Sihloko: "Kungani izitshalo zom kokukhulelwa ngokuthi kabili" ukutadisha lesithupha. Nokho, akubona bonke abantu abadala ungakwazi ukuchaza butholakala enqubweni eyinkimbinkimbi yokuthela inqubo.
Izitshalo, njengazo zonke izinto eziphilayo zizalana, usebenzisa izindlela ezintathu eziyinhloko. Esokuqala vegetatively, okungukuthi, kwesitshalo esisha siphuma iyiphi ingxenye "umzali" yayo - impande, isiqu, amaqabunga, ngisho kuseli eyodwa. Eyesibili libizwa asexual, ngoba izitshalo ziyaphuma impikiswano futhi zifana umzali. Ngakho wande isikhunta futhi abanye ulwelwe. I eziphambili kakhulu iyona ukuzalanisa izitshalo indlela ngokobulili.
Esikhathini umbuso isitshalo, le nqubo kwenzeka Fusion gametes ukuthi kungaba ezifanayo ngobukhulu (isogamy), ezinobukhulu ezahlukene (heterogamy) futhi ngokuyisisekelo ukuhluka nezinye (oogamy) ngamunye. Singasho ukuthi kokukhulelwa - inqubo uxhumano besilisa (isidoda) nensikazi (amaqanda) gametes, kuphumele kwamangqamuzana nokwakheka kwamanye ingaphazamiseki neqoqo double wama-chromosomes (i-zygote), kanye okuyoba isitshalo entsha.
Kungani kokukhulelwa e nezitshalo eziqhakazayo ngokuthi double? Lapha kukhona ekhethekile Izitho zokuzala - imbali. Izingxenye zalo ingxenye ku sesigcilikisha stamen nge anther (impova equkethe), esibelethweni, ikholomu, pistil (inhlamba c), impova ishubhu, okuyinto eza ku-embryo sac lapho ovule. Yiqiniso esikoleni yezinto eziphilayo, abantu abaningi bekhumbula okuthile mayelana pistil futhi stamen futhi bangase bacabange yingakho ukuzalanisa nezitshalo eziqhakazayo ngokuthi kabili. Kodwa lokhu akulona icala.
Ngo anther, njengoba sekushiwo, kwakheka ke impova, esakhiwa amaseli ezimbili - vegetative ezinkulu nezincane ngobukhulu, okuzala. Lapho anther wakwambula, lezi zinto chithi umoya noma izinambuzane. Uma phezu pistil (inhlamba ngqo kwi) impova amaseli ziqhume ukuze vegetative ingxenye iba impova ishubhu enamathiselwe sac umbungu. Through cell yakhe okuzala engena esikhwameni, okuyinto ngokuhamba Ukungena yayo ihlukaniswe ezimbili isidoda. Omunye wabo ifinyelela iqanda, okuhlanganisiwe nalo ukwakha zygote, kanti eyesibili ehlangene nucleus yesibili. Le nqubo isizathu sokuthi kungani ibizwa ngokuthi kokukhulelwa kabili eziqhakazayo.
Ezinye izitshalo yesimanje ngempumelelo ukuhlanganisa izindlela ezahlukene imifanekiso, okwandisa izinga Ukuqhubeka kwalezi zilwane zikhona. Futhi ngesikhathi lapho le nqubo osanda kuzalelwa, le ndlela yokuzala kubaluleke kakhulu, inqubo yokuziphendukela kwemvelo. Lokhu kungenxa yokuthi umzimba adalwe cell Fusion ne amasethi ezahlukene wama-chromosomes possessed kokuhlukana enkulu kanye nezimo emvelweni. Modern izifundo physico-chemical aye alubonisa kanjani ukuzala of the complex isitshalo ngokwemvelo. Ngokwesibonelo, kuye kwatholakala ukuthi impova nenhlamba ningabaleli pH ezahlukene, amazinga ehlukene amaprotheni amaphuzu isoelectric, ezahlukene enzyme nama-amino acid ukwakheka Nokho, okuyinto, ikhuthaza izinqubo elilungile bokuphila avuze lapho yokuxhuma kulezi cells.