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EarlyHominids species,whichwasnamedasHomodenisova.WhilethesehumanswereevolvinginEuropeandAsia,evolutioninEastAfricadidnotstop.Thecradleofhumanitycontinued to nurture numerous species, such as Homorudolfensis, ‘Man fromLake Rudolf’, Homo ergaster, ‘Working Man’, and eventually our own species,which we’veimmodestlynamedHomosapiens,‘Wise Man’(Harari,2014). TRENDSINHUMANEVOLUTION:UNDERSTANINGPREMODERNHUMANS Asyoucansee,themiddlePleistocenehomininsareaverydiversegroup,broadlydispersed through time and space. There is considerable variation among them,and it’s not easy to get a clear evolutionary picture. We know that regionalpopulationsweresmallandfrequentlyisolated,andmanyofthemprobablydiedoutandleftnodescendants.Soit’samistaketoseean“ancestor”ineveryfossilfind. Still, as a group, these Middle Pleistocene pre-moderns do reveal somegeneral trends. In many ways, for example, it seems that they were transitionalbetween the hominins that came before them (H. erectus) and the ones thatfollowed them (modern H. sapiens). It’s not a stretch to say that all the MiddlePleistocene pre-moderns derived from H. erectus forebears and that some ofthem, in turn, were probably ancestors of the earliest fully modern humans(Jurmainetal., 2011). Paleoanthropologistsarecertainlyconcernedwithsuchbroadgeneralitiesasthese,but they also want to focus on meaningful anatomical, environmental, andbehavioraldetailsaswellasunderlyingprocesses.Sotheyconsidertheregionalvariability displayed by particular fossil samples as significant-but just howsignificant is up for debate. In addition, increasingly sophisticated theoreticalapproaches are being used to better understand the processes that shaped theevolutionoflaterHomoatbothmacroevolutionaryandmicroevolutionarylevels.Paleoanthropologistswhoadvocateanextremelumpingapproachrecognizeonlyone species for all the premodern humans. These premoderns are classified asHomosapiens and are thus lumped together with modern humans, althoughthey’re partly distinguished by such terminology as “archaic H. sapiens.” Aswe’venoted,thisdegreeoflumpingisnolongersupportedbymostresearchers.Alternatively, a second, less extreme view postulates modest species diversityand labels the earlier premoderns as H. heidelbergensis. At the other end of thespectrum,moreenthusiasticpaleontologicalsplittershaveidentifiedatleasttwo(or more) species distinct from H. sapiens. The most important of these are H.heidelbergensisand H.neanderthalensis(Jurmainetal.,2011). Allthesehomininsarecloselyrelatedtoeachotheraswellastomodernhumans.Andeveryoneagreesthatonlysomeofthefossil samplesrepresentpopulationsthat left descendants. Where paleoanthropologists disagree is when they startdiscussing which hominins are the most likely to be closely related to laterhominins. The grouping of hominins into evolutionary clusters (clades) andassigning of different names to them is a reflection of differing interpretations-and, more fundamentally, of somewhat differing philosophies(Jurmain et al.,2011). ThehomininsthatbestillustratetheseissuesaretheNeanderthals.Fortunately,they’realsothebestknownrepresentedbydozensofwell-preservedindividuals. 50 NeanderthalsarecertainlyverycloselyrelatedtomodernH.sapiens.Theyare physicallyandbehaviorallydistinctfrombothancientandfullymodernhumans.Neanderthals are not a fully separate biological species from modern people.WecanviewNeanderthalsasadistinctivesidebranchoflaterhomininevolution.It is not unreasonable to say that Neanderthals were likely an incipient species.Given enough time and enough isolation, they likely would have separatedcompletely from their modern human contemporaries. The new DNA evidencesuggeststhattheywerewellontheirway,verylikelyapproachingfullspeciationfrom Homo sapiens. However, some fossil and archaeological data continue