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
Why does the professor mention fossils?
Why does the professor mention fossils?
admin
2012-01-14
24
问题
Why does the professor mention fossils?
[Professor] (mate)
OK. Let’s get to work, class. Q12 Today we’re--we’re going to be talking about an extremely important idea in geology: continental drift. The slow movement and reconfiguration of the continents on Earth’s surface.
It all began pretty early...well, I mean, back in the sixteenth century. Q14(C) Scholars had observed that, um, that the contours of the continents on opposite sides of the Atlantic Ocean, um, bore some resemblance to one another.They wondered if maybe there was some way the continents had "drifted" apart over time...but since there wasn’t any kind of feasible theory that could explain how huge landmasses like continents could move at all--much less move across the entire region now occupied by the Atlantic Ocean--um, since there weren’t any good theories to account for that, um, it just remained an unsolved mystery.
That is, until 1912, when a German scientist called Alfred Wegener proposed his theory of "continental drift." Q13 Wegener discovered that not only were the coastlines on either side of the Atlantic Ocean similar, the fossils contained in their crusts were too. Theories at the time tried to account for the similarity between fossils by suggesting that a land bridge once existed between the continents, but, to Wegener, this just didn’t seem like enough evidence. He couldn’t get it out of his head that the continents might have once been joined. He gathered a great deal of evidence to support his belief and eventually went public with it. In 1912, he announced his theory of continental drift to...well, we’ll call it an incredibly unreceptive scientific community. The thing is, even with all his evidence, um, Wegener failed to convince his peers of the validity of his theory, because he couldn’t come up with a plausible mechanism for continental drift, an explanation of how continents might move. So...all throughout the 1920s and 1930s, scientists ridiculed the idea of continental drift, calling it unscientific. It simply didn’t fit into their set of beliefs about how the world worked, and so they rejected it, ignoring the evidence that supported it instead of looking for new reasons to explain how it might occur. Q16 Little did they know, within the next 40 years...the theory of continental drift would become universally accepted.
What changed? What caused this thoroughly despised theory to gain such popularity? Well, as you might have guessed, the change was the result of a new explanation for the mechanism behind continental drift. I’ll tell you how it happened. Um, in the 1960s, the notion of seafloor spreading arose...suggesting that the seafloor actually, um, grew--or spread out--from places on the ocean floor. And as the ocean floor expanded, the continents were carried along. Soon, experts were constructing a picture of a dynamic planet, one gradually transformed by large-scale movements of pieces of its rocky crust. Q14(A) Their new theory, known as plate tectonics, explained what the theory of continental drift never did--how continents could move around on Earth’s surface. And here’s how. The theory of plate tectonics sees the surface of our planet as an outer shell, which covers a softer layer beneath. This--this lower layer, which is called the asthenosphere, uh, it’s pretty solid...but on a geologic timescale, it basically, um, flows. Q17 I know this notion may be a little strange to you, but I don’t want to get into it right now because it’s really a topic for another lecture...so just try to imagine that because of the properties of the asthenosphere, pieces of the Earth’s outer shell--called "tectonic plates"--can move around over really, really long periods of time. Q15(A) In some places, two plates are slowly moving away from each other, and these spots are known as divergent boundaries. Q15(B) in ether places, two plates are colliding, usually causing one of the plates to submerge. These zones are referred to as convergent boundaries.
So...with all this new information, scientists were forced to reexamine the idea of continental drift. Considered in the new light of plate tectonics, it seemed quite plausible. Plate tectonics basically just updated the theory of continental drift...and many concepts that were rejected when Wegener put them forward are now universally accepted as true.
选项
A、To describe the evidence Wegener used to develop his theory.
B、To suggest that Wegener borrowed ideas from earlier scientists.
C、To explain how Wegener first became interested in geology.
D、To show why most scientists ridiculed Wegener’s theory.
答案
A
解析
转载请注明原文地址:https://kaotiyun.com/show/y5yO777K
0
托福(TOEFL)
相关试题推荐
Completetheflowchartbelow.ChooseNOMORETHANTWOWORDSfromthepassageforeachanswer.Writeyouranswersinboxes10-13
TheHistoryoftheGuitarTheword’guitar’wasbroughtintoEnglishasanadaptationoftheSpanishword’guitarra,’whichwas,
ChooseTHREElettersA-G.Writeyouranswersinboxes37-39onyouranswersheet.WhichTHREEofthefollowingarefeatu
Lookatthefollowingdescriptionsandthelistofcompaniesbelow.Matcheachdescriptionwiththecorrectcompany,A-F.
CompanyInnovationA.InashabbyofficeindowntownManhattan,agroupof30AI(artificialintelligence)programmersfrom
【31】Thespeakersuggestsostrichfarmsareprofitablebecause______.
Theprofessorsaysthatsuperhighways______.【29】
TheprofessoralreadyknowssomethingaboutClarefromher______.
Manyorganisationswillpayforthecostofavolunteer’s______toAfrica.Jobslastingoverayeargenerallyoffera______
Whichattitudeisassociatedwiththefollowingpeopleduringtheconversation?ChooseSIXanswersfromtheboxandwritetheco
随机试题
个人生命周期中维持期的主要特征有()。Ⅰ.对应年龄为45~54岁Ⅱ.家庭形态表现为子女上小学、中学Ⅲ.主要理财活动为收入增加、筹退休金Ⅳ.保险计划为养老险、投资型保险
我国第一部纪传体通史是【】
某孕妇,末次月经的时间为2008年2月6日,其预产期应该是
按照发行主体分类,债券可分为()。
社会工作者小康正在对无业青年进行研究。他经常到网吧、游戏厅、台球室等场所与这些青年聊天,逐渐被他们接纳为自己人。小康也在这个过程中了解到几个无业青年的个人生活史,切身感受到他们的困惑迷茫。小康采用的研究方式是()。
王老师在讲授物种分类时,为了让学生更深刻地理解同科属物种的相似性,她利用春游的机会带领学生去当地的自然博物馆参观,有效弥补了学生对物种分类的认知欠缺。王老师采用的教学方法是()。
A、B、C、D、E、F六个小朋友做游戏,每轮游戏都按照下面的箭头方向把原来手里的玩具传给另外一个小朋友:A→F,B→D,C→E,D→B,E→A,F→C。开始时,A、B、C、D、E、F拿着各自的玩具,传递完10轮时,有几个小朋友又拿到了自己的玩具?
B-ISDN为了实现网络传输的高速率与低延迟采用了
下列4项中,不属于计算机病毒特征的是
•Readthetextbelowaboutdifferentkindsofconsumergoods.•ChoosethebestwordtofilleachgapfromA,B,CorDontheo
最新回复
(
0
)