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科学美国人60秒 SSS 鲸鱼在失去牙齿后进化出鲸须

时间:2019-09-29 02:21:16

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(单词翻译)

This is Scientific American — 60-Second Science. I'm Annie Sneed.

这里是科学美国人——60秒科学。我是安妮·斯尼德。

Baleen1 whales are the gentle giants of the sea. Despite their colossal2 size, they feed on tiny creatures such as krill and zooplankton. That's because these whales, instead of teeth, have bristle-like structures in their mouth—baleen—which filters out small critters from big gulps3 of water. But the ancestors of baleen whales had a very different diet. 

须鲸是海洋中温和的庞然大物。它们虽然体型庞大,但却以磷虾和浮游动物等微小生物为食。这是因为须鲸没有牙齿,它们的口中是鬃毛状结构的鲸须,这使须鲸可以吞一大口水然后把小生物过滤出来。但是须鲸祖先的饮食习惯与这些后代的差别非常大。

"So, the oldest whales that we know, these are the ancestors not just of the great whales like the Blue Whale and the Humpback Whale, but also of all of the dolphins in the sea today, they had fairly big teeth."

“我们已知的最古老鲸鱼,其后代不仅包括蓝鲸和座头鲸等大型鲸鱼,还包括今天海洋中的所有海豚,这些古老鲸鱼的牙齿相当大。”

Felix Marx, a postdoctoral research fellow at the Royal Belgian Institute of Natural Sciences.

比利时皇家自然科学研究所的博士后研究员费利克斯·马克思说到。

"And the most common idea is that they ate relatively4 large fish, and for some of the biggest ones... there are some studies that looked specifically of the wear of those teeth at the microscopic5 level, and they seem to suggest that they ate almost anything that they came across. The point is that they had big teeth that were really sharp, and that were even, relative to the size of their jaws6, were relatively large, so they were really predators7."

“最常见的观点是,这些最古老鲸鱼以相对较大的鱼为食,对于一些体型最大的鲸鱼,用显微镜专门观察其牙齿磨损程度的研究显示,它们似乎会吃掉遇到的所有东西。关键是它们拥有又大又非常锋利的牙齿,它们的牙齿与下颚相比也是相当大的,因此它们是真正的捕食性动物。”

So where did baleen come from? Marx and his colleague Ewan Fordyce set out to answer this question. They analyzed8 the mouth of a 34-million-year-old fossil of one of the earliest baleen whales, called Llanocetus denticrenatus, found in Antarctica. And they concluded that Llanocetus had sharp teeth and large gums—but no baleen.

那它们的鲸须是从何而来的呢?马克思和同事着手解答这个问题。他们对南极发现的一块3400万年前的须鲸化石进行了研究,并分析了它的口腔情况,这是其中一种最古老鲸鱼“刻齿拉诺鲸”的化石。他们得出的结论是,刻齿拉诺鲸拥有锋利的牙齿和巨大的牙龈,但是没有鲸须。

Their findings argue against one of the ideas about how baleen evolved—that at some point whales had both teeth and baleen. "Llanocetus is the first and it's the only specimen9, the only species, the only archaic10 whale, that makes a very clear case that, no, this coexistence of baleen and teeth, as it was just imagined basically...based on what modern whales looked like, didn't work. It didn't exist in that sense." The finding is in the journal Current Biology.

这一发现驳斥了有关鲸须演化方式的一种观点,该观点认为在某个时刻,鲸鱼同时拥有牙齿和鲸须。“刻齿拉诺鲸是能提供证明的首个且唯一的样本,是唯一的物种,唯一的古老鲸鱼,刻齿拉诺鲸能明确证明鲸须和牙齿并未共存过,人们当初基于现代鲸鱼的样子进行想象的情况并不属实。从这种意义上说,这种共生并不存在。”这项研究结果发表在《当代生物学》期刊上。

So how did some whales go from chomping11 predators to filter feeders? "Baleen is effectively an outgrowth of the gums, and that probably only happened once the teeth had already been lost or maybe had been severely12 reduced. So we suggest this intermediate phase where you start with teeth and biting, then you start sucking your food, then because you suck in small things, you start to develop a filter and eventually you become a proper filter feeder."

