美途达旭日升2000字考古.docx

WhatpromptedearlyhumanstoleaveAfricaforthefirsttimeDiscussiononthereasonsandevidenceforthefirsttimethatearlyhumansleftAfricaIntroductionThispaperdiscussesthetopicof"nofactorcanexplainthefirsttimethatearlyhumansleftAfrica".Earlyhumansareancienthumansintheearlystageofhumanevolutionfromapestohumans,includingthehumanoidanimalsatthistime.ThefirstdeparturefromAfricareferstothefirstoutwardmigrationofearlyhumanbeingsfromtheAfricancontinent.ThispaperdiscussestheevidenceandreasonsofearlyhumanleavingAfricaforthefirsttimefromthreeaspects:thetestimonyprovidedbyhumanfossils,theevidenceprovidedbyclimatechangeandthetestimonyprovidedbyhumangeneticmappinganalysis.Thispaperbelievesthattheestablishmentoftheperiodofhumanfossilsandhumanremainsbyarchaeologistscancorroborateeachotherwiththeclimateanalysisandhumangenemapextensionofpaleoclimatology,andcanprovethatearlyhumansleftAfricaforthefirsttimeduetoclimatechangeanddeteriorationoflivingenvironment,andspreadtotheEurasiancontinentandotherterritories.1. DirectevidencefromhumanfossilsHumanfossilsareallthathumanancestorsleftintheworld,andarealsoimportantevidencetorevealthepathandcauseofhumanmigration.In1924,archaeologistsfoundtheoldestancienthumanfossilinalimestonecaveinDrimolen,nearJohannesburg,SouthAfrica,andnameditAustralopithecusAfricanus.Amongmorethan900ancienthumanremains,oneofthemwas3millionyearsago(Dennell,Roebroeks,2005).In1990,researchersfoundtheearliestancienthumanfossilsattheDemanisisiteinGeorgia,whichwereearlierthanthoseinAfrica.Theseskullfossilsandbonefossilshavebeenprovedthatancienthumansatthattimewereveryshort,only1.5meterstall,andthebraincapacitywasonlyonethirdofthatofmodernhumans(Agust,Lordkipanidze,2011).TheemergenceoftheDemanianancientsextendedtheearliesttimeofhumanexistenceinAsiato1.8millionyearsago.Later,archaeologistsfoundtheearliestEuropeanfossilsatthearchaeologicalsiteofAtapulcainSpain,whicharehumantoothbonesdatingmorethan1.4millionyearsago(Forster,Matsumura,2005).Accordingtothetimejudgmentofarchaeologistsonthefossilsofancientapesandhumans,noearlierhumanfossilremainshavebeenfoundonthecontinentoutsideAfrica.Fromtheevidenceprovidedbyancienthumanfossils,asearlyas2.5MaBPto3.0MaBPthereweresignsofancienthumanandhumanlifeinAfrica.TheearliestsurvivaltimeofhumanintheSouthCaucasuswas1.7MaBPto1.8MaBP,whiletheevidenceoftheearliesthumanlifeinWesternEuropecouldbeextendedto1.4MaBP(Derricourt,2005).Accordingtothetimejudgmentofarchaeologistsonthefossilsofancientapesandhumans,noearlierhumanfossilremainshavebeenfoundonthecontinentoutsideAfrica.TheevidenceprovidedbyancienthumanfossilsshowsthattheancienthumanfossilsinthesouthernCaucasusandwesternEuropearemoreadvancedthanthoseofAfricanancienthumansintermsofbraincapacity,heightandotheraspects,althoughtheseancienthumansarestillverybackwardcomparedwiththebraincapacity,heightandphysicalabilityofmodernhumans.ThetimepointoftheappearanceofancienthumanfossilscaneffectivelyprovethatAfricansfirstappearedancienthumansandbecametheearliestancestorsofmankind.StonesandotherearlyinstrumentsunearthedfromarchaeologicalsitescanalsoprovethatancienthumansandhumanoidanimalslivinginAfricagatheredandmigratedduringtheprocessofforagingandhunting.ThereisnoevidenceofearlierhumanandanimalproliferationinothercontinentsexceptAfrica(Balter,Gibbons,2020).Atthesametime,alargenumberoffossilsfromtheSouthAfricanGardenfoundintheEastAfricanRiftValley,theeastbankofLakeTurnerinKenya,andtheTanzanianValleyhaveprovedthattheyhavetheabilitytowalkuprightandusesimpletools.TheseevidencescanprovethatearlyhumanbeingshavetheabilitytomigrateandliveingroupsforlongdistancesinAfrica.Itcan'thelpthinkingthatearlyhumanbeingssetoutfromtheAfricancontinentandcrossedthedesertnorthward,enteredtheCaucasusfromSuez,andfurthermigratedtoIndiaandWesternEurope.ThestoneaxeandothertoolsunearthedinGeorgiaevenprovedthatearlyhumanshadbeenverycruelandviciousintheprocessofleavingtheAfricancontinentandmigratingtotheMiddleEast.Theyevendirectlycompetedwithwildcarnivoresforfood.Therefore,thechronologicalsequence,evolutionarycharacteristicsandthecharacteristicsoftoolsusedbyearlyhumansexcavatedbyarchaeologistsfromallovertheworldcansupporteachotherandsupporttheviewthatearlyhumansleftAfricaforthefirsttime.2. ClimatetransformationmakesmankindleaveAfricaClimatechangeforcedearlyhumanstoleaveAfricaandbegintomigratebychangingthelivingenvironmentofhumans.AccordingtotheresearchofQuaternarypaleoclimatologists,theglobalpaleoclimatehasundergonesignificantadjustmentbetween2.5and2.8MaBRAtthistime,theearthenteredtheQuaternaryIceAge(Thomas,Burrough,2012).MostofEuropeandNorthAmericabegantofreezerapidly,andmostofthelandinthenorthernhemispherewascoveredbyglaciers.TheScandinavianGlacierCenter,SiberianGlacierCenterandGreenlandGlacierCenterinthenorthernhemispherebegantoextendtothesouth(Timmermann,Friedrich,2016).Theexpansionofglaciersinthenorthernhemispherehasmadetheclimatemovesouthward.Atthesametime,theclimateoftheAfricancontinentbegantobecomeunusuallydry,andtheairhumidityandprecipitationonthecontinentdecreasedrapidly.T