tosuggestthatNeanderthalsperhapsneverquitegotthatfar.Theirfate,inasense,wasdecidedforthemasmoresuccessfulcompetitorsexpandedintoNeanderthalhabitats.Thesehighlysuccessfulhomininswerefullymodernhumans(Jurmainetal.,2011). Historyof Human Evolution HOMINIZATION DuringMioceneepoch,theglobalclimaticchangesleadtothecoldenvironmenton the earth which induced open terrestrial biomes and reduction of tropicalforest.Overtime,thesizeoftropicalforestdecreasedandbrokeupintomosaicwhere patches of forest were interspersed with savannah grassland. As forestshrank,thetraditionalapefoodavailableontreesbecamescarce.Inresponsetothese ecological change primates came down from the trees and inhabited theterrestrial ecosystem (Havilandet al., 2011). They used to spend more time ontheground.Thisnecessitatedforagingfoodonthegroundsuchasseeds,grasses,rootsandothers.Eventuallytheybecameadaptedtoexposedterrestrialenvironment. In due course of time evolution lead to biped locomotion, largebrain size, tool making behaviour, development of language and culture, whicharesignificantindefiningwhatmakesahominidahominid.Theseevolutionaryprocesseswhichleadtothedevelopmentofhumancharacteristicsdistinguishedfromprimatesareknownashominization.Thus,hominizationcouldbeunderstoodasamultidimensionalmorphogenesisarisingfromtheinterplayof 51 EarlyHominids ecological,cerebral,socio-culturalandgeneticfactors.Theprocessofhominization was intensified by the prolonged infancy and childhood whichdemand affective ties between generation and associated potential for culturallearning(Wulf,2012).Now,wehumansorHomosapiensareaculture-bearing,upright-walking species that lives on the ground and evolved between 100,000and200,000yearsago(EncyclopediaBritannica). In the present unit we will provide an overview of the evolutionary changeswhich lead totheemergenceof human featuresdistinguishedfrom primates. Bipedalism Ofallextantprimates,humansaretheonlyobligatebipeds(Harcourt-SmithandAiello,2004).Theerectbipedalposturewepossesshavebeenevolvedfromanknuckle-walkingancestor(Richmondetal.,2001).Thoughsomeoftheprimatescan assume bipedal posture but only for a short duration that is when peeringover tall grass or carrying objects in the hands. Chimpanzee and Gorilla arecapable of much longer periods of bipedality but when on the ground they arenormallyquadrupedalandinknucklewalkingstance.Truebipedalismisrepresentedonlybyhumans(Swindler,1996).Overthelastseveralmillionyearsofevolution,thesecharacteristichavedevelopedindependentlyatdifferentrates.Thesepatterns,inwhichphysiologicalandbehaviouralsystemsevolveatdifferentrates iscalled mosaic evolution (Jurmainet al.,2014). Bipedalism inhumans istheoutcome ofalargenumber ofadaptivemusculoskeletaltraitswhichcompletely transformedhumanlineage.Suchadaptivetraitshaveresultedfromlongtermmodificationsinthevertebralcolumn,thepelvis,thelower limb andthe foot. EvidencesforBipedalism:Thefundamentaldistinctionbetweenusandourclosestrelativesisnotourlanguage,notourculture,notowntechnology.Itis 52 thatwestandupright,withourlowerlimbsforsupportandlocomotionandour upperlimbsfreefromthosefunctions”,saidRichardE.Leakey,apalaeontologist.Paleoanthropologists mark the divergence between apes and hominids with theadaptation of bipedalism five to six million years ago. However, the process ofbecoming a fully efficient biped took much longer and was not complete untilHomo erectus at 1.8 million years ago (Friedman, 2006). Hominid footprintspreserved in the ash fall of a volcanic eruption some 3.5-3.8 million years ago(duringPlioceneperiod)atLaetolisiteinnorthernTanzaniarepresenttheearliestevidence of bipedalism in human evolution. These footprints were discoveredby Mary Leakey in the late 1970s and are believed to be the imprints ofAustralopithecus afarensis, the earliest known hominid group (evolutionarylineagethatalsoincludesourspeciesHomosapiens;Jurmainetal.,2014) Early researchers hypothesized that