托福阅读笔记。说到托福阅读备考，TPO是必不可少的备考神器，通过TPO练习来更好的适应阅读考试的节奏。本文小编带来的是TPO31 Speciation in Geographically Isolated Populations的学习笔记，希望能够与正在备考的大家一起进步。
TPO31 Speciation in Geographically Isolated Populations
文章题材：生物学科——物种隔离
常见词汇：
previously ['pri:vju:sli] adv. 先前，在此之前
addition [ə'diʃən] n. 增加，附加物，加法
glacier ['glæsjə] n. 冰河，冰川
evolutionary [.i:və'lu:ʃnəri] adj. 进化的，发展的，演变的
claim [kleim] n. 要求，要求权;主张，断言，声称;要求物
proceed [prə'si:d] vi. 继续进行，开始，着手
experienced [iks'piəriənst] adj. 有经验的
promote [prə'məut] vt. 促进，提升，升迁; 发起; 促销
gene [dʒi:n] n. 基因
barrier ['bæriə] n. 界线，屏障，栅栏，障碍物
易错题解析：
Paragraph 2:Allopatric speciation may be the main speciation route. This should not be surprising, since allopatry is pretty common. In general, the subpopulations of most species are separated from each other by some measurable distance. So even under normal situations the gene flow among the subpopulations is more of an intermittent trickle than a steady stream. In addition, barriers can rapidly arise and shut off the trickle. For example, in the 1800s a monstrous earthquake changed the course of the Mississippi River, a large river flowing in the central part of the United States of America. The change separated populations of insects now living along opposite shore, completely cutting off gene flow between them.
5. In paragraph 2,why does the author mention that some insect populations were separated from each other by a change in the course of Mississippi River caused by an earthquake?
A. To make the point that some kind of physical barrier separates the subpopulations of most species.
B. To support the claim that the condition of allopatry can sometimes arise in a short time.
C. To provide an example of a situation in which gene flow among the subpopulations of a species happens at a slow rate.
D. To explain why insects living along opposite shores of the Mississippi River are very different from each other.
题型：推论题。答案是(B)
解析：For example后面就是题目中的内容，那么也就是说作者用此作为例子来支持前 面的观点。而前面的观点是 barriers也有可能突然发生，然后截断了这种trickle。所以对应的是B。
Paragraph 4：Allopatric speciation can also be brought by the imperceptibly slow but colossal movements of the tectonic plates that make up Earth’s surface. About 5 million years ago such geologic movements created the land bridge between North America and South America that we call the Isthmus of Panama. The formation of the isthmus had important consequences for global patterns of ocean water flow. While previously the gap between the continents had allowed a free flow of water, now the isthmus presented a barrier that divided the Atlantic Ocean from the Pacific Ocean. This division set the stage for allopatric speciation among populations of fishes and other marine species.
8. According to paragraph 4, which of the following is true of the geologic movements that brought about the Isthmus of Panama?
A.The movements brought populations of certain fishes and marine organisms into contact with one another for the first time.
B.The movements transferred populations of fishes and other marine animals between the Pacific and Atlantic Oceans.
C.The movements created conditions that allowed water to flow more freely between the Pacific and Atlantic Oceans.
D.The movements created conditions for the formation of new species of fishes and other marine animals.
题型：事实信息题。答案是(D)
解析：根据Isthmus of Panama定位。从About开始。本段的最后一句说了isthmus of Panama带来的结果，对应了D选项。
以上就是小编带来的托福阅读笔记之TPO31 Speciation in Geographically Isolated Populations,希望能够和备考的大家一起学习。更多托福考试资讯请关注前程百利。
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