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
2018-07-24
57
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 ice-free, 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 long 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 Beringa had been sub merged, 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.
The phrase Accompanied by in the passage is closest in meaning to
选项
A、Found with
B、Joined by
C、Threatened by
D、Detoured with
答案
B
解析
In this passage, the phrase Joined by is a synonym for "Accompanied by." Context comes from the word part, "company."
转载请注明原文地址:https://kaotiyun.com/show/53fO777K
0
托福(TOEFL)
相关试题推荐
Completetheflowchartbelow.ChooseSIXanswersfromtheboxandwritethecorrectletter,A-G,nexttoquestions11-16.Aair
Completetheflowchartbelow.WriteNOMORETHANTWOWORDSforeachanswer.ExpertiseincreativewritingB
Completetheflowchartbelow.WriteNOMORETHANTWOWORDSforeachanswer.ExpertiseincreativewritingB
Completethesentencesbelow.WriteNOMORETHANTWOWORDSforeachanswer.Thedreamtimecanbeexperiencedbeneaththe______
Whichattitudeisassociatedwiththefollowingpeopleduringtheconversation?ChooseSIXanswersfromtheboxandwritetheco
Completethenotesbelow.WriteNOMORETHANTWOWORDSforeachanswer.CLIMATEANDARCHITECTURECasesandexamplesarefrompra
Completethenotesbelow.WriteNOMORETHANTWOWORDSforeachanswer.CLIMATEANDARCHITECTURECasesandexamplesarefrompra
A、Therightsofprivatebusinessownersshouldbeprotected.B、Thegovernmentshouldn’tinterfereinprivatebusiness.C、Politic
"MigrationfromAsia"TheAsianmigrationhypothesisistodaysupportedbymostofthescientificevidence.Thefirst"hard"
"ConquestbyPatents"→Patentsareaformofintellectualpropertyrightsoftentoutedasameanstogive’incentiveandrew
随机试题
十五络脉指十二经脉之别络,以及
鼓胀的病位在
A.《本草纲目》B.《重修政和经史证类备急本草》C.《神农本草经》D.《温疫论》E.《黄帝内经》最早的一部中医典籍
如图所示,折射率为n2,厚度为e的透明介质薄膜的上方和下方的介质的折射率为n1和n3,已知:n1<n2>n3。若用波长为λ的单色平行光垂直入射到该薄膜上,则从薄膜的上、下两表面反射的光束①和②的光程差是()。
理财规划合同宜采用( )形式。
位于市区的某电子设备生产企业,主要生产电脑显示器.拥有固定资产原值6500万元,其中房产原值4000万元,2008年发生以下业务:(1)销售显示器给某销售公司,开具增值税专用发票,按销售合同约定取得不含税销售额7000万元;购进原材料,取得增值税专用发票
在上完一节课后,老师对今天所学知识进行模拟小测验,这属于()。
“大有大成,小有小成”是()教学原则具体运用的结果。
素质教育的首要任务是()。
Manypeopleliketotravel.Theproblemisgettingyourpettothe(1)______.Inrecentyears,transportingpetsonflightshasg
最新回复
(
0
)