brain enlargement was the first hallmark ofthe hominid lineage setting them apart from the apes. In 1828, embryologistKarl Ernst von Baer wrote, “Upright posture is only the consequence of thehigher development of the brain....... all differences between men and otheranimals depend upon construction of the brain” (Gould, 1977). However, thediscovery of early hominid fossils exhibiting ape-sized brains and bipedally-adaptedmorphologyshowedthatbipedalismevolvedafewmillionyearsbeforebrain. In1924, ananatomist Raymond Dart discovered the skull ofAustralopithecine fossil, known as the Taung Child, from South Africa. Thisspecimen belonged to the species Australopithecus africanus.The brain sizewassimilartomodernapesbuttheforamenmagnumpositionedforwardindicatedthat it held its head erect and walked upright. This was demonstrated mostimpressively by the finding of nearly complete fossilized skeleton of Lucy(female),amemberofthespeciesAustralopithecusafarensisbyDonaldJohanson,at Hadar, Ethiopia in 1974. The limb and pelvic fossils provided indisputableevidenceofbipedalityanderectposture.Shehadtheanatomyofabiped,includingabroadpelvisandthighbonesthatangledintowardtheknees,whichbringsthefeet inlinewiththebody’scenterofgravityandcreatesstabilitywhilewalking(Wayman,2012). AnatomicalChanges:Haveyouevernoticedthemovementofyourlimbswhenyouwalk?Wemaintainthebalanceononelegwhentheotherlegswings.Bothfeetaresimultaneouslyonthegroundonlyabout25percentofthetimeandthisfigure becomesevensmallerasspeedof thelocomotionincreases. Thus,maintainingastablecenterofbalanceduringuprightwalkingnecessitatedmanydrasticstructural andfunctional changesparticularlyinthe limbsand pelvis. Shorteningandbroadeningofpelvisandstabilizationofweighttransmission Quadraped have vertically elongated hip bones positioned parallel to eachother along the sides of the lower portion of vertebra. In contrast, homininilliumofhipbonebecamecomparativelyshorterandbroader.Remodellingof pelvis lead to basin shaped structure that support abdominal organs andallows transmission of weight from lower back to hip joint during erectposture (Jurmain, 2012). This increased the distance between thorax andpelvisandfreedthelumbarregionfromwithinthepelvis.ThismodificationallowedlowerbacktomoveforagreaterdistancethanGreatApe(Lovejoy,2005).Thealterationinpelvisalsobroughtthesacroiliacandhipjointsintocloseproximity,reducingforcetransmissionstresstotheilium(AielloandDean,1990).Modificationsofthepelvisi.eexpandedandanteriorlyprojectingiliacbladewithrespecttotheischiumrepositionedthegluteal Historyof Human Evolution 53 EarlyHominids musculature.Inquadrupeds,itispositionedtothesideofhipboneand function to pull the thigh to the side and away from the body while inhumansitispositionedbehindthehip,whichalongwithhamstringsmusclehelp to extend and pull thigh to rear during walking or running (Jurmainetal., 2014) The fossils of Australopithecus afarensis also known as ‘Lucy’ presents ashift towards the human pelvic condition. This shift facilitated adaptationstothebipedallocomotionincludingmanychangessuchasabroadsacrum,awidenedinter-acetabulardistanceandpronouncedlateraliliacflare(Berge,1994). Fig 1. Pelvis bone with the attachment of muscleSource:Jurmainetal.,2014 54 ChimpanzeeGluteus medius –Hipextensor Human Gluteusmedius Abductsthehiplaterally Stabilises the hip duringlocomotion i.e. stops thepelvis dropping whilst wearestoodononeleg. Historyof Human Evolution forwardmovement Hamstringsgroup Hip extensor whenapplyingagroundforce Kneeflexorwhenlegisraised Hamstringsgroup Hipextensorwhenstanding Bringsthelegsandtorsointolinefromabentforwardposition Kneeflexorwhenlegisraised Deceleratesthekneejustbeforeheel-strikewhenrunning Fig2.FunctionoflimbmusclesSource:http://anthroanatomica.blogspot.in/2013_04_01_archive.html Repositioningofforamenmagnumforward,theopeningatthebaseofskullfromwhichspinalcordemerges. In