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SSS 2008-05-07

时间:2010-05-14 01:07来源:互联网 提供网友:0922013129   字体: [ ]
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    (单词翻译:双击或拖选)

This is Scientific American's 60-Second Science,I am Steve Mirsky.Got a minute?

It’s accepted that a large meteor impact 65 million years ago was responsible for the mass extinction1 of the dinosaurs2.  Which opened up niches3 for birds and mammals.  But last week at an evolution conference at The Rockefeller University in New York City, New Zealand biologist David Penny questioned whether the dinosaurs might not have already been on their way out. Penny concentrated on fossils of pterodactyls and birds. Turns out that the average wing spans of pterodactyls had been getting steadily4 larger before the big impact. By the time the meteor hit, pterodactyls still making a mark in the fossil record had wingspans well over 30 feet.  Meanwhile, it looks like the Cretaceous version of shore birds were becoming relatively5 common, based on fossil findings.  So perhaps the smaller pterodactyls had disappeared because the new kid in town, birds, were out-competing them. Penny’s view was certainly not uniformly accepted by other meeting attendees. But it’s an interesting question, whether the meteor might have been not the first strike, but the last straw.

Thanks for the minute,for Scientific American's 60-Second Science,I'm Steve Mirsky.


点击收听单词发音收听单词发音  

1 extinction sPwzP     
n.熄灭,消亡,消灭,灭绝,绝种
参考例句:
  • The plant is now in danger of extinction.这种植物现在有绝种的危险。
  • The island's way of life is doomed to extinction.这个岛上的生活方式注定要消失。
2 dinosaurs 87f9c39b9e3f358174d58a584c2727b4     
n.恐龙( dinosaur的名词复数 );守旧落伍的人,过时落后的东西
参考例句:
  • The brontosaurus was one of the largest of all dinosaurs. 雷龙是所有恐龙中最大的一种。 来自《简明英汉词典》
  • Dinosaurs have been extinct for millions of years. 恐龙绝种已有几百万年了。 来自《简明英汉词典》
3 niches 8500e82896dd104177b4cfd5842b1a09     
壁龛( niche的名词复数 ); 合适的位置[工作等]; (产品的)商机; 生态位(一个生物所占据的生境的最小单位)
参考例句:
  • Some larvae extend the galleries to form niches. 许多幼虫将坑道延伸扩大成壁龛。
  • In his view differences in adaptation are insufficient to create niches commensurate in number and kind. 按照他的观点,适应的差异不足以在数量上和种类上形成同量的小生境。
4 steadily Qukw6     
adv.稳定地;不变地;持续地
参考例句:
  • The scope of man's use of natural resources will steadily grow.人类利用自然资源的广度将日益扩大。
  • Our educational reform was steadily led onto the correct path.我们的教学改革慢慢上轨道了。
5 relatively bkqzS3     
adv.比较...地,相对地
参考例句:
  • The rabbit is a relatively recent introduction in Australia.兔子是相对较新引入澳大利亚的物种。
  • The operation was relatively painless.手术相对来说不痛。
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TAG标签:   SSS  dinosaur
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