain prey in trees, using its feathers to slow its fall to the ground.
O One key to Archaeopteryx flight is the hooked finger claw that was found in the fossil evidence, which makes both major hypotheses generally plausible.
答案
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