comparison to other primates, humans possess foramen magnum inanteriorpositionwhichisconsideredasanadaptationformaintainingbalanceoftheheadatopthecervicalvertebralcolumn.Incontrast,Quadrupedswithposteriorlypositionedforamenmagnumrequirewell-developedmusculatureandligamentstobeartheweightofhead.Theuniquepositionoftheforamenmagnumassociatedwithbipedalismanderectposture,inhumanscomparedwithotherlivingorthogradeprimates,suggestthatforamenmagnumpositionmay be used to identify bipedal adaptations in fossil hominins (Jurmain,2012;Lovejoy,2005;AielloandDean,1990;Jurmainetal.,2014;Berge, 1994;RussoandKirk,2013). Human B)Chimpanzee Fig3.PositionofforamenmagnumSource:AdaptedfromJurmainetal.,2012 Additionofcurves(backward-thoracic,forward-lumbar)inspinalcordtotransmittheweightoftheupperbodytohipsinupperinanuprightposition. 55 EarlyHominids Tomaintainthebipedalpostureundertheeffectsofgravity,aneffective transmissionoftheupperbodyweightisrequired.Thistransmissionisdonefrom the trunk, through the pelvic girdle to the lower limbs.The adaptivechangeinrelationtoweighttransmissionincludedaposteriorconcavityofthevertebralcolumninthelumbarregionandconvexityinthoracicregion.The curvature also helps to absorb the force exerted during walking orrunning and allows flexion and extension of the trunk (Jamie Kendrick,2014). Lack of such characteristic flexibility in extant primates restrictstheirlowerbackmobility.Italsoallowedcentreofmasstoliecentrallyandverticallyabovethehipswhichconsequentlybalancethebodywhilestridingin upright posture. The spinous process of more than half of the vertebraepointcaudally.Thischangeinorientationisrelatedtotherearrangementofthemusclesofthebackwhichallowerectpostureoftrunkregion(Buttner-Janusch,1969). Chimpanzee australopith modernhuman Pelvis sideview (frontfacingto theright) soiaticnotch iliacblade acetabulum(hipjoint) soiaticnotch iliac blade acetabulum(hipjoint) soiaticnotch iliacblade acetabulum(hipjoint) ischium ischium ischium Pelvisfrontview sacrum ilium sacrum ilium sacrum ilium Widestance grasping feet narrowstance Walkingfeet Fig 4. Anatomical changes in pelvisSource:www.encylopediabritinnica.com Lengtheningofhindlimband largebicondylar angle Humanshavecomparativelylongerlowerlimbsthanextantprimateswhichcontributetolongerstridelength.Thefemoralbicondylarangledistinguishesbipedalhumansfromquadrupedalapesasitalignsthebody’smidlinewiththedistalendofthefemur,kneeandlowerleg.Thishelpedinbody’scentreof mass to lie directly over the stance leg while walking (Aiello and Dean,1990).Thisanglerangesbetween8to11°inhumanswhileitaverages1-2°inAfricanapes.Aprominentinter-trochantericline,glutealtuberosityandaraised lineaaspera enhanced attachments for muscles and ligaments inhumansthat alsoassistedtomaintain uprightposture. 56 a)Modernhuman b)Australopithecus c)Chimpanzees Fig 5. Femoral- Bicondylar anglesSource:AdaptedfromShefelbineetal.,2002 Structuralchangesinfoot Throughoutevolution,primateshaveretainedanarboreallifestyle,andfootshape characterised by a grasping (opposable) hallux and elongated distalsegments. Acquisition of habitual bipedalism involved various anatomicalchanges(D’AoutandAerts,2008): Historyof Human Evolution Fig 7.Movementoffoot 57 Source:www.emedicinehealth.com Source:www.wikipedia.com EarlyHominids Astabilizedplantararchwhichallowthefoottosupportbodyweight, lossofhallux(knownasbigtoeinhuman)opposabilityanditsalignmentparalleltootherphalanges, theproportionsofthefootwithrelativelyshortphalanges,makingitamoreeffectivelever, alongandwelldevelopedcalcanealtubercle(heelbone)withalongAchillestendonwhich impactposturalorientation, Uprightposturefreedthearmstocarryvariousobjects(including offspring). ChariesDarwinemphasizedthisview,particularly relating totools andweapons;however, evidence of stone tools is foundmuchlaterintherecordthanfirstevidenceofbipedalism. Bipedalismallowedcarryingofweapons,more