TEXT TWO

When Archaeopteryx, a feathered skeleton that was seemingly half dinosaur and half bird, turned up in 1862—three years after the publication of “The Origin of Species”—the origin of birds became a subject of raging debate among palaeontologists. Suggestions that they were the direct descendants of theropod dinosaurs (a group of bipedal meat-eaters that include Allosaurus, Velociraptor and Tyrannosaurus) caused quite a flap. Today, most researchers agree that birds are, indeed, a branch of the Dinosauria. How they made the transition from the land to the sky, though, has yet to be agreed. But a paper in this week’s Current Biology, by Christopher Glen and Michael Bennett of the University of Queensland, makes a strong case that they did it by jumping.

Considering the diversity of life on Earth, flight is surprisingly rare. It has evolved only four times: among the insects about 300m years ago, the pterosaurs (230m), the birds (150m) and the bats (50m). That suggests it is a hard trick to pull off. For birds, there is general agreement that feathers came before flight. Fossils from north-eastern China show animals that had feathers but clearly could not have flown, as well as ones that look like proper birds. The best guesses are that feathers evolved either for insulation (as fur did in mammals) or for display, and that natural selection took advantage by turning them into a means of transport.

There are two broad schools of thought about what happened next. One argues that birds’ immediate ancestors lived in trees. Members of this school think that powered flight developed as a natural extension of gliding (such controlled falling is used as a way of travelling from tree to tree by several arboreal species today). Gliding itself developed because of the lift provided by feathered forearms.

The alternative is that flight evolved on the ground. Some researchers who belong to this school of thought suggest that the power provided by flapping protowings may have given their owners an edge in the pursuit of prey. Others hypothesise that feathery forearms helped animals steer and stabilise themselves.

Unfortunately, behaviour does not fossilise, so it looked as though the question might never be answered. But Dr Glen, a palaeobiologist, and Dr Bennett, a biomechanic, think they have worked out how to do so. Their crucial observation is that in modern birds the curvature of the third toe (which carries a lot of weight during walking and climbing) varies with species’ lifestyles. Birds that spend lots of time climbing around on the trunks of trees have dramatically curved third toes. Those that hop around on branches have mildly curved ones. Those that forage mainly on the ground have the least curved of all.

The two researchers compared these observations with their findings for the bird-like dinosaurs and dinosaur-like birds of China. They noticed that the toes of both feathered dinosaurs and of the earliest flying birds were similar to those of modern birds that spend most of their time on the ground. Flight, in other words, came before birds took to the trees. They are not fallen angels, but risen reptiles.

1. Which one of the following statements is NOT true of the current debate on the origin of birds?

[A] The opinion that birds were the direct descendants of dinosaurs gives the world a shock.

[B] Palaeontologists have get consensus on the specie’s transition from the land to the sky.

[C] Palaeontologists have different opinions on the process of the transition.

[D] The paper in this week’s Current Biology demostrate that the specie moved by hopping before they flied.

2. The reason why flight is surprisingly rare is that _____

[A] life on earth is diversified.

[B] many species of this kind were eliminated during evolution.

[C] feathers evolved not for a means of transport.

[D] it is very hard to have such evolution.

3.The two schools of thought have different opinions on _____

[A] the functions of feathered forearams in transition from ground to sky.

[B] the location of living place before the animals’ evolution to birds.

[C] the development of powered flight.

[D] the power provided by either gliding or flapping.

4. The conclusion of the study carried out by Dr. Glen and Dr. Bennet is that_____

[A] powered flight developed as feathered forearms provided lift.

[B] flight evolved on the ground before they descend on the trees.

[C] earliest birds share similar toes with their modern counterparts.

[D] earliest flying birds evovled from feathered dinosaurs.

5.Which one of the following statements is NOT true of opinions of Dr. Glen and Dr. Bennet?

[A]Birds realized the transition from reptile to flight by jumping.

[B] Dinasaurs are, as a matter of fact, the direct ancester of birds.

[C]Feathers evolves not for the purpose of flight.

[D] Bird’s behaviors is indeed fossilised by their various shape of the third toe.

篇章剖析：

这篇文章讲述了关于鸟类进化的一些研究情况。第一段讲述研究者对于鸟类如何从陆地转到空中生活的进化史有一定的分歧;第二段讲述了鸟类羽毛出现的过程;第三、四段讲述了两派不同看法;第五、六段讲述研究者根据鸟类脚趾情况断定了上述转化是如何发生的。

词汇注释：

Archaeopteryx n. 始祖鸟 palaeontologists n. 古生物学家

theropod adj. 兽脚亚目的 bipedal adj. 两足动物的

Allosaurus n. 异龙 Velociraptor n.

