TPO64阅读-1Characteristics of Pterosaurs
原文 (1)
译文 (3)
题目 (4)
答案 (8)
背景知识 (8)
原文
Characteristics of Pterosaurs
①The 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.In1817Theodore Von Soemmerring published the first description of a pterosaur fossil,and thinking that it was that of an unus
ual bat species,he drew his reconstruction with a very batlike 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.Soemmerring 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 batlike descriptions of pterosaurs in the late1800s,the popular literature,and even some scientific literature,continued to describe pterosaurs as batlike into the1980s.
②Bats 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 hindlegs. Pterosaurs’ancestors were bipedal(two-footed)and used their tails to balance
their forward-tilted trunks and heads.Early pterosaurs also had long tails and probably could have run on their hindlegs,certainly handy for an animal with wings for forelimbs.These early pterosaurs,however,could have used their forelimbs for walking because their arm and hand bones were only slightly enlarged—most of the wing was supported by the gigantic fourth finger.
③Later 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 hindlegs.Birds also have short,stubby tail skeletons,but they manage to walk quite well on their hindlegs. 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 hindlegs, but according to current evidence,most species probably walked on all fours.In any case,large pterosaurs,with eight-or ten-meter wingspans and wei
ghing 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.
understandable
④Pterosaurs 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.
译文
翼龙的特点
①继昆虫之后，灭绝的飞行爬行动物翼龙是第二个进化出飞行能力的动物。大多数翼龙大约与现代海鸥的身形大小相同。少数与麻雀一样小，但后来的一些物种是有史以来最大的飞行动物。1817年，西
奥多·冯·苏默梅林（Theodore Von Soemmerring）发表了对翼龙化石的首次描述，并认为这是一种不寻常的蝙蝠物种，因此他模仿蝙蝠的姿势和翅膀对翼龙进行了重现描述。从那以后，他对翼龙的早期再现就影响着大众及科学对翼龙的认识。苏默梅林（Soemmerring）的重现描述是可以理解的，因为他是第一个尝试描述翼龙的人，也因为当时很少有博物学家接受翼龙是灭绝动物的主要类的想法，还因为翼龙和蝙蝠的翅膀都有一层由巨长指骨支撑的薄膜。苏默梅林（Soemmerring）呈现的翼龙，有侧向延伸的腿、像蝙蝠一样能重新定向的脚以及从手臂和手指沿着身体的侧面和腿一直延伸到脚踝的膜。重现描述还呈现了翼龙有像蝙蝠一样在双腿之间伸展的膜。尽管其他科学家在19世纪末期对翼龙的蝙蝠状描述较少，但流行文学甚至某些科学文献在二十世纪八十年代仍将翼龙描述为蝙蝠状。
②蝙蝠通过倒吊在树枝和洞穴顶上而栖息。尽管许多蝙蝠擅长攀爬，但在水平地面上爬行时通常是笨拙的。翼龙也倒挂并且避免着陆吗？直到最近，一些古生物学家还认为翼龙是倒挂且避免着陆的，但是现在大多数科学家都认为翼龙是可以在地面上活动自如的。仍然不确定的是翼龙是四肢行走还是仅用后腿行走。翼龙的祖先是两足动物（两足），并用尾巴来平衡前倾的躯干和头部。早期的翼龙也有长长的尾巴，可能是用后腿奔跑，这对于前肢带翅膀的动物来说肯定很方便。但是，这些早期的翼龙本来可能是会用它们的前肢行走，因为它们的手臂和手骨不是很大----大部分的翅膀都由巨大的第四指支撑。
③后来的翼龙更令人困惑：它们的手臂，尤其是手似乎太长了以至于无法舒适地行走，但如果它们只
用后腿走路，它们的尾巴又太短了以至于无法平衡身体。鸟也有粗短的尾巴骨架，但是它们用后腿走得很好。鸟类通过将大腿向前倾斜以使其脚处于身体的重心之下而得以走得很好。由于拥有发达的臀部和大腿肌肉，它们可以使大腿保持在这个不稳定的角度。一些研究人员认为翼龙的臀骨太小了以至于无法支撑大腿发达的肌肉，但是其他人则回应说，翼龙的腿及脚骨和鸟类的特别像以至于翼龙肯定像鸟一样行走。然而，最近，一些翼龙专家总结到翼龙类翼龙留下了许多化石轨迹（被保存下来的足迹），所以这些动物显然是用四肢行走的。也许有些早期的翼龙是用后腿行走，但是根据目前的证据来看，可能大多数翼龙都是四肢行走的。无论如何，大型翼龙的翼展有八到十米，重可达成年人的重量，似乎不可能是以蝙蝠状的形式在树上爬来爬去或倒挂在树枝上。
④翼龙还具有一些明显的动力飞行适应性。它们大的胸骨（胸骨）可以附着强大的飞行肌肉，发达的肩骨可以承受飞行中的体重，且充满空气的骨骼可以减轻骨骼的重量。一些翼龙甚至还有叉骨（鸟类也有的融合胸骨），也许可以像弹簧一样弯曲并在翅膀上拍时帮助抬起翅膀。他们的飞行能力如何？最初的蝙蝠状重现描述以及作为爬行动物使许多早期的生物学家认为翼龙只是滑行类动物。然而，现在的生物学家普遍认为翼龙具有动力、扑翼飞行的能力。确实，肩关节显然是专门用于上下前后扑翼动作的。
题目
1.In the discussion of Soemmerring in paragraph1,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’s reconstruction of the pterosaur went against a commonly accepted position of naturalists at that time
C.To help explain why it was reasonable 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 paragraph1,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
A.careful
B.clumsy
C.slow
D.helpless
4.In paragraph2,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 tails of pterosaurs may have been long enough to use for balance.
C.The trunks and heads of early pterosaurs may have been tilted 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
A.perfectly

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