Yintoni na le nto ukuzala (Biology, iBakala 8)

Yintoni na le nto ukuzala, yaye ziziphi izinto zayo? Lo mbuzo kukade icangcisiwe umdla izazinzulu ezininzi, ukusukela lokwanda eziphilayo zohlobo lwazo yinto yokuqala efunekayo ukuze ubomi on Earth.

Yintoni buphindwe

Undoqo yale nkqubo bubonakala lokwanda ngohlobo lwazo. Kwaye umbuzo apha akukho malunga umbala amehlo okanye isakhiwo iinwele. Kubalulekile ukuba umzimba, owabakhoyo kuphela yabakho kwindawo yokuhlala ethile, nako ukusinda kuso. Ingaba kuphela iimpawu ezithile noshowo lweentlobo, njengelifa izinyanya. Kungenjalo bonke yoqhekeko, sandivusa njengomntu-zamasele ukusuka movie efanayo.

eziphilayo Indlela zokuzalela

Ingaba kukho ezahlukene phakathi ukuzala maqanda kunye ngokwesini? Ngokuqinisekileyo. Kwimeko yokuqala, hayi inxaxheba gametes, kule yesibini phambi kwabo kuyimfuneko. Kukho iindlela ezininzi yokuzalana maqanda. Elula kubo - lo ukwahlulwa ibe ezimbini iiseli. Ngoko ke ezizalana iibhaktheriya, izilwanyana abangatshatanga-ezineseli kwakunye nezityalo. Kuba Plasmodium falciparum esibonakala kwisahlulo isininzi apho omnye iiseli umzali nangoko kwasekwa ezimbalwa abaxhasi elinesibini. Ngenxa nokukwazi iiseli ukuba zahlule, balungise ancedisana amalungu, kunye nezilwanyana ezininzi bayakwazi ngokutsha ngokukhawuleza. Umzekelo, amanzi hydra, nto leyo emele i- uhlobo Coelenterates, ungakwazi ukudlula ukusuka kwiindawo 1/200.

Le ephilayo phinda yi lolu. Kulo mzekelo, umzimba kuqala kwi Buze olukhula, ithatha phezu iimpawu kumzimba koomama, uze emva koko Wazityanda off kwaye iqala khona elizimeleyo.

Bonke bakonwabela ukutya nge nagwele. Ngoko ke, ukwanda kwenani labo - akukho nto kodwa inkqubo yavelisa amagqabi fungi.

Izityalo ayakwazi yokuzala kwezityalo. Le ndlela ukwahlula kuyo yonke ingxenye multicellular ephilayo. Xa ntyatyambo le njongo, amagqabi, itapile - modified amahlumelo komhlaba (amatswele), Iidiliya - izithole.

Yintoni na le nto ukuzala

Le nkqubo lwenzeka kuphela inxaxheba gametes - iiseli ezizodwa lokuzala: Amadoda - somyeni, nabafazi - amaqanda. Bona ziqulathe ulwazi lwabo nuclei yemfuza eziqulathwe iimolekyuli DNA.

Undoqo wenkqubo ukuzala ke recombination yale nto. Yaye usoloko awudingi gametes. Ngoko ke, izihlangu ciliates uza conjugation. Ngoko ke umzimba ezimbini lisondela kunye naphakathi kwabo ezikhandelwa ibhulorho cytoplasmic, apho ukutshintshiselana ngumongo imixholo yazo.

Izinto eziluncedo ze ukuzala

Ngenxa recombination ingqubana - amacandelo iimolekyuli DNA - umzimba ukwazi bafumane imisebenzi emitsha kunye luncedo. Eyona ukubaluleka ukuzala kulo. Emva kokuba ngokucandeka iiseli koomama wambumba ikopi yayo ngqo. Enye efakiwe nje ndawo ukuthatha. Xa iimeko zokusingqongileyo utshintshe, eziphilayo ezinjalo abakwazi ukuziqhelanisa, nto leyo eya ekugqibeleni kukhokelela ekonakaleni kwabo ukuncitshiswa iyantlukwano iintlobo ngokubanzi.

iimpawu ezitsha kwakheka kuphela utshintsho mbandela yemfuza. Ngoko ke yimfuzo balinqabisa kwinani ngezizukulwana.

yokuveliswa kwezityalo nezilwanyana

Yintoni na le nto ukuzala izityalo, uyakwazi ukuqwalasela imizekelo omfisi, nto leyo ke izityalo iphezulu ibihlungu. Kwicala esezantsi amagqabi aluhlaza abaqolileyo isakhiwo ezikhethekileyo - sori. Bona zinokuphikiswa - iiseli yokuzala maqanda. Ukufumana kumhlaba olumanzi, ngoko ke ihlume, kusekwe isityalo oluncinane. Kungenisa amaqanda kunye amadlozi, leyo bahlanganisane ngababini, zizale lokutyala entsha eluhlaza. Nantso i alternation isizukulwana ngokwesondo - le gametophyte kunye maqanda - sporophyte.

Xa kweentyatyambo izityalo, andisa okuvelisa sisetyenziselwa intyatyambo. In evuthiwe ababhinqileyo gamete pistil, istameni kunye anther - abantu. Ngenxa neqanda kwakhiwa umbungu imbewu. Kuba elizayo, uphuhliso kunye nokukhuselwa ngayo inani elikhulu kwezinto reserve, iziqhamo agcwele okanye bulishica iqokobhe.

Izilwanyana kwakhona iiseli ezikhethekileyo kunye namaziko apho afumaneka - ndlala. Abameli kule ubukumkani kukho iintlobo ezininzi isichumiso. Xa fusion engaphandle gametes kwenzeka ngaphandle komzimba nemazi, njengoko iintlanzi okanye izilwanyana eziphila emhlabeni nasemanzini, xa izala amaqanda emanzini kwakunye nokugalelwa ayo amadlozi eyindoda. Kutheni amaqanda abantu abaninzi kangaka? Oku yindlela zebhayoloji ukugcina inani labantu abadala ngenxa yokuba iiseli ungakhuselekanga, yaye inkoliso yabo badle ezizingelayo. Kwimeko lwangaphakathi neqanda umzimba elizayo ixesha elithile emzimbeni sikanina. Ngoko ke, inani kwamaqanda ekwaziyo isichumiso, ngakuba nomtsalane kangaka.

Lowo ngumongo ukuzala, apho kukho iintlobo ezintsha zezityalo neentlobo zezilwanyana, kwakunye ngenxa ukuba kube lula ukwenza gqith kunye eziphilayo eyenziwe.