Ukuzaliswa kwezityalo

NguRene Fester Kratz

Izityalo zizinto eziyimpumelelo kakhulu, ezikhula phantse kuyo yonke indawo eMhlabeni. Inxalenye yempumelelo yabo kungenxa yenyani yokuba banokuphinda bavelise ngokwesini nangokwesondo.



  • Xa izityalo zivelisa i-asexually, zisebenzisa mitosis ukuvelisa inzala efana nemfuza kwisityalo somzali. Uncedo lokuveliswa kwakhona kwe-asexual kukuba ivumela izinto eziphilayo ezinempumelelo ukuba zivelise ngokukhawuleza. Ukungancedi kukuba yonke inzala iyafana ngokwemfuza, nto leyo inciphisa ukubanako kwabemi ukusinda kwiinguqu kwindalo esingqongileyo.



  • Xa izityalo zivelisa ngokwesondo, zisebenzisa meiosis ukuvelisa iiseli ze-haploid ezinesiqingatha solwazi lwemfuza lomzali (enye ye-chromosome). Ekugqibeleni, iiseli ze-haploid zivelisa amaqanda kunye nesidoda esidibanisa ukwenza into entsha, eyahlukileyo yemfuza ene-chromosome.

    Uncedo lokuveliswa ngokwesondo kukuba kudala ukwahluka kwinzala, ukwandisa amathuba okuba iintlobo ziya kuphila zijongana notshintsho lokusingqongileyo. Ukungancedi kukuba ezinye izityalo kufuneka zifumane iqabane ukuze zivelise ngokwesondo kwaye zininzi izityalo zifuna amanzi angamanzi ukubakhona ukuze isidoda sikwazi ukudada.



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Imijikelo yobomi bezityalo inzima ngakumbi kunaleyo yezilwanyana. Kwizilwanyana, iiseli ze-haploid zibizwa iijethi (amadlozi kunye namaqanda) zihlala zincinci kwaye zingabonakali. Kwizityalo, nangona kunjalo, iiseli ze-haploid zinokuphila ngokwazo.

Ngaba i-mucinex inyusa uxinzelelo lwegazi

Imijikelo yobomi bezityalo ibandakanya ukutshintshwa kwezizukulwana: Umjikelo opheleleyo ubandakanya izizukulwana ezibini ezahlukeneyo ezibiziweyo sporophytes kwaye iijetophyte . Nalu ukonakala komjikelo:



  1. I-Meiosis kwisityalo somzali, esibizwa ngokuba yi sporophyte, iziphumo kwimveliso ye-spores I-haploid, Kuthetha ukuba banesiqingatha solwazi lwemfuza lwesityalo somzali.

  2. I-spores ziqala ukukhula nge-mitosis, zikhule zibe zii-multicellular haploid eziphilayo ezibizwa iijetophyte.

    Inyathelo le-gametophyte lomjikelo wobomi bezityalo ngumahluko osisiseko phakathi kwezityalo nezilwanyana. Kwizilwanyana, akukho phuhliso lwenzeka de isidoda kunye neqanda zidibane ukuvelisa into entsha. Kwizityalo, kukho ikhefu elincinci phakathi kwe-meiosis kunye nokuveliswa kwesidoda kunye namaqanda. Ngexesha lekhefu, isityalo esincinci esahlukileyo esikhulayo sikhula.

    Isebenza njani lexapro
  3. I-Gametophytes ivelisa iigetetes nge-mitosis.

    Kwizilwanyana, i-meiosis ivelisa isidoda kunye neqanda, kodwa kwizityalo, i-meiosis iyenzeka ukuvelisa i-gametophyte. I-gametophyte sele i-haploid, ke ivelisa isidoda kunye neqanda nge-mitosis.

  4. Iigetet ziyadibana, zivelise iiseli ezibizwa ngokuba iZygotes equlethe inani elifanayo lama-chromosomes njengesityalo somzali-oko kukuthi, i-zygotes yile idiploid.

  5. IiZygotes zahlulahlulwe yi-mitosis kwaye zikhula zibe zi-sporophytes ke umjikelo wobomi ungaqala kwakhona.

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Izityalo ozibona xa uhamba emahlathini zinokuba zi-sporophytes okanye i-gametophytes:

  • Ubulembu obukhula emithini nasemgangathweni wehlathi ziigetthophytes. Ukuba ubona izakhiwo ezincinci ezinjengeeflegi ezibambelele kwi-moss, ujonge isporophyte. Ii-sporophytes ezincinci zikhula njengeeflegi zisuse phezulu kwi-gametophytes. Ngaphakathi kweeflegi ezincinci, ezibiziweyo iifomsile, I-meiosis iyenzeka ukuvelisa ii-spores.

  • Iifeni ozibonayo zii-sporophytes. Ukuba ujonga ngasemva kwamagqabi e-fern, unokufumana izakhiwo ezincinci ezimdaka ezibonakala zinothuli ngaphandle kwebala. Olu lwakhiwo kulapho kwenziwa khona iintsholongwane, kwaye uthuli oluphumayo ziintshulube. I-Fern gametophytes zincinci kakhulu - malunga nokuba zinkulu njengomnwe kwipinkie yakho -zenza kube nzima kakhulu ukuzifumana endle.

  • IiConifers ozibona ehlathini zii-sporophytes. Isizukulwana se-gametophyte kwii-conifers sincinci kakhulu kwaye siqulathwe ngaphakathi kweekhowuni zazo.

  • Izityalo zezimbali ezibonakalayo kwiliso nazo zi-sporophytes. Kwizityalo ezidubula iintyatyambo, isizukulwana se-gametophyte sincinci kakhulu kwaye siqulathwe ngaphakathi kweentyatyambo.