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Amphibians: Transforming Wonders of the Animal Kingdom 两栖类：动物王国的变形金钢

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课文讲解

繁體中文譯本

Have you ever wished you could transform yourself into a completely different kind of being? Or perhaps you’ve dreamed of being able to live and breathe underwater as well as in the open air. For one group of animals, amphibians, these capabilities are no flight of fancy but are actually a way of life.

你是否曾希望自己能化身为一种完全不同的生物？或者你也曾梦想过自己在水里，也能像在陆地上一般地生活与呼吸。对于一种名为「两栖类」动物而言，这些本事并非天方夜谭，而是真实的生存方式。

Frogs, toads, newts, and salamanders are all members of the amphibian family. The world “amphibian,” derived from Greek, literally means “dual life,” referring to the fact that these animals live both in the water and on land. They are generally viewed as one step up the evolutionary ladder from fish. Being cold-blooded, amphibians rely on external sources of energy like sunlight to heat up their bodies, unlike warm-blooded animals such as mammals, which regulate their body temperature internally. This means that amphibians struggle to survive in cold climates and tend to hibernate in the winter months, when their main food sources such as insects are also scarce.

青蛙、蟾蜍、蝾螈和火蜥蜴（或称「真螈」）都是两栖类家族的成员。amphibian一词源自希腊文，字面上解释成「双重生活」，意指这些动物实际上栖息于水中与陆地上。在演化阶段上，牠们普遍被认为较鱼类高一等。由于两栖类属冷血动物，因此需要藉助如阳光的外在能源来使体温升高，不像恒温的哺乳动物，能仰赖体内自行调节体温。这表示两栖类动物在寒冷的气候不易存活，因此往往会在寒冬时期进入冬眠状态，因为这段期间牠们主要的食物来源，例如昆虫，数量也十分稀少。

Another particular characteristic of amphibians is their ability to breathe through their skin. While most species of amphibian possess lungs, salamanders lack these organs altogether and get their supply of oxygen solely through their skin. The life cycle of all amphibians starts underwater, and only once they’ve reached adulthood can they move onto land. This transition comes about through a drastic process of metamorphosis, in which their form completely changes. Each kind of amphibian undergoes this process in its own distinctive way, which only adds to the fascination of these unique creatures.

两栖类另一个不寻常的特征是牠们能透过皮肤呼吸。虽然大多数两栖类动物都具有肺脏，火蜥蜴却完全没有这个器官，而只靠皮肤获取所需的氧气补给。所有两栖类的生命周期起点都始于水中，只有活到成年期后，牠们才能转移到陆地栖息。形成这种转变需要经过剧烈的变态过程，而这些动物的形体也会在过程中完全改变。每一种两栖类动物都会以各自特有的方式经历这个过程，因此让这些独特的生物更加令人着迷。

Vocabulary

单词发音

transform [trænsˋfɔrm] v. 把... 变成

capability [͵kepəˋbɪlətɪ] n. 能力，才能

derive [dɪˋraɪv] v. 起源，由来[（+from）]

literally [ˋlɪtərəlɪ] adv. 照字面地

evolutionary [͵ɛvəˋluʃən͵ɛrɪ] adj. 进化的; 演化的; 演变的

external [ɪkˋstɝnəl] adj. 外面的，外部的

regulate [ˋrɛgjə͵let] v. 调节; 控制﹐管理

internally [ɪnˋtɝnəlɪ] adv. 内部地

scarce [skɛrs] adj. 稀有的，珍贵的

altogether [͵ɔltəˋgɛðɚ] adv. 完全，全然

transition [trænˋzɪʃən] n. 转变﹐变迁

come about 发生; 产生 to take place; happen

drastic [ˋdræstɪk] adj. 激烈的

undergo [͵ʌndɚˋgo] v. 经历；经受

unique [juˋnik] adj. 独一无二的；独特的

More Information

单词发音

amphibian [æmˋfɪbɪən] n. 两栖动物

being [ˋbiɪŋ] n. 生物

flight of fancy 异想天开 an idea which shows a lot of imagination but which is not practical or useful in real situations

toad [tod] n. 蟾蜍，癞蛤蟆

newt [njut] n. 蝾螈

salamander [ˋsælə͵mændɚ] n. 【动】蝾螈; 火蜥蜴

hibernate [ˋhaɪbɚ͵net] n.〔动物〕冬眠

metamorphosis [͵mɛtəˋmɔrfəsɪs] n.【生】变态

distinctive [dɪˋstɪŋktɪv] adj. 有特色的，特殊的

fascination [͵fæsnˋeʃən] n. 令人着迷的事物; 吸引力

课文朗读

课文讲解

Of all the various species of amphibian, frogs are the best-known. We are perhaps all familiar with the frog’s life cycle and its particular type of metamorphosis. Once they’ve hatched from eggs underwater, frogs spend the first stage of their life as tadpoles. Tadpoles live exclusively underwater and breathe through gills, just like fish. Starting off about the size of a pea, they gradually grow, developing first hind legs, then front legs, before losing their gills and eventually growing lungs. Depending on the kind of frog, this tadpole stage can last anywhere from a week to a few months.

