Nyob rau hauv cov kab mob panmictic (kev sib deev yug me nyuam), ib hom kab mob uas zoo sib xws nyob rau hauv tag nrho cov yam ntxwv, muaj peev xwm ntawm kev ywj pheej interbreeding nrog tsim ntawm fertile offspring. Lub tswv yim ntawm kev sib cais yog siv nyob rau hauv cov ntsiab lus ntawm microevolution los yog, raws li nws kuj hu ua, speciation. Kev sib cais ntawm kev yug me nyuam pib txheej txheem ntawm kev tsim ib hom tshiab thiab xaus rau nws. Tab sis tsis yog txhua yam ntawm qhov tshwm sim no yuav ua rau muaj qhov tshwm sim ntawm hom tshiab, ib yam li tsis yog txhua qhov kev sib cais ua rau kev sib cais zaum kawg ntawm cov pejxeem.
Kev cais tawm mechanisms hauv evolution
Inside ib hom, tib neeg muaj nyob rau hauv pab pawg - pejxeem. Nws yog cov pejxeem raws li ib chav tsev ntawm microevolution uas yog cov khoom siv rau kev tsim cov hom tshiab uas txawv ntawm cov qub qub. Nyob rau hauv ib hom, kev sib pauv ntawm cov khoom siv caj ces tshwm sim ntawm cov neeg nyob rau hauv tus txheej txheem ntawm kev yug me nyuam. Qhov hu uakev tsim muaj peev xwm ntawm cov kab mob. Thaum qee qhov kev sib pauv ntawm cov pej xeem nyob rau hauv tib hom yog txwv los yog ua tsis tau kiag li, lawv hais tias kev sib cais ntawm kev sib deev tau teeb tsa. Lub ntsiab txhais ntawm no evolutionary mechanism yog hais tias cov tib neeg ntawm ntau haiv neeg tsis tuaj yeem tsim cov xeeb ntxwv. Keeb kwm ntawm qhov tshwm sim ntawm ib hom tshiab yog cov saw hlau sib txawv ntawm kev sib cais ntawm cov me nyuam sib txawv, hloov los yog sib tshooj, ua rau kev faib ntawm cov pej xeem irreversible.
Kev cais tawm kev sib deev: kev faib tawm
Muaj ntau lub tswv yim hauv kev faib tawm ntau yam ntawm kev cais cov pej xeem. Ntau yam kev coj ua raws li lub ntsiab feature ntxiv ib co tsis meej pem rau qhov teeb meem no. Cia peb coj los ua lub hauv paus uas kev sib cais ntawm kev sib deev raws li kev txwv mus tas li ntawm panmixia (kev hla dawb) yog theem kawg uas ua tiav qhov tshwj xeeb. Cov neeg tawm tsam ntawm qhov kev pom ntawm hom kev sib cais yog cov neeg paub txog kev hloov pauv biologist F. G. Dobzhansky (1900-1975) thiab E. Mayr (1904-2005). Cov txheej txheem ntawm kev sib cais ntawm kev yug me nyuam hauv txoj hauv kev no yuav muab faib ua peb pawg:
- spatial division (geographic);
- kev sib cais ib puag ncig (ib puag ncig mechanisms);
- kev tsim cov txheej txheem tsim nyog, suav nrog kev sib koom ua ntej (ua ntej tsim cov zygote) thiab tom qab kev sib xyaw ua ke (mating tshwm sim, tab sis lub qe tsis fertilized lossis tuag, lossis cov hybrids tsis muaj menyuam) teeb meem.
Txhua yam txheej txheem ua tiav qhov txwvpanmixia: tag nrho los yog ib nrab. Cia peb piav luv luv txog cov qauv ntawm kev sib cais ntawm kev sib deev hauv txhua pab pawg. Cov piv txwv piav qhia lawv yuav pab koj nkag siab qhov tseem ceeb ntawm ib daim ntawv tshwj xeeb.
Spatial mechanisms of pejxeem cais
Lub tshuab ntawm kev sib cais yog cuam tshuam nrog ntau yam kev hloov pauv hauv toj roob hauv pes (qhov pom ntawm qhov thaiv nyob rau hauv daim ntawv ntawm roob toj siab lossis dej ntws) lossis nrog kev sib kis ntawm cov tsiaj nyob rau thaj tsam loj. Thaum qhov kev khiav ntawm cov noob ntawm cov neeg sib cais raug cuam tshuam, kev sib cais ntawm kev sib deev tshwm sim. Cov piv txwv nto moo tshaj plaws ntawm qhov tshwm sim nrog kev tsim ntawm hom tshiab tuaj yeem suav hais tias yog hom kob ntawm bindweeds ntawm Galapagos Islands, uas tau los ua ib qho piv txwv rau Charles Darwin txoj hauj lwm "Lub Keeb Kwm ntawm Hom los ntawm Txoj Kev Xaiv Ntuj". Los yog piv txwv ntawm ib tug xiav magpie, ib tug pejxeem nyob rau hauv Tuam Tshoj thiab lwm yam nyob rau hauv Spain.