accurate throwing of certain weapons,and imporvedlong-distancewalking. Systematichuntingisnowthoughtnottohavebeenpracticedunitlaftertheoriginofbipedalhominins(seeissue, Chapter 12). Feedingonseedsandnutsoccurredwhilestandingupright. Modelinitiallydrawnfromanalogywithgeladababoons(see text). Vertical posture exposes less of the body todirect sun; increased distance from groundfacilitates cooling by increased exposure tobreezes. Worksbestforanimalsactivemiddayonsavanna; moreover, adaptation to bipedalismmayhaveinitiallyoccurredinwoodlands,noton savanna. Standingupprovidedbetterviewofsurrounding countryside (view of potentialpredatorsaswell asothergroupmembers). Bhevaiourseenoccasionallyinterrestrialprimates(e.g.baboons):probablyacontributingfactor,but unlikely as"prime mover". Coveringlongdistanceswasmoreefficientfora biped than for a quadruped (during huntingorforaging);mechanicalreconstructionsshowthatbipedalwalkingislessenergeticallycostlythan quadrupedalism (this is not the case forbipedalrunning). Samedifficultiesaswithfuntingexplanation;long-distanceforagingongroundalsoappearsunlikelyadaptationin earliesthominins. Malescarriedbackresourcestodependentfemalesandyoung. Monogamousbondsuggested;however,mostskeletal data appear to falsify this part of thehypothesis(seetext). Fig8.Factorsinfluencingevolutionofbipedalism 58 Source:AdaptedfromLewiset al.,2010) Talocruraljoint(anklejoint)actassynovialhingejointpermittingdorsi-flexionand plantarflexion movement of the foot. Bipedalismfreedtheforearmforuseandmanufacturingoftools.Inbipeds,lessportion of body is directly exposed to sun which provides thermo-regulatoryadvantageandaidincoolingofthebody.Moreover,asgreaterportionofbodyisawayfromground.Itpreventswarmingofbodybyheatradiationfromtheground.Bipedal stance provided wider view of the surroundings and early spotting ofprey.Theybecameefficientincoveringlongdistanceandhunting.Pelvicchangesassociatedwithbipedalismresultedinsmallerbirthcanal.Evolutionsleadtothebirth of an infant at a stage when the head can fit through the birth canal, butinducedprolongedgrowthanddependencyperiods.Thisconsequentlyencouragemale to guard female with depend infants and development of affectionaterelationship(Jurmainetal.,2012). OpposableThumbandManualDexterity A diminutive thumb with long and curved fingers is typical characteristics of aprimatehand(Midlo,1934).Incontrast,thehumanhandhasanopposablethumbcombinedwithfingersthathaveshortenedandstraightened.Althoughapesalsosharethetraitofopposabilityofthumbbutitisonlytheabilityofhumanstogripobjectsfirmlyinordertomanipulatethem(MarzkeandMarzke,2000).Humanthumbalsodisplaysagreaterdegreeofmobilityincomparisontootherprimateswhichmakesitunique anddistinctive(Young,2003). Figure9a Figure9b Chimpanzeehand Human handAmodelforthehandofthe hominidancestor Source:AdaptedfromNapier, 1956 Thediscoveryoffossilhandbonesassignedtoa1.8-million-year-oldspecimenhumanancestorHomohabilisatOlduvaiGorgeintheearly60’s,hasputforthageneralagreementthattheanatomicalreconstructionofthehandduringhumanevolutionwassomehowlinkedwithtoolbehaviour.Thisapproachisconsistentwithevidencethatearlyhominidbipedalbehaviourwouldhave‘freedthehands’forgreateruseoftools(Young,2003). Historyof Human Evolution 59 EarlyHominids Duringtheprolongedperiodofevolution,thehandunderwentprofoundchangesthatadapteditforgraspingobjectsinamannerthatallowsgrippingwithstrengthsufficient to withstand a violent impact and precise control of release. Napieridentified them as ‘power’ and ‘precision’ grips. In the power grip, the objectmay be held in a clamp formed by the partly flexed fingers and the palm wherecounter pressure being applied by the thumb lying more or less in the plane ofthe palm while in the precision grip, the object may be pinched between theflexoraspectsofthefingersandtheopposingthumb (Napier,1956). Fig10.aPowergrip Fig.10.b Precision