英语听力文摘 English Digest 208、棘螈

　　Acanthostega
这种生物已经演化出前后肢，但每肢都有８趾。这种生物是从鱼类进化到两栖类的过渡产物。而且，它具有更多的鱼类特征，如有鳃、鳍和只能在水中起作用的感官。伦敦自然历史博物馆的古生物学家珀·阿尔博格说，Acanthostega也许一生很少会离开水。但是化石研究表明、棘螈可以用前肢撑起头部进行呼吸，就像现在的娃娃鱼[大鲵]。

　　It happened in the Devonian Period, about 365 million years ago, what’s known as the Age of Fishes. There were no land vertebrates, only aquatic¹ vertebrates. Then some fish called lobe-finned fish, creatures with bony limb-like fins², slowly evolved into amphibians⁴, the first vertebrates to roam on land.
One of the best pieces of evidence is a fossil called Acanthostega, discovered in Greenland. What’s so remarkable⁵ about it is that it’s a transition fossil. It defies categories. The creature isn’t a fish exactly, nor an amphibian³, but somewhere in between.
It has both lungs and internal gills. It has a tail like a fish, but limbs something like later land creatures. Before the discovery of fossils like Acanthostega, scientists hypothesized that the evolution of limbs was a result of the transition from water to land.
However, Acanthostega’s limbs weren’t capable of supporting the creature’s weight. Although it had hands and feet, it appears that its limbs evolved for use in water in swamps, and only later in evolution were adapted for walking on land.

1 aquatic   

adj.水生的，水栖的

参考例句：

• Aquatic sports include swimming and rowing.水上运动包括游泳和划船。
• We visited an aquatic city in Italy.我们在意大利访问过一个水上城市。

2 fins   

[医]散热片；鱼鳍；飞边；鸭掌

参考例句：

• The level of TNF-α positively correlated with BMI,FPG,HbA1C,TG,FINS and IRI,but not with SBP and DBP. TNF-α水平与BMI、FPG、HbA1C、TG、FINS和IRI呈显著正相关，与SBP、DBP无相关。 来自互联网
• Fins are a feature specific to fish. 鱼鳍是鱼类特有的特征。 来自辞典例句

3 amphibian   

n.两栖动物；水陆两用飞机和车辆

参考例句：

• The frog is an amphibian,which means it can live on land and in water.青蛙属于两栖动物，也就是说它既能生活在陆地上也能生活在水里。
• Amphibian is an important specie in ecosystem and has profound meaning in the ecotoxicology evaluation.两栖类是生态系统中的重要物种，并且对环境毒理评价有着深远意义。

4 amphibians   

两栖动物( amphibian的名词复数 )； 水陆两用车； 水旱两生植物； 水陆两用飞行器

参考例句：

• The skin of amphibians is permeable to water. 两栖动物的皮肤是透水的。
• Two amphibians ferry them out over the sands. 两辆水陆两用车把他们渡过沙滩。

5 remarkable   

adj.显著的，异常的，非凡的，值得注意的

参考例句：

• She has made remarkable headway in her writing skills.她在写作技巧方面有了长足进步。
• These cars are remarkable for the quietness of their engines.这些汽车因发动机没有噪音而不同凡响。