资源描述：
《2013理工A职称英语新增.doc》由会员上传分享，免费在线阅读，更多相关内容在应用文档-天天文库。
1、阅读理解第四十八篇ResearchersDiscoverWhyHumansBeganWalkingUprightMostofuswalkandcarryitemsinourhandseveryday.Theseareseeminglysimpleactivitiesthatthemajorityofusdon'tquestion.Butaninternationalteamofresearchers,includingDr.RichmondfromGW'sColumbianCollegeofArtsandScienceshavediscoveredthathumanwalkinguprigh
2、t,mayhaveoriginatedmillionsofyearsagoasanadaptationtocarryingscarce,high-qualityresources.TheteamofresearchersfromtheU.S.,England,JapanandPortugalinvestigatedthebehaviorofmodern-daychimpanzeesastheycompetedforfoodresources,inanefforttounderstandwhatecologiealsettingswouldleadalargeape-onethatresemb
3、lesthe6million-yearoldancestorwesharedincommonwithlivingchimpanzees-towalkontwolegs."Thesechimpanzeesprovideamodeloftheecologicalconditionsunderwhichourearliestancestorsmighthavebegunwalkingontwolegs,"saidDr.Richmond.Theresearchfindingssuggestthatchimpanzeesswitchtomovingontwolimbsinsteadoffourinsi
4、tuationswheretheyneedtomonopolizearesource.Standingontwolegsallowsthemtocarrymuchmoreatonetimebecauseitfreesuptheirhands.Overtime,intenseburstsofbipedalactivitymayhaveledtoanatomicalchangesthatinturnbecamethesubjectofnaturalselectionwherecompetitionforfoodorotherresourceswasstrong.Twostudieswerecon
5、ductedbytheteaminGuinea,ThefirststudywasconductedbytheteaminKyotoUniversity's"outdoorlaboratory"inanaturalclearinginBossouForest.Researchersallowedthewildchimpanzeesaccesstodifferentcombinationsoftwodifferenttypesofnut—theoilpalmnut,whichisnaturallywidelyavailable,andthecoulanut,whichisnot.Thechimp
6、anzees"behaviorwasmonitoredinthreesituations:(a)whenonlyoilpalmnutswereavailable,(b)whenasmallnumberofcoulanutswereavailable,and(c)wbemcoulanutsweretbemajorityavailableresource.Whentherarecoulanutswereavailableonlyinsmallnumbers,thechimpanzeestransportedmoreatonetime.Similarly,whencoulanutswerethem
7、ajorityresource,thechimpanzeesignoredtheoilpalmnutsaltogether.Thechimpanzeesregardedthecoulanutsasamorehighly-prizedresourceandcompetedforthemmoreintensely.Insuchhigh-competitionsettings,thefrequencyofcases