gripSource:Adaptedfrom Napier,1956 Infigure10.a,thehandgrippingthehammerstonedisplaysthepowergrip.Thisgrip controls the striking point and absorbs the shock. Core tool is held in apowergrip sothat itdoesn’texitthehandonbeing stroked. Fig 11. Hand grip during making a toolSource:http://www.gavilan.edu.pdf 60 Whenthecoreorotherweaponswereusedforthrowingtostrikeanenemytheywould have needed precision grip. These grips are commonly referred to as thecylinder(power)andball(precision)grips. The remodelling of hand not only included anatomical changes in bone andmusclesofwristandfinger(metacarpals)butalsoneurologicalbasisforvoluntarycontrol developed. These modifications (a) relieved the stresses which wereformed due to opposition of the thumb while manipulating an object and (b)allowed manual dexterity to grip object more firmly or enabled to throw it.Humans also possess flexor pollicislongus muscle which provides strength andcontroltothemovementofthumb(Badeetal.,1993,MarzkeandMarzke,2000). Historyof Human Evolution SUMMARY Evolution of humans has a long history ranging from an earlier genus of apescalled Australopithecus to modern Homosapiens. Middle Pleistocene periodreveals transitional phase of human evolution between the hominins that camebeforeHomoerectusandtheonesthatfollowedmodernHomosapiens.Artifactualtrace of prehistory often provides speculative evidences to paleoanthropologisttounderstandthehomininadaptationtochangingenvironmentandnewbehaviouradopted.Survivalandproliferationofpopulationinthenewenvironmentdemandsnot only anatomical or physiological changes but also cultural and genetictransmission of favourable traits andbehaviour from generation togeneration. REFERENCES Aiello,L.,&Dean,C.(1990).Anintroductiontohumanevolutionaryanatomy.London:AcademicPress. 61 EarlyHominids Bade,H.,Koebke,J.,&Bilger,H.(1993).Functionalanatomyofthefifthcarpometacarpal joint.Handchirurgie, Mikrochirurgie,plastischeChirurgie..,25(3),116-120. Berge, C. (1994). How did the australopithecines walk? A biomechanical studyofthehipandthighofAustralopithecusafarensis. JournalofHumanEvolution, 26(4), 259-273. Bhattacharya,D.K.(1994).AnOutlineofPrehistory.India:PalakaPrakashan. Crabtree,P.J.,Campana,D. V.,&Ryan, K.(Eds.).(1989). Earlyanimaldomestication and its cultural context (Vol. 6). Philadelphia: University ofPennyslvania. D’Août,K.,&Aerts,P.(2008).Theevolutionaryhistoryofthehumanfoot. Advances in plantar pressure measurements in clinical and scientificresearch.Maastricht:ShakerPublishing,44-68. Delson,E.,Tattersall,I.,VanCouvering,J.,&Brooks,A.S.(2004).Encyclopaediaofhumanevolution andprehistory.NY:TaylorandFrancisGroup. Dixson,A.F.,&Dixson,B.J.(2012).VenusfigurinesoftheEuropeanPaleolithic:symbols offertilityor attractiveness?.JournalofAnthropology,2011. EncyclopaediaBritannica.(http://www.britannica.com)asassessedduringSeptember2014. Friedman,M.J.(2006).TheEvolutionofHominidBipedalism.IllinoisWesleyanUniversity.HonorsProjects.Paper16. Retrievedfrom:http://citeseerx.ist.psu.edu/viewdoc/download;jsessionid=53824821E57AC7EBE8ACF6DF82A6609A?doi=10.1.1.684.2832&rep=rep1& type=pdf Gould,S.J.(1977).EversinceDarwin:Reflectioninnaturalhistory.NewYork: W.W.NortonandCompany. Harari,Y.N.(2014).Sapiens:Abriefhistoryofhumankind.India:PenguinRandomHouse. HarcourtSmith,W.E.,&Aiello,L.C.(2004).Fossils, feetandthe evolutionofhumanbipedallocomotion.JournalofAnatomy, 204(5),403-416. Haviland,W.A.,Walrath,D.,Prins,H.E.,&McBride,B.(2011). Evolutionandprehistory:The humanchallenge.Wadsworth:CengageLearning. Holloway,R.L.(1981).Culture,symbols,andhumanbrainevolution:asynthesis.DialecticalAnthropology, 5(4),287-303. Janusch,B.(1969).OriginofMan.WileyEasternUniversity. Jurmain,R.,Kilgore,L.,&Trevathan,W.(2011).EssentialsofPhysicalAnthropology.8thEdition.Wadsworth:CengageLearning. Jurmain,R.,Kilgore,L.&Trevathan.W.