托福阅读tpo45R-1 原文+译文+题目+答案+背景知识.pdf

托福阅读tpo45R-1TheBeringiaLandscape

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原文

TheBeringiaLandscape

①Duringthepeakofthelasticeage,northeastAsia(Siberia)and

AlaskawereconnectedbyabroadlandmasscalledtheBeringLand

Bridge.ThislandbridgeexistedbecausesomuchofEarth’swaterwas

frozeninthegreaticesheetsthatsealevelswereover100meters

lowerthantheyaretoday.Between25,000and10,000yearsago,

Siberia,theBeringLandBridge,andAlaskasharedmanyenvironmental

characteristics.Theseincludedacommonmammalianfaunaoflarge

mammals,acommonfloracomposedofbroadgrasslandsaswellas

wind-sweptdunesandtundra,andacommonclimatewithcold,dry

wintersandsomewhatwarmersummers.Therecognitionthatmany

aspectsofthemodernfloraandfaunawerepresentonbothsidesof

1

theBeringSeaasremnantsoftheice-agelandscapeledtothisregion

beingnamedBeringia.

②ItisthroughBeringiathatsmallgroupsoflargemammalhunters,

slowlyexpandingtheirhuntingterritories,eventuallycolonizedNorth

andSouthAmerica.Onthisarchaeologistsgenerallyagree,butthatis

wheretheagreementstops.Onebroadareaofdisagreementin

explainingthepeoplingoftheAmericasisthedomainof

paleoecologists,butitiscriticaltounderstandinghumanhistory:what

wasBeringialike?

③TheBeringianlandscapewasverydifferentfromwhatitistoday.

Broad,windsweptvalleys;glaciatedmountains;sparsevegetation;and

lessmoisturecreatedaratherforbiddinglandmass.Thislandmass

supportedherdsofnow-extinctspeciesofmammoth,bison,andhorse

andsomewhatmodernversionsofcaribou,muskox,elk,andsaiga

antelope.Thesegrazerssupportedinturnanumberofimpressive

carnivores,includingthegiantshort-facedbear,thesaber-toothcat,

andalargespeciesoflion.

④