Characteristics of Pterosaurs
【Paragraph 1】The extinct flying reptiles called pterosaurs were the second group of animals(after insects) to evolve flight.Most pterosaurs were about the size of modern seagulls.A few were as small as sparrows，but some of the later species were the largest flying animals that have ever lived. In1817TheodoreVonSoemmer ring published the first description of a pterosaur fossil，and thinking that it was that of an unusual bat species，he drew his reconstruction with a very bat like posture and wing.His early reconstruction of a pterosaur has haunted the public and scientific perception of pterosaurs ever since.Soemmerring's reconstruction is understandable given that he was the first to try to describe a pterosaur，that few naturalists of the time accepted the idea of major groups of extinct animals，and that both pterosaurs and bats wings consist of a membrane supported by enormously elongated finger bones.So emmer ring showed his pterosaur with the laterally directed legs and reoriented feet of bats and with the wing membrane stretching from the arm and finger along the sides of the body and legs all the way to the ankle.The reconstruction also included a membrane stretching between the legs，similar to that in bats.Even though other scientists developed less bat like descriptions of pterosaurs in the late1800s，the popular literature，and even some scientific literature，continued to describe pterosaurs as bat like into the 1980s.
【 Paragraph 2 】 Bats perch by hanging upside down from tree limbs and roofs of caves.Though many are surprisingly agile climbers，bats are generally awkward when crawling on level surfaces.Did pterosaurs also hang upside down and avoid landing on the ground? Until recently，some paleontologists thought they did，but most scientists now agree that pterosaurs got around on the ground reasonably well. What is still uncertain is whether pterosaurs walked on all fours or just on their hind legs. Pterosaurs' ancestors were bipedal(two-footed) and used their tails to balance their forward-tilted trunks and heads. Early pterosaurs also had long tails sand probably could have run on their hind legs，certainly handy for an animal with wings for forelimbs.These early pterosaurs y however z could have used their forelimbs for walking because their armand hand bones were only slightly enlarged—most of the wing was supported by the gigantic fourth finger.
【 Paragraph 3 】 Later pterosaurs are more enigmatic: their arms and especially their hands seem too long to be used comfortably for walking,but their tails were too short to counterbalance their bodies if they walked just on their hind legs.Birds also have short, stubby tail skeletons, but they manage to walk quite well on their hind legs.Birds manage this by angling the thighs forward to get their feet under the body's center of gravity.They hold their thighs at this unstable angle with extensive hip and thigh muscles Some researchers have suggested that pterosaurs, hipbones were too small to anchor extensive thigh-positioning muscles,but others have responded that pterosaurs* leg and foot bones are so strikingly birdlike that pterosaurs must surely have walked like birds. Recently, however, some pterosaur experts have concluded that a number of fossil trackways—trails of preserved footprints—were made by pterydactyloid pterosaurs,and these animals clearly walked on all four limbs.Perhaps some early pterosaurs walked on their hind legs,but according to current evidence, most species probably walked on all fours.In any case,large pterosaurs,with eight or ten-meterwingspans and weighing as much as an adult human, do not seem likely candidates for a batlike existence confined to clambering about in trees and hanging upside down from branches.
【 Paragraph 4 】 Pterosaurs also possessed some obvious adaptations for powered flight. They had large sternums (breastbones) for attaching powerful flight muscles, well-developed shoulder bones to carry the body's weight in flight, and air-filled bones to lighten the skeleton .? some even had a furcula (a fused breastbone also found in birds): perhaps to flex like a spring and help raise the wings during the upstroke. ? How competent were they at flying? The original batlike reconstructions; along with their class cation as reptiles, suggested to many earlier biologists that pterosaurs were only gliders. ?Biologists now, however, generally agree that pterosaurs were capable of powered, flapping flight. ?Indeed , the shoulder joint is clearly specialized for the down- and-forward, up-and-back movement of normal flapping.
1. In the discussion of Soemmerring in paragraph 1. why does the author mention that "few naturalists of the time accepted the idea of major groups of extinct animals" ?
A. To support the position that Soemmerring was the first to recognize the scientific significance of pterosaur fossils
B. To suggest that Soemmerring reconstruction of the pterosaur went against a commonly accepted position of
C. To help explain why it was reason able for Soemmerring to think that pterosaurs were related to today's bats
D. To indicate how little was known about pterosaurs before Soemmerring published his reconstruction
2. According to paragraph 1, Soemmerring believed that pterosaurs had all of the following features EXCEPT
A. wings that were attached to the sides of the body
B. wings without bones
C. legs that were oriented laterally
D. a membrane between the legs
3. The word "awkward" in the passage is closest in meaning to
4. In paragraph 2 : what evidence suggests that early pterosaurs walked on their hind legs only?
A. The arm and hand bones on early pterosaurs were enlarged
B. The tai ls of pterosaurs may have been long enough to use for balance
C. The trunks and heads of early pterosaurs may have been ti lted forward.
D. The wings of early pterosaurs were largely supported by a single finger.
5. The word "slightly" in the passage is closest in meaning to
A. a little
B. in part
6. The word "strikingly" in the passage is closest in meaning to
7. What evidence is presented in paragraph 3 that at least some pterosaurs walked on all four of their limbs?
A. The position of their feet relative to the body's center of gravity in some pterosaurs
B. The considerable wingspan and weight of some pterosaurs
C. Fossil trackways left by some pterosaurs
D. The shape of the leg bones and feet bones in some pterosaurs
8. According to paragraph 4, what are two indicators that pterosaurs were capable of powered flight? To receive credit, you must select TWO answers.
A. Their shoulder bones allowed the wings to move in more than one direction.
B. Their furcula was separate rather than fused to the breastbone
C. Their bones were filled with air rather than bone t issue
D. Their weight was primarily concentrated in the wing flight muscle.
9. Look at the four squares? that indicate where the following sentence could be added to the passage
Flying was thought to require more energy than cold-blooded reptiles were capable of generating.
Where would the sentence best fit? Click on a square (? ) to add the sentence to the passage.
Pterosaurs also possessed some obvious adaptations for powered flight. They had large sternums (breastbones) for attaching powerful flight muscles, well-developed shoulder bones to carry the body's weight in flight, and air-filled bones to lighten the skeleton. ? some even had a furcula (a fused breastbone also found in birds): perhaps to flex like a spring and help raise the wings during the upstroke. ? How competent were they at flying? The original batlike reconstructions; along with their classification as reptiles, suggested to many earlier biologists that pterosaurs were only gliders. ? Biologists now, however, generally agree that pterosaurs were capable of powered, flapping flight. ? Indeed, the shoulder joint is clearly specialized for the down-and-forward, up-and-back movement of normal flapping.
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.
Soemmerring's description of the pterosaur has had a major impact on people's perception of the creature
A. While Soemmerring recognized certain similarities between pterosaurs and bats, he did not believe the two species were related.
B. In Soemmering's view, bats and pterosaurs had many features 1n common, including the way the wing was attached to the rest of the body.
C. Other than birds, pterosaurs were the only species to have a fused breastbone that could bend when the fore limbs were raised or lowered.
D. Scientists long believed that, like bats, pterosaurs lived in trees and caves.
E. While it seems likely that some early pterosaurs walked on two limbs and some later ones walked on four limbs, biologists remain uncertain about how many pterosaurs walked.
F. Based on various skeletal features, most biologists now believe that pterosaurs were actually capable of powered, flapping flight.