60秒科学:鲸鱼祖先统治海洋多久？

《科学杂志》上的一项研究表明，硬骨滤食性鱼类用了10亿年的进化时间，占据了须鲸类现在的生态龛。另一项研究表明，鲸类的多样化取决于其食用的微生物类型。

Sometimes scientific discoveries are hidden in museum specimen¹ drawers and old journal articles. In two studies in the journal Science, researchers who went through the stuff in institutional attics² offer new insights into the development and diversity of filter-feeding whales—and the fish that first occupied that ecological³ niche⁴.

It had been thought that mammoth⁵, filter-feeding fish—which swam through the water with a gaping⁶, open mouth, collecting tiny marine⁷ creatures—only lived fleetingly⁸ before whales took their place in the food chain.

But a research team [led by Matt Friedman, University of Oxford] decided⁹ to take a closer look at museum fossils of bony, pre-historic fish that had either been misclassified or ignored. They also reexamined previous studies.The investigators¹⁰ now say that these fish filter-feeders lived from about 170 to 65 million years ago, a healthy stretch in which to pioneer and perfect the niche.

In a related study, scientists [Felix Marx, University of Otago, New Zealand and Mark Uhen, George Mason University] show that when filter-feeding whales took over from bony fish, their diversity was linked to the diversity of their dinner—the tiny creatures at the very bottom of the food chain –tiny algae known as diatoms
 

1 specimen   

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。

2 attics   

n. 阁楼

参考例句：

• They leave unwanted objects in drawers, cupboards and attics. 他们把暂时不需要的东西放在抽屉里、壁橱中和搁楼上。
• He rummaged busily in the attics of European literature, bringing to light much of interest. 他在欧洲文学的阁楼里忙着翻箱倒笼，找到了不少有趣的东西。

3 ecological   

adj.生态的，生态学的

参考例句：

• The region has been declared an ecological disaster zone.这个地区已经宣布为生态灾难区。
• Each animal has its ecological niche.每种动物都有自己的生态位.

4 niche   

n.壁龛；合适的职务(环境、位置等)

参考例句：

• Madeleine placed it carefully in the rocky niche. 玛德琳小心翼翼地把它放在岩石壁龛里。
• The really talented among women would always make their own niche.妇女中真正有才能的人总是各得其所。

5 mammoth   

n.长毛象；adj.长毛象似的，巨大的

参考例句：

• You can only undertake mammoth changes if the finances are there.资金到位的情况下方可进行重大变革。
• Building the new railroad will be a mammoth job.修建那条新铁路将是一项巨大工程。

6 gaping   

adj.口的；张口的；敞口的；多洞穴的v.目瞪口呆地凝视( gape的现在分词 )；张开，张大

参考例句：

• Ahead of them was a gaping abyss. 他们前面是一个巨大的深渊。
• 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。 来自《简明英汉词典》

7 marine   

adj.海的；海生的；航海的；海事的；n.水兵

参考例句：

• Marine creatures are those which live in the sea. 海洋生物是生存在海里的生物。
• When the war broke out,he volunteered for the Marine Corps.战争爆发时，他自愿参加了海军陆战队。

8 fleetingly   

adv.飞快地，疾驰地

参考例句：

• The quarks and gluons indeed break out of confinement and behave collectively, if only fleetingly. 夸克与胶子确实打破牢笼而表现出集体行为，虽然这种状态转瞬即逝。 来自互联网

9 decided   

adj.决定了的，坚决的；明显的，明确的

参考例句：

• This gave them a decided advantage over their opponents.这使他们比对手具有明显的优势。
• There is a decided difference between British and Chinese way of greeting.英国人和中国人打招呼的方式有很明显的区别。

10 investigators   

n.调查者，审查者( investigator的名词复数 )

参考例句：

• This memo could be the smoking gun that investigators have been looking for. 这份备忘录可能是调查人员一直在寻找的证据。
• The team consisted of six investigators and two secretaries. 这个团队由六个调查人员和两个秘书组成。 来自《简明英汉词典》