(2012).EssentialsofPhysicalAnthropology.9thEdition.Wadsworth: CengageLearning. Jurmain,R.,Kilgore,L.,Trevathan,W.,&Ciochon,R.L.(2014).AnIntroductiontoPhysicalAnthropology2013-2014Edition.Wadsworth:CenageLearning. 62 Lewis,B.,Jurmain,R.&Kilgore,L.(2010).UnderstandingHumans:AnIntroductiontoPhysicalAnthropologyandArchaeology.10thEdition.Wadsworth:CengageLearning. Lovejoy, C. O. (2005). The natural history of human gait and posture: Part 1.Spineandpelvis.Gait&posture, 21(1),95-112. Marzke,M.W.,&Marzke,R.F.(2000).Evolutionofthehumanhand:approachestoacquiring,analysingandinterpretingtheanatomicalevidence.TheJournalofAnatomy,197(1),121-140. Midlo, C. (1934). Form of hand and foot in primates. American Journal ofPhysicalAnthropology, 19(3),337-389. Napier,J.R.(1956).Theprehensilemovementsofthehumanhand.TheJournalofboneandjointsurgery.Britishvolume,38(4),902-913. Richmond, B. G., Begun, D. R., & Strait, D. S. (2001). Origin of humanbipedalism: the knuckle walking hypothesis revisited. American Journal ofPhysicalAnthropology:TheOfficialPublicationoftheAmericanAssociationofPhysicalAnthropologists,116(S33),70-105. Russo, G. A., & Kirk, E. C. (2013).Foramen magnum position in bipedalmammals.Journal of human evolution, 65(5), 656-670. Shefelbine,S.J.,Tardieu,C.,&Carter,D.R.(2002).Developmentofthefemoralbicondylarangleinhominidbipedalism.Bone, 30(5),765-770. Stout, D., Toth, N., Schick, K., &Chaminade, T. (2008). Neural correlates ofEarly Stone Age toolmaking: technology, language and cognition in humanevolution. PhilosophicalTransactionsoftheRoyalSocietyofLondonB:BiologicalSciences, 363(1499),1939-1949. Swindler,D.R.(1996).AnIntroductiontoPrimates.Washington:UniversityofWashingtonPress. Wayman,E.(2012).Becominghuman:Theevolutionofwalkingupright. Smithsonian.com. Wulf, C. (2012). Towards a Historical cultural anthropology of education. InAnthropologiesofEducation:AGlobalGuidetoEthnographicStudiesofLearningandSchooling, (pp. 29-48). NewYork and Oxford: BerghahnBooks. Young, R. W. (2003). Evolution of the human hand: the role of throwing andclubbing.JournalofAnatomy, 202(1),165-174. ANSWERS/HINTSTOCHECKYOURPROGRESS Homoerectus ispopularlyknownas‘UprightMan’. HomoneanderthalensisareconsideredtobethemostcloselyrelatedtothemodernhumanHomosapiens. Duringthecourseofevolutionmany changestookplacewhichwasconsidered significant in defining what makes a hominid. These includebipedlocomotion,largebrainsize,toolmakingbehaviour,developmentof Historyof Human Evolution 63 EarlyHominids languageandculture.Theseevolutionaryprocesseswhichleadtothe developmentofhumancharacteristicsdistinguishedfromprimatesareknownas hominization. Mosaic evolution is defined as the patterns in which physiological andbehaviouralsystemsevolveatdifferentrates.Forfurtherdetailsrefersection4.2.1 Hominid footprints preserved in the ash fall of a volcanic eruption around3.5-3.8millionyearsago(duringPlioceneperiod)atLaetolisiteinnorthernTanzaniarepresentstheearliestevidenceofbipedalisminhumanevolution. Quadraped have vertically elongated hip bones positioned parallel to eachotheralongthesidesofthelowerportionofvertebra.Incontrast,homininsilliumofhipbonebecamecomparativelyshorterandbroader.Remodellingof pelvis lead to basin shaped structure that support abdominal organs andallows transmission of weight from lower back to hip joint during erectposture.For further detailsrefersection4.2.1. Inpowergrip,theobjectmaybeheldinaclampformedbythepartlyflexedfingers and the palm where counter pressure being applied by the thumblying more or less in the plane of the palm while in the precision grip, theobject may be pinched between the flexor aspects of the fingers and theopposingthumb. The neurological modifications that supported in remodelling of hand: (a)Relievingofstresswhichwereformedduetooppositionofthethumbwhilemanipulating an object and (b) Enabling of manual dexterity to grip objectmorefirmlyortothrowit. Forfurtherdetailsrefersection4.2.2. 64