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
"Migration from Asia" The Asian migration hypothesis is today supported by most of the scientific evidence. The first "hard"
"Migration from Asia" The Asian migration hypothesis is today supported by most of the scientific evidence. The first "hard"
admin
2012-01-14
31
问题
"Migration from Asia"
The Asian migration hypothesis is today supported by most of the scientific evidence. The first "hard" data linking American Indians with Asians appeared in the 1980s with the finding that Indians and northeast Asians share a common and
distinctive
pattern in the arrangement of the teeth. But perhaps the most compelling support for the hypothesis comes from genetic research. Studies comparing the DNA variation of populations around the world consistently demonstrate the close genetic relationship of the two populations, and recently geneticists studying a virus sequestered in the kidneys of all humans found that the strain of virus carried by Navajos and Japanese is nearly identical, while that carried by Europeans and Africans is quite different.
→ The migration could have begun over a land bridge connecting the continents. During the last Ice Age 70,000 to 10,000 years ago, huge glaciers locked up massive volumes of water and sea levels were as much as 300 feet lower than today. Asia and North America were joined by a huge subcontinent of icefree, treeless grassland, 750 miles wide. Geologists have named this area Beringia, from the Bering Straits. Summers there were warm, winters were cold, dry and almost snow-free. This was a perfect environment for large mammals—mammoth and mastodon, bison, horse, reindeer, camel, and saiga (a goatlike antelope). Small bands of Stone Age hunter-gatherers were attracted by these animal populations, which provided them not only with food but with hides for clothing and shelter, dung for fuel, and bones for tools and weapons.
Accompanied by
a husky-like species of dog, hunting bands gradually moved as far east as the Yukon River basin of northern Canada, where field excavations have uncovered the fossilized jawbones of several dogs and bone tools estimated to be about 27,000 years old.
→ Other evidence suggests that the migration from Asia began about 30,000 years ago—around the same time that Japan and Scandinavia were being settled. This evidence is based on blood type. The vast majority of modern Native Americans have type O blood and a few have type A, but almost none have type B. Because modern Asian populations include all three blood types, however, the migrations must have begun before the evolution of type B, which geneticists believe occurred about 30,000 years ago.
By 25,000 years ago human communities were established in western Beringia, which is present-day Alaska.A But access to the south was blocked by a huge glacial sheet covering much of what is today Canada. How did the hunters get over those 2,000 miles of deep ice? The argument is that the climate began to warm with the passing of the Ice Age, and about 13,000 B.C.E. glacial melting created an ice-free corridor along the eastern front range of the Rocky Mountains.B Soon hunters of big game had reached the Great Plains.
→ In the past several years, however, new archaeological finds along the Pacific coast of North and South America have thrown this theory into question.C The most spectacular find, at Monte Verde in southern Chile, produced striking evidence of tool making, house building, rock painting, and human footprints conservatively dated at 12,500 years ago, tong before the highway had been cleared of ice.D Many archaeologists now believe that migrants moved south in boats along a coastal route rather than overland. These people were probably gatherers and fishers rather than hunters of big game.
→ There were two later migrations into North America. About 5000 B.C.E. the Athapascan or Na-Dene people began to settle the forests in the northwestern area of the continent.
Eventually
Athapascan speakers, the ancestors of the Navajos and Apaches, migrated across the Great Plains to the Southwest.
The final migration began about 3000 B.C.E. after Beringia had been submerged, when a maritime hunting people crossed the Bering Straits in small boats.
The Inuits (also known as the Eskimos) colonized the polar coasts of the Arctic, the Yupiks the coast of southwestern Alaska, and the Aleuts the Aleutian Islands.
While scientists debate the timing and mapping of these migrations, many Indian people hold to oral traditions that include a long journey from a distant place of origin to a new homeland.
An introduction for a short summary of the passage appears below. Complete the summary by selecting the THREE answer choices that mention the most important points in the passage. Some sentences do not belong in the summary because they express ideas that are not included in the passage or are minor points from the passage. This question is worth 2 points. There is considerable evidence supporting a theory of multiple migrations from Asia to the Americas.
Answer Choices ______ ______ ______
(A) Ancient stories of migrations from a faraway place are common in the cultures of many Native American nations.
(B) The people who inhabited Monte Verde in southern Chile were a highly evolved culture as evidenced by their tools and homes.
(C) Genetic similarities between Native American peoples and Asians include the arrangement of teeth, viruses, and blood types.
(D) Hunters followed the herds of big game from Beringia south along the Rocky Mountains into what is now called the Great Plains.
(E) Excavations at archaeological sites provide artifacts that can be used to date the various migrations that occurred by land and sea.
(F) The climate began to get warmer and warmer, melting the glacial ice about 13,000 B.C.E.
选项
答案
EDC
解析
summarize the passage. Choice A is a concluding point that is not developed with examples and details. Choice B is a minor point that supports major point E. Choice F is a minor point that supports major point D.
转载请注明原文地址:https://kaotiyun.com/show/AQyO777K
0
托福(TOEFL)
相关试题推荐
TheConceptofChildhoodinWesternCountriesThehistoryofchildhoodhasbeenaheatedtopicinsocialhistorysincetheh
TheConceptofChildhoodinWesternCountriesThehistoryofchildhoodhasbeenaheatedtopicinsocialhistorysincetheh
TheStudyofChimpanzeeCultureA.Afterstudyingthesimilaritiesbetweenchimpanzeesandhumansforyears,researchershav
AccordingtoMrSingh,onwhichthingdomanypeoplemakesuperficialobservations?Whatisbecomingmorewidelyavailabletop
AccordingtoMrSingh,onwhichthingdomanypeoplemakesuperficialobservations?AccordingtoMrSingh,thebiggestproblem
Thievesoftentargetstudents’homesbecausestudents______.Academic______areinsuredupto£5000.
Theprofessorsaysthatsuperhighways______.【28】
TheprofessoralreadyknowssomethingaboutClarefromher______.
WhatisthepurposeofJaneandRick’smeetingwiththetutor?
WhatisthepurposeofJaneandRick’smeetingwiththetutor?
随机试题
按会计工作内容划分,会计制度可以分为
在我国经济运行中,对资源配置起决定性作用的是()。
已知连续函数f(x)满足f(x)=x2+x∫01f(x)dx,则f(x)=().
()是除海洋产业和空间科学技术产业外一切产业项目的支撑基础。
基坑边坡失稳坍塌的实质是边坡土体中的剪应力大于土体的抗剪强度,而土体的抗剪强度决定于土体的内摩擦力和内聚力。因此,凡是能影响土体中剪应力、抗剪强度的都会影响边坡的稳定。下列因素中,不影响边坡稳定的是()。
下列属于市场管理法范围的法是()。
试论法治国家的标志。
下面关于计算机病毒的描述中,正确的是( )。
要使文本框可输入多行文字,要更改的默认选项是
请根据以下各小题的要求设计VisualBasic应用程序(包括界面和代码)。(1)在名称为Form1的窗体上画一个名称为Frame1、标题为“目的地”的框架,在框架中添加三个复选框,名称分别为Check1、Check2、Check3,其标题分别是“上海
最新回复
(
0
)