首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
A、Dinosaurs. B、Mammoths. C、Saber-toothed cats. D、Tropical frogs. D
A、Dinosaurs. B、Mammoths. C、Saber-toothed cats. D、Tropical frogs. D
admin
2018-01-01
29
问题
Good afternoon, folks. In today’s lecture, we talk about the dinosaurs. One of the greatest mysteries about the dinosaurs is why they died out suddenly at the end of the Cretaceous Period 65 million years ago. A number of theories have been suggested to account for this mass extinction. The most popular theory is that a comet or meteorite hit the Earth and exploded with a terrific force, throwing up a dust cloud that blocked out the sun. Suddenly, it gets cold everywhere, and everyone dies. Nevertheless, I think this theory doesn’t work. Because it completely ignores most of what is happening on land. If you want to study dinosaurs and understand them, you’ve got to think about frogs and turtles and salamanders and mammals, too. You can’t take dinosaurs out of context. All the big animals were dinosaurs; that’s true. But most animals aren’t big. Go to the Amazon rain forest, or even a forest in New Jersey, and you’ll find that most of the animals there are small. If you exploded a nuclear bomb right now over Brazil blocking the sunlight and chilling the Amazon rain forest, who would die first? The big deer and jaguars or the little frogs? Frogs should die first, because they are the most delicate creatures in any ecosystem; their blood is in intimate contact with the water they live in. Also, a tropical frog exposed to a chill can’t hibernate, so it dies. A big animal, such as a deer or elephant, can stand a major chill and can move to another area. But have you ever heard of frog extinctions at the end of the Cretaceous Period? No. That’s because no frogs died out. No turtles or salamanders died out. None of these delicate animals, with no defense at all against a sudden chill, died out. But dinosaurs—the biggest, most active animals that should take weeks to kill—did die. This is true of every major extinction that has ever hit the Earth. Not so long ago, there were woolly mammoths and saber-toothed cats in Chicago. There were beavers the size of Buicks all over North America. They disappeared about 10,000 years ago So you may ask: what caused those mass extinctions? Well, it is very hard to come up with a theory that will kill big animals and leave little ones alone. The one thing that would do it is disease. This is a theory developed by American paleontologist Henry Osborn in 1899. He pointed out that when big animals travel, they’ll spread dozens of diseases and disrupt the ecology. Whenever we humans have brought animals from one continent to another, bad things happen. Someone brought starlings from England to North America, and we have a starling problem. Introduce foreign animals and they run amuck. They do not have natural predators and also they spread disease. Whenever there was a mass extinction on land, there were land bridges connecting the continents and big animals moving across them. During most of the history of life, broad oceans have separated the continents. But, periodically, those ocean barriers get drained away and animals can move. Big animals travel very easily. Give an elephant a land bridge and the population will spread at least 1,600 kilometers in two years. Little animals don’t move nearly as fast. It takes a long time for the population of a snake, salamander, or frog to spread. Osborn pointed out that if big animals move across land bridges and start spreading, you’re going to have extinctions caused by disease or disruptions to the ecosystem. There is no way to prevent it. So I like Osborn’s theory. It’s based in ecological reality. We know that foreign animals always cause disaster.
Question No. 16 What is the most popular theory about the dinosaurs’ extinction?
Question No. 17 Why are frogs the most delicate creatures in an ecosystem?
Question No. 18 What is the theory developed by American paleontologist Henry Osborn in 1899?
Question No. 19 Which of the following is NOT regarded as a major extinction of species?
Question No. 20 According to the speaker, what is essential in the spread of diseases by big animals?
选项
A、Dinosaurs.
B、Mammoths.
C、Saber-toothed cats.
D、Tropical frogs.
答案
D
解析
转载请注明原文地址:https://kaotiyun.com/show/clSO777K
本试题收录于:
NAETI高级口译笔试题库外语翻译证书(NAETI)分类
0
NAETI高级口译笔试
外语翻译证书(NAETI)
相关试题推荐
下面你将听到的是一段在英中贸协年会上的讲话。女士们、先生们:我非常高兴能利用英中贸协年会的机会向英国工商界朋友们致以诚挚的问候。多年来,英中贸协一直关心和支持中英关系发展,是堪称两国友好交流的桥梁和互利合作的纽带。在此,我谨对英中贸协及诸位长期
当前经济全球化不断发展,科学技术突飞猛进,为新世纪全球经济和社会发展提供了前所未有的技术条件。尤其是信息通信技术的发展,深刻地改变着人们的经济社会和文化生活方式。一方面,信息化为经济发展和社会进步提供了难得的数字机遇,而另一方面它也给我们带来了各
A、Pricessoar.B、Debtrepaymentbecomesmoredifficult.C、Consumersareencouragedtowaitforevenlowerprices.D、Thecostof
Economicsendowsprospectivebusinessmenwithquiteafewdesirablequalities,suchasintelligenceandintuition.
ThepurposeoftheAmericancourtsystemistoprotecttherightsofthepeople.AccordingtoAmericanlaw,ifsomeoneisaccuse
A、ThemanisnotsatisfiedwiththespeedMissJenkinstypes.B、ThemanishesitatingwhethertoacceptMissJenkinsornot.C、T
A、Designingfashionitemsforseveralcompanies.B、Modelingforaworld-famousItaliancompany.C、WorkingasanemployeeforFer
A、Sheturnedoffthelights.B、Shefoundherlockhere.C、Theclasswascancelled.D、Theclasshasfinished.D
Californiaisalandofvarietyandcontrast.Almosteverytypeofphysicallandfeature,sortofarcticicefieldsandtropical
A、Itisasuitablemediumfortropicalthemes.B、Itisnotsuitableforoldtimethemes.C、Thecolorchangesfrombrowntopurpl
随机试题
人体的触电方式分()两种。
血液透析常见的并发症除外()
大便出血,同时伴有黏液,呈持续性,肛门坠胀.多为
某药材多分枝,常弯曲,集聚成簇,形如鸡爪。与该药材名称相同,弯曲呈钩状,多为单枝,较细小的是()。
关于阴道前庭的解剖结构正确的是
不属于专利权主体的是下列的( )。
选择债券指数化投资的原因不包括()。
下列事项中,可能表明内部控制存在重大缺陷的有()。
2020年9月3日,中共中央、国务院、中央军委在北京人民大会堂举行座谈会,纪念中国人民抗日战争暨世界反法西斯战争胜利75周年。习近平出席座谈会并发表重要讲话强调,中国人民在抗日战争的壮阔进程中孕育出伟大抗战精神,向世界展示了天下兴亡、匹夫有责的爱国情怀,视
我们刚刚吃过午饭。
最新回复
(
0
)