那一些鲸鱼是如何从咀嚼性捕食动物变成滤食动物的呢?“实际上,鲸须是牙龈的产物,可能只有在已经失去牙齿或牙齿严重脱落时才会发生。因此我们认为,这是一种中间阶段,在这种情况下,鲸鱼一开始用牙齿咬食,然后开始吸食食物,之后因为吸入了小生物,鲸鱼就开始进化出过滤器官,最终成为完全的滤食动物。”

Thanks for listening for Scientific American — 60-Second Science. I'm Annie Sneed.

谢谢大家收听科学美国人——60秒科学。我是安妮·斯尼德。


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1 baleen ZPey2     
n.鲸须
参考例句:
  • Other baleen whales have splash guards too,but not like this.一些须鲸物种头顶也有护住喷水孔的构造,但并不长成这样。
  • Baleen whales often appear in this region. Be careful!这一带经常有须鲸出没,要注意安全啊。
2 colossal sbwyJ     
adj.异常的,庞大的
参考例句:
  • There has been a colossal waste of public money.一直存在巨大的公款浪费。
  • Some of the tall buildings in that city are colossal.那座城市里的一些高层建筑很庞大。
3 gulps e43037bffa62a52065f6c7f91e4ef158     
n.一大口(尤指液体)( gulp的名词复数 )v.狼吞虎咽地吃,吞咽( gulp的第三人称单数 );大口地吸(气);哽住
参考例句:
  • He often gulps down a sob. 他经常忍气吞声地生活。 来自辞典例句
  • JERRY: Why don't you make a point with your own doctor? (George gulps) What's wrong? 杰瑞:你为啥不对你自个儿的医生表明立场?有啥问题吗? 来自互联网
4 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。
5 microscopic nDrxq     
adj.微小的,细微的,极小的,显微的
参考例句:
  • It's impossible to read his microscopic handwriting.不可能看清他那极小的书写字迹。
  • A plant's lungs are the microscopic pores in its leaves.植物的肺就是其叶片上微细的气孔。
6 jaws cq9zZq     
n.口部;嘴
参考例句:
  • The antelope could not escape the crocodile's gaping jaws. 那只羚羊无法从鱷鱼张开的大口中逃脱。
  • The scored jaws of a vise help it bite the work. 台钳上有刻痕的虎钳牙帮助它紧咬住工件。
7 predators 48b965855934a5395e409c1112d94f63     
n.食肉动物( predator的名词复数 );奴役他人者(尤指在财务或性关系方面)
参考例句:
  • birds and their earthbound predators 鸟和地面上捕食它们的动物
  • The eyes of predators are highly sensitive to the slightest movement. 捕食性动物的眼睛能感觉到最细小的动静。 来自《简明英汉词典》
8 analyzed 483f1acae53789fbee273a644fdcda80     
v.分析( analyze的过去式和过去分词 );分解;解释;对…进行心理分析
参考例句:
  • The doctors analyzed the blood sample for anemia. 医生们分析了贫血的血样。 来自《简明英汉词典》
  • The young man did not analyze the process of his captivation and enrapturement, for love to him was a mystery and could not be analyzed. 这年轻人没有分析自己蛊惑著迷的过程,因为对他来说,爱是个不可分析的迷。 来自《简明英汉词典》
9 specimen Xvtwm     
n.样本,标本
参考例句:
  • You'll need tweezers to hold up the specimen.你要用镊子来夹这标本。
  • This specimen is richly variegated in colour.这件标本上有很多颜色。
10 archaic 4Nyyd     
adj.(语言、词汇等)古代的,已不通用的
参考例句:
  • The company does some things in archaic ways,such as not using computers for bookkeeping.这个公司有些做法陈旧,如记账不使用电脑。
  • Shaanxi is one of the Chinese archaic civilized origins which has a long history.陕西省是中国古代文明发祥之一,有悠久的历史。
11 chomping 77141b3117534187e56113c95cb76b7f     
v.切齿,格格地咬牙,咬响牙齿( chomp的现在分词 )
参考例句:
  • Elizabeth and Lawrence are chomping at the bit to go on vacation. 伊莉莎白和劳伦斯迫不及待要去度假了。 来自互联网
  • She was chomping away on a bagel. 她在嘎蹦嘎嘣地啃着一个硬面包圈。 来自互联网
12 severely SiCzmk     
adv.严格地;严厉地;非常恶劣地
参考例句:
  • He was severely criticized and removed from his post.他受到了严厉的批评并且被撤了职。
  • He is severely put down for his careless work.他因工作上的粗心大意而受到了严厉的批评。

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