Ecological cais mechanisms
Yog vim li cas rau hom kev sib cais no muaj feem cuam tshuam txog qhov sib txawv ntawm cov xwm txheej rau kev yug me nyuam ntawm tib hom tsiaj nyob symmetrically, uas yog, hauv tib thaj chaw. Piv txwv li, lub caij yug me nyuam los yog flowering lub caij tsis coincide. Nyob rau ntawm ntug dej hiav txwv California, ob hom ntoo thuv muaj symmetrically: ib hom tso paj ntoos nyob rau lub Ob Hlis, thiab lwm yam nyob rau lub Plaub Hlis. Kev cais tawm raws caij nyoog ecological tau dhau los ua me nyuam rau lawv. Ib qho piv txwv ntawm kev sib cais ntawm kev yug me nyuam, tab sis tshwm sim los ntawm cov khoom noj sib txawv, yog pom los ntawm peb hom Antarctic cov ntsaws ruaj ruaj tau nqis los ntawm tib yam poj koob yawm txwv phylogenetic. Lub Weddell foob noj ntses nkaus xwb, tsov txaij foob noj penguins thiab cov ntsaws ruaj ruaj, thiab Ross foob nojcephalopods.
Cov ntaub ntawv Precopulatory of reproductive isolation
Kev cais tawm tshuab - qhov tsis muaj txiaj ntsig ntawm kev sib raug zoo los ntawm cov qauv sib txawv ntawm cov menyuam yaus lossis cov kabmob copulatory. Piv txwv li, ntau hom sage muaj cov paj sib txawv thiab pollinated los ntawm lwm cov muv. Tib qhov kev sib raug zoo muaj nyob nruab nrab ntawm orchids thiab hummingbirds. Drosophila yoov interspecies mating ua rau raug mob lossis tuag ntawm tus khub.
Kev cais tawm ntawm Ethological - tsis sib koom ua ke vim qhov sib txawv ntawm kev sib deev (hauv kev sib tham, hu nkauj, seev cev, ci ntsa iab, lossis qhov sib txawv ntawm pheromones). Piv txwv li, zoo sib xws ntawm fireflies, thaum caw ib tug poj niam rau mating, blink txawv (nrog sib txawv zaus thiab ntev). Cov nkauj tshwj xeeb hauv cov noog thiab cov qav kuj tuaj yeem hais hauv cov ntsiab lus no. Thiab txhua leej txhua tus paub txog mating rituals ntawm noog.
Kev cais kev ua si - tsis muaj kev sib cuam tshuam gamete lossis kev tuag ntawm gametes. Lub hav zoov ntawm hom kev rho tawm no tau raug pov thawj sim. Piv txwv li, ob hom hiav txwv urchins nrog rau sab nraud fertilization tau hla los ntawm American geneticists Denis thiab Brachet. Lub qe tau fertilized, tab sis lub embryo tuag nyob rau hauv thaum ntxov theem ntawm gastrulation.
Post-copulation forms of reproductive isolation
Qhov no yog hais txog qhov tsis muaj peev xwm ntawm lub qe fertilized thiab tuag ntawm embryo nyob rau hauv thaum ntxov theem ntawm ontogenesis. Los yog kev tuag ntawm ib tug me nyuam yug los (los yog ib tug neeg) ua ntej mus txog rau kev puberty. Zoo heev tswvyim rau gameticrwb thaiv tsev.
Nyob rau hauv cov tsiaj feem ntau, cov hybrids tseem muaj sia nyob yog tsis muaj menyuam, uas yog, lawv tsis muaj peev xwm tsim tau cov xeeb ntxwv. Ib qho kev zam tuaj yeem yog semi-sterile hybrids. Cov txheej txheem ntawm qhov tshwm sim no yog qhov nyuaj heev, raws li cov noob caj noob ces, chromosomal lossis cytological ua. Peb tsuas yog muab piv txwv ntawm cov hybrids sib txawv uas paub rau txhua tus.
Hybrid nees luav thiab mare - mule. Nws loj dua ib tug nees luav thiab me dua ib tug nees, thiab ntxiv rau, cov tsiaj yog yooj yim khaws cia. Hybrids ntawm cov subspecies zoo sib xws ntawm ib tug dev thiab hma (hma, ib nrab-hma) muaj ib tug ntau tsim instinct thiab endurance tshaj dog dig dog dig. Ntau cov ntses thoob dej yug ntses yog cov ntawv hybrid (cov yeeb yuj aulonocars). Lawv yog cov zoo nkauj, loj dua li niam txiv cov ntaub ntawv, tab sis thaum yuav, koj yuav tsum qhia lub hauv paus chiv keeb ntawm cov ntses, txwv tsis pub koj yuav tsis tos rau cov me nyuam. Txhua leej txhua tus paub tias cov noob ntawm cov nroj tsuag cog (txiv lws suav, dib) cim nrog lub cim F-1 yog cov ntaub ntawv hybrid. Cov txiv hmab txiv ntoo ntawm cov nroj tsuag no tsis tso rau cov noob.
