Uzinzo ukhetho: uhlobo nokubaluleka kwayo ebomini bomntu

Njengoko sisazi ukuba eziphilayo, umzekelo, kukho izityalo relict, njengoko ginkgo, okanye nokuba loo iintlanzi Crossopterygii njenge coelacanth kukho, phantse akukho lutshintsho malunga neminyaka kwesigidi. Njani oku kuchazwe yi uzinzo iintlobo nje njalo iinkqubo yemfuza kwindalo? Impendulo yalo mbuzo unikwa Kwakungokuba ingcamango "yenze ukhetho" - imfundiso esele yenzelwe yi izinto zazivelela ezidume II Schmalhausen.

uhlobo wathi ukhetho ibonakala kuphela kwiimeko rhoqo yokusingqongileyo ixesha ngokwaneleyo elide. Kungenxa yoko le nto imvelo efanayo, ngokubanzi, mava kunye ngokuphelele ukuba ngamnye yakhe ngandlel kula eziguqulwe kufuneka kutshabalala. Ukukhetha kungako ingqinwa inani elaneleyo imizekelo. Ngoko ke, emva kokuba imimoya nekhephu malunga 136 ndiqhiphuke oongqatyana isiqingatha-abafileyo kwafunyanwa North America, baye basinda abantu 72 kuphela. Phakathi kwabo kwakukho oongqatyana ukuba umyinge amaphiko, ngenxa ekuye kwafuneka ukunyamezela ngaphezu kwabo baye baba amaphiko ende kakhulu okanye emfutshane kakhulu.

inkqubo yokukhetha uzinzo kukhokelela kwi ukufana phenotypic yabemi. Kunye negalelo lakhe ixesha elide kwi-bume unokunika umbono ukungaguquleki kweentlobo okanye izilwanyana. Nangona kunjalo, oku kuphela ukungaguquleki kuyacaca kwaye Ukuze ndizixhalabise imbonakalo kuphela. Xa le pool gene ivavanywa utshintsho ethile (wezakhi kwenzeka).

Gulwa uphawu Ukukhethwa yendoda. Umzekelo Phantsi engqondweni. Yinto eyaziwayo ukuba izifo zofuzo ezifana kunokubangela ukuphazamiseka kwi ngababini ezincinane 21-22 zofuzo. Kwimeko Nakuphi na ukutenxa kule mali kunye nefomu zofuzo ezinkulu, kukho nokutshatyalaliswa amaqanda ivundiswe. Kwakhona izisu avele badla sisizekabani sokufa kwelungisa ngeembumba abanala makhwiniba chromosomal phakathi.

Gulwa yokukhetha amakhulu amawaka izizukulwana; linoxanduva ulondolozo kweentlobo utshintsho olukhulu ngokuthi lisuswe ifomu promutirovavschie. Ngaphandle kwalo, kwakungayi ekufikelelwe uzinzo ethile kwindalo.

Kunye nokuzinzisa sele kuxoxwe, kukho ukhetho ngamnye, nto leyo uluncedo ukuqwalasela umzekelo kwezityalo. umongo walo kukuqinisekisa umgangatho kwizityalo ekhethiweyo ngoncedo uvavanyo ngamnye progenies zabo. Mu kuya kwa nshita ukhetho ngobuninzi, musa mix kwi iimbewu ngamnye yezityalo ezikhethiweyo kwaye kuhlwayelwa ngokwahlukeneyo iintsapho kwiindawo ezithile ukuze ufumane ingqikelelo olungileyo wembewu yabo. Nale ndlela, ungafumana ukhetho kwi kweejini kunokuba phenotype.

Ukukhetha zingqondweni sifaneleke ngakumbi emntwini, babathwalela ngaphandle umsebenzi advance ethile. Ngenxa yoko, Darwin wabonisa ukuba, umzekelo, phambi kuqoqosho yamahlwempu iimazi ezimbini, kuba inyama yona eyixhelela lowo onika ubisi ngaphantsi, kunye neenkuku ukuba inyama nezikhukukazi imbi iya kusetyenziswa kuzo. Kwaye enye yaye kwimeko yesibini, umfama ukuze kugcinwe izilwanyana nemveliso, ukwenza ukhetho, musa sizibekele usukelo zokuphuhlisa iintlobo ezintsha. Kungenxa kule fomu ngandlel isintu Darwin yaye ibonisa ukhetho zingqondweni.

Ngokufundisisa ubomi bezizwe ka-Australia kunye noMzantsi Afrika, iingcali zenzululwazi kusiba niyohlwaywa ukuchaneka izigwebo zabo. Ukukhetha zingqondweni ixesha elide ukuze umntu xa balawule izilwanyana zasendle. Ukuba oku kuqulunqo kwisigqibo ebalulekileyo kwezolimo iintlobo ezintsha zezilwanyana nezityalo zingafunyanwa kuphela ngokusebenzisa kweesampula. Ngoko ke, imfundiso kukhetho zingqondweni zayo Darwin "hlobo" omnye, akukho ngaphantsi ebalulekileyo, imfundiso ukhetho ngumntu, nto leyo kwenziwa ngohlobo lo mthetho, ukuba ndizinyathele yonke inkqubo yokuphuhlisa iintlobo zezityalo ezintsha iintlobo zezilwanyana.