Tyrannosaurus n. 暴龙 arboreal adj. 树栖的

biomechanic n. 生物力学家 curvature n. 弯曲

hop v.跳跃 forage v. 翻寻搜寻食物

难句突破：

(1) When Archaeopteryx, a feathered skeleton that was seemingly half dinosaur and half bird, turned up in 1862—three years after the publication of “The Origin of Species”—the origin of birds became a subject of raging debate among palaeontologists.

[主体句式] When Archaeopteryx turned up …, the origin of birds became…

[结构分析] 这是一个复合句，when引导的是时间状语从句。

[句子译文] 当始祖鸟——一种一半是恐龙一半是鸟类的羽毛动物——的骨架出现在1862年，也就是《物种起源》出版的三年后，鸟类的起源成为古生物学家激烈争论的主题。

(2) Fossils from north-eastern China show animals that had feathers but clearly could not have flown, as well as ones that look like proper birds.

[主体句式] Fossils …show animals … as well as ones …

[结构分析] 这是一个复合句。两个that引导的都是定语从句修饰前面的名词。

[句子译文] 华东发现的化石表明拥有羽毛的动物当时不一定能飞行，即使那些看起来完全像鸟类的也是这样。

题目分析：

1. Which one of the following statements is NOT true of the current debate on the origin of birds? 1.关于鸟类起源的争论，下列哪个陈述是错误的?

[A] The opinion that birds were the direct descendants of dinosaurs gives the world a shock. [A]鸟类是恐龙直接后裔，这个观点让世界很震惊。

[B] Palaeontologists have get consensus on the specie’s transition from the land to the sky. [B]古生物学家就该物种从地上到空中的转化这个问题上达成了一致。

[C] Palaeontologists have different opinions on the process of the transition. [C]古生物学家对于转变的过程有不同的观点。

D] The paper in this week’s Current Biology demostrate that the specie moved by hopping before they flied. [D]本周《当今生物》上的论文显示了它们在掌握飞行能力之前是靠跳跃来移动的。

[答案] D

[难度系数] ☆☆

[分析]细节题。A选项，第一段中有提到了这点;B选项，第一段提到许多研究者同意鸟类是恐龙的一个分支，与这点相符;C选项，第一段提到了他们在该问题上有争议;D选项，是靠跳跃实现由地到空的转变，不是移动。因此，答案为D选项。

2. The reason why flight is surprisingly rare is that _____ 2. 为什么飞行动物很少是因为_____

[A] life on earth is diversified. [A] 地球上的生物是多元化的。

[B] many species of this kind were eliminated during evolution. [B]飞行动物的许多物种在进化过程中都灭绝了。

[C] feathers evolved not for a means of transport. [C]鸟类并不是为了移动的方式才进化的。

[D] it is very hard to have such evolution. [D] 发生这样的进化很难。

[答案] D

[难度系数] ☆☆☆☆

[分析] 细节题。根据第二段“Considering the diversity of life on Earth, flight is surprisingly rare. It has evolved only four times: among the insects about 300m years ago, the pterosaurs (230m), the birds (150m) and the bats (50m). That suggests it is a hard trick to pull off”，非行动物只进化了四次，进化是很艰难的过程，因此飞行动物品种少。答案为D选项。

3.The two schools of thought have different opinions on _____ 3. 两派在_____上有不同的观点。

[A] the functions of feathered forearams in transition from ground to sky. [A]长有羽毛的前臂在从地上到空中转变的作用

[B] the location of living place before the animals evolution to birds. [B] 这些动物进化为鸟类之前生活的地方

[C] the development of powered flight. [C] 动力飞行的发展过程

[D] the power provided by either gliding or flapping. [D]力量是由滑翔或者拍动翅膀提供的

[答案] C

[难度系数] ☆☆☆

[分析]细节题。根据第三段和第四段，两派科学家在鸟类的飞行是靠滑行还是靠翅膀提供的升力形成的这一点上有分歧，选项C符合题意。此外B选项比较具有干扰性，文章中提到两种观点认为这些动物在进化为鸟类之前是分别住在地面上和树上，但这只是一个表面的原因，深层次的原因还在C选项。

4. The conclusion of the study carried out by Dr. Glen and Dr. Bennet is that_____ 4.Glen博士和Bennet博士在该研究中得到的最后结论是_____

[A] powered flight developed as feathered forearms provided lift. [A]长有羽毛的前臂提供了升力，从而使得动力飞行发展起来。

[B] flight evolved on the ground before they descend on the trees. [B] 飞行是从地上发展而来的，其发生在它们降落到树上之前。

[C] earliest birds share similar toes with their modern counterparts. [C]飞行是鸟类在到树上之前生活发生的。

[D] earliest flying birds evovled from feathered dinosaurs. [D]最早飞行的鸟类与现代鸟类有着相似的第三脚趾。

[答案] B

[难度系数] ☆☆☆

[分析]细节题。根据第五段和第六段，他们通过研究鸟类脚趾得出结论，鸟类是一开始是在地上生活，后来在到树上生活之前就可以飞翔了，那么它们的飞翔是从地面发展而来的。答案为B选项。C选项具有一定的迷惑性，但是要注意的是“modern counterparts”范围过于广泛，而文中指的是“modern birds that spend most of their time on the ground”，因此该选项错误。

5.Which one of the following statements is NOT true of opinions of Dr. Glen and Dr. Bennet? 5.关于Glen博士和Bennet博士的观点，下列哪个陈述是错误的?

