科学美国人60秒 SSS 2014-09-22
时间：2018-12-24 作者：英语课 分类：2014年Scientific American(九)月
英语课
Sixty-six million years ago, the meteorite 1, a rock over six miles wide, slammed into the earth and you know what happened next, the dinos disappeared. but Benjemin Blunder, a planty ecologist at the University of Arizona, says ," consider the picture for a moment."
You have to think not only about the charismatic animals which are walking on the planet but also all the resources on which those animals are depending.
Say, for example, vegetation. Blunder has been giving those overshadowed impact victims their due. After all, more than half the planet's species in temporary North America periched along with the dinosours. And the type of plants that thrived after the impact were different as well. Blunder and his colleagues studied thousands of fossile leaves from North Dokotar, spanning about a million years both before and after the impact. They measured the leaf mass per area, a proxy 2 for how much energy a plant invests in its leaves, and density 3 vein 4 s, which indicates how fast growing the leaf is. Sturdy, slow-growing leaves tend to be ever-greens, whereas the flimsy, fast-growing leaves are hall marks of decidous plants. Turns out that after the impact the fossile records have more deciduously looking leaves, suggesting that fast-growing, more adaptable 6 seasonal 7 plants beat out the competition after the big hit. The study appears in the journal" Plus Biology". And it kind of made me wonder if we have overlooked another theory for why the dions died out. Maybe they just didn't care for the taste of the deciduous 5 leaves.
1 meteorite
n.陨石；流星
- The meteorite in Jilin Exhibition Hall is believed to be the largest in the world.吉林展览馆的陨石被认为是世界上最大的。
- The famous Murchison meteorite smashed into the Australian ground in 1969.1969年著名的默奇森陨石轰然坠落在澳大利亚。
2 proxy
n.代理权，代表权；（对代理人的）委托书；代理人
- You may appoint a proxy to vote for you.你可以委托他人代你投票。
- We enclose a form of proxy for use at the Annual General Meeting.我们附上委任年度大会代表的表格。
3 density
n.密集，密度，浓度
- The population density of that country is 685 per square mile.那个国家的人口密度为每平方英里685人。
- The region has a very high population density.该地区的人口密度很高。
4 vein
n.血管，静脉；叶脉，纹理；情绪；vt.使成脉络
- The girl is not in the vein for singing today.那女孩今天没有心情唱歌。
- The doctor injects glucose into the patient's vein.医生把葡萄糖注射入病人的静脉。
5 deciduous
adj.非永久的；短暂的；脱落的；落叶的
- Overgrown deciduous shrubs can be cut back at this time of year.过于繁茂的落叶灌木可以在每年的这个时候修剪。
- Deciduous trees shed their leaves in autumn.落叶树木在秋天落叶。