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thE Evolution oF sEx rAtios hAs proDuCED, in most plAnts AnD AnimAls with sEpArAtE sExEs, ApproximAtEly EquAl numBErs oF mAlEs AnD FEmAlEs. why shoulD this BE so two mAin kinDs oF AnswErs hAvE BEEn oFFErED、onE is CouChED in tErms oF ADvAntAgE to populA tion. it is ArguED thAt thE sEx rAtio will EvolvE so As to mAximizE thE numBEr oF mEEtings BE twEEn inDiviDuAls oF thE oppositE sEx. this is EssEntiAlly A "group sElECtion" Argu- mEnt. thE othEr, AnD in my viEw CorrECt, typE oF AnswEr wAs First put ForwArD By FishEr in 1930. this "gEnEtiC" ArgumEnt stArts From thE Assumption thAt gEnEs CAn inFluEnCE thE rElAtivE numBErs oF mAlE AnD FEmAlE oFFspring proDuCED By An inDiviDuAl CArrying thE gEnEs. thAt sEx rAtio will BE FAvorED whiCh mAximizEs thE numBEr oF DEsCEnDAnts An inDi viDuAl will hAvE AnD hEnCE thE numBEr oF gEnE CopiEs trAnsmittED、supposE thAt thE populA tion ConsistED mostly oF FEmAlEs, thEn An inDiviDuAl who proDuCED sons only woulD hAvE morE grAnDChilDrEn. in ContrAst, iF thE populAtion ConsistED mostly oF mAlEs, it woulD pAy to hAvE DAughtErs. iF, howEvEr, thE populAtion ConsistED oF EquAl numBErs oF mAlEs AnD FEmAlEs, sons AnD DAughtErs woulD BE EquAlly vAluABlE. thus A onE-to-onE sEx rAtio is thE only stABlE rAtio; it is An "EvolutionArily stABlE strAtEgy. "Although FishEr wrotE BEForE thE mAthEmAtiCAl thEory oF gAmEs hAD BEEn DEvElopED, his thEory inCorporAtEs thE EssEn tiAl FEAturE oF A gAmE thAt thE BEst strAtEgy to ADopt DEpEnDs on whAt othErs ArE Doing.
sinCE FishEr’s timE, it hAs BEEn rEAlizED thAt gEnEs CAn somEtimEs inFluEnCE thE Chro mosomE or gAmEtE in whiCh thEy FinD thEmsElvEs so thAt thE gAmEtE will BE morE likEly to pArtiCipAtE in FErtilizAtion. iF suCh A gEnE oCCurs on A sEx-DEtErmining (x or y) Chromo somE, thEn highly ABErrAnt sEx rAtios CAn oCCur.But morE immEDiAtEly rElEvAnt to gAmE thEory ArE thE sEx rAtios in CErtAin pArAsitiC wAsp spECiEs thAt hAvE A lArgE ExCEss oF FE mAlEs. in thEsE spECiEs, FErtilizED Eggs DEvElop into FEmAlEs AnD unFErtilizED Eggs into mAlEs.A、FEmAlE storEs spErm AnD CAn DEtErminE thE sEx oF EACh Egg shE lAys By FErtilizing it or lEAving it unFErtilizED、By FishEr’s ArgumEnt, it shoulD still pAy A FEmAlE to proDuCE EquAl numBErs oF sons AnD DAughtErs. hAmilton, noting thAt thE Eggs DEvElop within thEir host--thE lArvA oF AnothEr insECt--AnD thAt thE nEwly EmErgED ADult wAsps mAtE immEDi AtEly AnD DispErsE, oFFErED A rEmArkABly CogEnt AnAlysis. sinCE only onE FEmAlE usuAlly Eggs in A givEn lArvA, it woulD pAy hEr to proDuCE onE mAlE only, BECAusE this onE CoulD FErtilizE All his sistErs on EmErgEnCE. likE FishEr, hAmilton lookED For An EvolutionArily stABlE strAtEgy, But hE wEnt A stEp FurthEr in rECognizing thAt hE wAs looking For A strAtE gy.
thE Author suggEsts thAt thE work oF FishEr AnD hAmilton wAs similAr in thAt Both sCiEntists______.A．ConDuCtED thEir rEsEArCh At ApproximAtEly thE sAmE timE
B．sought to mAnipulAtE thE sEx rAtios oF somE oF thE AnimAls thEy stuDiED
C．sought An ExplAnAtion oF why CErtAin sEx rAtios Exist AnD rEmAin stABlE
D．stuDiED rEproDuCtion in thE sAmE AnimAl spECiEs