Cov ntaub ntawv thiab txhua yam kev variability

Nyob rau ntiaj chaw lub ntiaj teb, muaj ntau ntau yam ntau yam ntaub ntawv ntawm lub neej, thiab nyob rau tib lub sij hawm nyob rau nws tsis yog ob tug txawm zoo tib yam tsiaj los yog nroj tsuag. Ntau hom yog sib txawv heev los ntawm txhua lwm yam, tab sis txawm tias cov zoo heev thaum xub thawj siab ib muag, tib hom kab muaj cov tsis muaj ob kiag li zoo tib yam rau txhua tus lwm yam.

Thiab feem ntau kuj ceeb tias, tag nrho cov saum toj no yeej muaj tseeb tsis tsuas yog rau cov creatures uas cov me nyuam kev sib deev, tab sis kuj rau cov neeg uas propagated vegetatively, thiab txawm clones.

Yog li ntawd dab tsi uas muaj sia nyob tus kab mob ntawm lub ntiaj teb tshuav no cov neeg? Qhov tseeb yog tias txij li thaum nws inception - nws tsis, nyob rau hauv daim ntawv ntawm ib tug zygote los yog ib tug me nyuam txoj kev - lub cev pib hloov. Thiab nws tau hloov nws lub neej tag nrho - mus txog rau thaum nws tuag. Qhov no cov khoom teejtug uas tag nrho cov nyob yam hu ua variability.

Txawm li cas los, lub variability yog tsis ib txwm sau rau tib qhov kev pab cuam, tab sis vim hais tias, raws li nws cov kev tshawb fawb, kws tshawb fawb tau pom hom variability.

Yog li, lub variability yuav tsum yog ib tug neeg (ib tug raug muab tau los ntawm), thiab pab pawg neeg (derived ntawm tag nrho cov pab pawg neeg). Tus thawj yog feem ntau.

Tsis tas li ntawd nyob rau hauv ib tug nyias muaj nyias ib hom ntawm geographic variation yog faib, lub txwm uas yog qhov tseeb hais tias cov kev hloov tau yog los ntawm lwm yam tseem ceeb, ib tug tej yam ib ncig.

Sib cais hom variability thiab cov neeg kawm ntawv ntawm hloov dua siab tshiab, yog hais tias nws yog tag nrho, radical, qhov no variability ntawm zoo, thiab yog hais tias tsuas muaj ib nrab hloov dua siab tshiab yog tsis tag, yog ib tug ntau variation.

Yog hais tias ib tug nyob tau cuam tshuam los ntawm tej yam lwm yam provoking tej yam tshwm sim ntawm transformation, nws yog qhia variability thiab yog hais tias tus hloov dua siab tshiab tshwm sim nthawv, nws yog uas tsis yog-directional volatility. Nyob rau hauv tas li ntawd, muaj ib tug kev loj hlob variability yog ib qho tu ncua thoob plaws txoj kev loj hlob thiab kev ua neej hloov kab mob.

Txawm tias muaj tseeb hais tias muaj ntau yam thiaj li xaiv rau ib tug tau hloov dua siab tshiab yam ntxwv rau tej yam tshwm sim ntawm yeeb tshuaj, tsis yog txhua txhua yam zoo mas yuav kis tau los ntawm nws kis tau mus rau nws cov xeeb ntxwv. Yog li ntawd, txawm cais li nram qab no variation: raws roj ntsha thiab nonhereditary (kev hloov kho).

Txawm li cas los, qhov no tsis xaus muaj. Nws yog raws roj ntsha thiab uas tsis yog-raws roj ntsha yam ntaub ntawv ntawm variability muab faib mus rau hauv subtypes. Cov subtypes txawv rau ib tug ntau yam ntawm cov yam ntxwv thiab cov khoom. Thiab lawv yog hu ua, kom yooj yim, cov ntaub ntawv.

Yog li ntawd, yog cov nram qab no ntaub ntawv ntawm variability: Kev hloov kho thiab genotypic. Kev hloov kho, kuj hu ua phenotypic, manifested los ntawm qhov tseeb hais tias txawv cov neeg ntawm lub tib lub hom nyob rau hauv tus ntawm ib puag ncig yog hloov phenotype. Cov uas ua tus kab mob no yog ib tug neeg hloov yuav tsis pub.

Piv txwv li, yog tias ib tug dandelion paus yog phua rau hauv ib nrab thiab muab tso rau hauv sib txawv tej yam kev mob (ib tug ib nrab - nyob rau hauv lub roob, lub thib ob - nyob rau hauv lub hav), los ntawm lub sij hawm lawv mus txog tiav nkauj tiav nraug nroj tsuag yuav tsum tau kuj cuab kev uas cov nroj tsuag phenotype yog radically sib txawv. Loj hlob nyob rau hauv lub roob ntawm dandelion yog stunted, cov nplooj thiab paj yog tsis loj. Tab sis cov nroj tsuag tau raug zus nyob rau hauv lub hav, rau lwm cov tes, yuav siab thiab nws cov nplooj - loj. Yog hais tias lub xeeb leej xeeb ntxwv ntawm cov nroj tsuag loj hlob nyob rau hauv tib tej yam kev mob, qhov sib txawv therebetween yuav tsis tau.

Lub ntsiab tseem ceeb ntawm no kev hloov kho yog qhov adaptability ntawm lub sia rau qhov tam sim no ib puag ncig.

Genotypic variability yog fundamentally sib txawv ntawm cov kev hloov kho, raws li ib tug tshwm sim ntawm nws tsis hloov lub phenotype thiab genotype, thiab cov tshiab mas yuav kis tau attribute yog pub. Genotypic variability yog muab faib ua ob subspecies: combinative thiab hloov (hloov).

Combinative variability - yog lub rov tshwm sim ntawm tshiab khoom nyob rau hauv cov xeeb ntxwv vim tej yam tshiab ob peb ua ke ntawm cov noob los ntawm nws niam nws txiv. Piv txwv li, nyob rau hauv lub hla ntawm qab zib taum mog nrog dawb paj nyob rau hauv lawv cov xeeb leej xeeb ntxwv paj tej zaum yuav liab doog xim.

Hloov - ib tug cia li, tab sis nyob rau tib lub sij hawm ib tug neeg twg kev hloov ntawm cov kev tshuaj ntsuam genetic khoom siv ntawm ib tug kab mob, kis tau mus rau xeeb leej xeeb ntxwv. Change nyob rau hauv ib tug neeg thiab tsom.