在所有两栖类动物中，蛙类是大家熟悉的。我们对蛙类的生命周期与其变态过程应该都不陌生。一旦在水中自卵孵化，蛙类就会以蝌蚪的形态进入生命的第一个阶段。蝌蚪只能在水里存活，牠们和鱼类一样用鳃呼吸。从一粒豆子般大小开始，牠们渐渐成长，先长出后腿再长出前腿，鳃跟着慢慢退化，最后长出肺脏。依蛙的品种不同，蝌蚪阶段可以长达一星期到数月不等。

A number of frog species protect themselves by secreting toxins from their skin. In frogs, bright-colored skin usually serves to advertise this poisonous nature, so the more colorful a frog is, the more wary you should be of touching it! In comparison to multi-colored frogs, toads are rather ugly in appearance. Many people assume that toads are a completely separate type of amphibian, but they are actually just another kind of frog. Apart from their skin being rougher, they have shorted hind legs than frogs, which means they walk rather than hop.

许多蛙类的自卫方式是从皮肤分泌毒液。蛙类鲜艳亮丽的肤色常是用来展示毒性的指标，因此蛙的颜色愈是鲜艳多彩，愈要小心别触碰到牠。比起五颜六色的蛙类，蟾蜍还真是其貌不扬。很多人以为蟾蜍是两栖类动物里完全独立的一种，殊不知牠们其实归属于蛙类。除了皮肤较粗糙外，牠们的后腿也比青蛙短，这意味着牠们行进是用「走」的，而不是用跳的。

Compared to many other animals, amphibians are especially sensitive to changes in their surrounding environment, and as such they are seen as valuable ecological indicators. Their moist skins, through which they breathe, provide little defense against harmful chemicals. Thus, increased pollution had led to a dramatic decline in the worldwide amphibian population in recent years. Unless something is done to clean up our environment, we risk losing these precious animals to extinction.

相较于其他许多动物，两栖类对于所处环境中的改变格外敏感，因此也被视为重要的生态指标。牠们湿润、用以呼吸的皮肤面对有害化学物质时，几乎没有防御的作用。用以呼吸的皮肤面对有害的化学物质时，几乎没有防御的作用。正因为如此，日益严重的环境污染问题已导致近几年来全球蛙类总数锐减。除非我们有所行动，开始净化环境，否则我们很有可能会失去这些宝贵的生物，看着牠们从地球绝迹。

−by David Vickers

Vocabulary

单词发音

stage [stedʒ] n.（进展的）阶段；时期

exclusively [ɪkˋsklusɪvlɪ] adv. 专门地，特定地

depend on 取决于, 随…而定

poisonous [ˋpɔɪznəs] adj. 有毒的；有害的

wary [ˋwɛrɪ] adj. 〔人〕小心翼翼的﹐谨慎的

in comparison to/with  与…比较, 与…相比

assume [əˋsjum] v. 以为；假定为；（想当然地）认为

compared to 与…相比，跟…相比(=in comparison to/with)

sensitive [ˋsɛnsətɪv] adj. 敏感的

ecological [͵ɛkəˋlɑdʒɪkəl] adj. 生态（学）的

indicator [ˋɪndə͵ketɚ] n. 指标

moist [mɔɪst] adj. 潮湿的

defense [dɪˋfɛns] n. 防御，防护

decline [dɪˋklaɪn] n. 下降；减少

extinction [ɪkˋstɪŋkʃən] n. 灭绝﹐绝种

More Information

单词发音

hatch [hætʃ] v.（蛋）孵化

tadpole [ˋtæd͵pol] n.【动】蝌蚪

gill [gɪl] n.（鱼）鳃

start off 开始; 出发 to be or make the first step in an activity; initiate

pea [pi] n.【植】豌豆

secrete [sɪˋkrit] v.【生理】分泌

toxin [ˋtɑksɪn] n.【生化】毒素，毒质

dramatic [drəˋmætɪk] adj. 突如其来的; 急剧的

Reading Questions

1. Which of the following is NOT a feature of amphibians?

A. They can breathe through their skin.

B. They can control their body temperature.

C. They spend the first part of their life underwater.

D. They often eat insects.

2. What does the article mention about the process of metamorphosis?

A. It always takes place on land.

B. It only happens to amphibians.

C. It is longest for frogs.

D. It differs for each amphibian species.

3. According to the article, how are toads different from frogs?

A. Their skin is more colorful.

B. They are larger.

C. They are unable to hop.

D. They are poisonous.

4. Which of the following is implied in the article?

A. Most people don’t know what a tadpole is.

B. Colorful frogs make ideal pets.

C. We should be worried about the number of amphibians.

D. Amphibians have a damaging impact on the environment.

Life Cycle of a Frog

Answer