[A]Birds realized the transition from reptile to flight by jumping. [A] 鸟类依靠跳跃实现了从爬行动物到飞行动物的转变。

[B] Dinasaurs are, as a matter of fact, the direct ancestor of birds. [B] 恐龙实际上是鸟类直接的后裔。

[C]Feathers evolves not for the purpose of flight. [C] 鸟类的羽毛不是为了飞行而形成的。

[D] The bird’s behavior is indeed fossilised by their various shape of the third toe. [D] 最早飞行的鸟类的第三个脚趾是轻微弯曲的。

[答案] B

[难度系数] ☆☆☆

[分析] 细节题。B选项，这一点不符合他们的观点，文章中的意思应该是鸟类是恐龙的直接后裔。A选项是正确的，这一点在第一段中就有所提及“But a paper in this week’s Current Biology, by Christopher Glen and Michael Bennett of the University of Queensland, makes a strong case that they did it by jumping”。C选项的表述也是正确的，因为文章提到羽毛的出现甚至在鸟类掌握飞行能力之后，因此不是为了这个目的。D选项的表述是正确的，文章倒数第二段提到“Unfortunately, behaviour does not fossilise, so it looked as though the question might never be answered. But Dr Glen, a palaeobiologist, and Dr Bennett, a biomechanic, think they have worked out how to do so”，进而指出他们采用的方法就是研究鸟类的第三脚趾。因此答案为B选项。

参考译文：

当始祖鸟——一种一半是恐龙一半是鸟类的羽毛动物——的骨架出现在1862年，也就是《物种起源》出版的三年后，鸟类的起源成为古生物学家激烈争论的主题。有人提出它们是兽脚亚目的恐龙(一群两足食肉恐龙，包括异龙、…和暴龙)的直接后裔，这引起了一片哗然。现在，许多研究者同意鸟类实际上是恐龙的一个分支。但是，它们是如何从陆地转到空中生活，在这个问题上还有分歧存在。但是本周《当今生物》发表了昆士兰州Christopher Glen 和Michael Bennett的一篇文章，证明了正是靠跳跃实现了这种转变的。

鉴于陆地上生命的多样性，飞行动物的种类相对是比较少的。飞行动物只进化过四次：三亿年前昆虫类的进化，两亿三千万年前的翼龙，一亿五千万年前的鸟类和五千万年前的蝙蝠。这表明了进化是艰难的历程。大家普遍同意在能够飞行之前，这些动物先有了翅膀。华东发现的化石表明拥有羽毛的动物当时不一定能飞行，即使那些看起来完全像鸟类的也是这样。可能的情况就是羽毛的出现或者是充当隔离层(作用和动物的皮毛一样)，或者是为了好看，而自然选择又将它们转变成运动的工具。

对于接下来的进化，有两派不同看法。一派认为鸟类的直接祖先生长在树上，该派成员认为滑行(今天还有些树栖种类动物依靠这种有控制的坠落来从一棵树转移到另外一棵树上)自然会发展成为飞行。滑行自身也会发展，因为长了羽毛的前臂为其提供了升力。

另外一派的观点是飞行是从地面活动发展而来的。该派的一些研究者认为相当于翅膀的那个部分拍动起来产生的动力让这些动物在捕食时动起来。其他的一些假设还有长了羽毛的前臂有助于动物前行或保持平衡。

不幸的是，动作不能变成化石，因此看起来这个问题可能永远都没有答案了。但是古生物学家Glen博士和生物力学家Bennett博士认为他们已经找出了具体的方案。他们关键的观察报告是有关于现代鸟类第三个脚趾(在行走或爬行的时候这个脚趾承载许多重量)的弯曲度因鸟类生活方式的不同而各有差异。多数时候在树干上爬行鸟类的第三个脚趾非常弯曲，而在树上跳来跳去的鸟类第三个脚趾稍微弯曲，而那些在地上搜索食物的鸟类第三个脚趾是最不弯曲的。

这两位研究者将这些观察结果与中国的类鸟类恐龙和类恐龙鸟类的发现作了比较，他们发现有翅膀的恐龙和最早飞行的鸟类的脚趾与那些大多数时间在地上活动的鸟类相似。换句话说，鸟类在上树生活之前就可以飞翔了。它们不是坠落的天使，而是飞起来的爬行动物。