Ntuj xaiv yog yeej ib txwm lub ntsiab zoo tshaj nyob rau hauv lub transformation uas muaj sia nyob. Nws ua los ntawm cov tib mechanism - ciaj sia thiab khaws cov lusteb zag, piv txwv li, fittest. Txawm li cas los, nyob ntawm seb nws cov hauj lwm zoo, cov kev taw qhia, tshwj xeeb tshaj yog cov tej yam kev mob ntawm cov hav zoov ntawm cov kab mob no - rau hauv daim ntawv ntawm tej yam ntuj tso xaiv tej zaum yuav txawv. Yog li, ib tug ntawm nws cov ntaub ntawv yog cov dynamic xaiv (directional), uas yog ib lub teb rau cov kev hloov nyob rau hauv ib puag ncig thiab muaj txhawb rau ib tug ua haujlwm ntawm qhov phem feature los yog tej khoom vaj tse. Rau ntau cov yam ntxwv nruab nrab tus nqi yog lub xam mean nqi, piv txwv li - qhov nruab nrab ntawm ua offspring. Ib tug piav qhia rau cov zoo cov khoom txiav txim zaus (feem pua) ntawm nrws nrog ib tug tsim nyog feature, piv txwv li - qhov zaus thiab hornless horned nyuj.
Analysis ntawm cov zog muab ib tug hais txog ntawm cov kev hloov uas muaj emerged nyob rau hauv cov pejxeem vim lub adaptation rau hloov ib puag ncig tej yam kev mob. Nyob rau hauv no dynamic xaiv yuav ua rau kom ob leeg dag zog rau thiab tsis muaj zog cov kev hloov thaj chaw ntawm tus kab mob. Ib qho piv txwv ntawm lub nce cov yam ntxwv tej zaum yuav yog li ntawd-hu ua industrial melanism. Saib npauj npaim peppered npauj nyob rau hauv uas tsis yog-muaj tej qhov chaw muaj teeb dawb lias teev uas npog lub cev thiab tis, thiab nyob rau hauv cheeb tsam uas muaj ib tug loj tus naj npawb ntawm factories ntawm lawv cev nqaij daim tawv puv dub. Lub rov tshwm sim ntawm npaub txawv txawv rau lawv kom muaj xim vim lub fact tias cov teeb meem muaj emissions tau coj mus rau kev tuag ntawm Lichens uas nyob rau hauv bark ntawm cov ntoo thiab butterflies pab raws li ib tug qhov chaw ntawm kev sib hais haum (tiv thaiv coloration). Xim Hloov teev txhim kho tau txoj kev ciaj sia taus ntawm butterflies. Nyob rau hauv cov ntaub ntawv no, nws txhais li no-hu ua xaiv - cov preservation thiab nce qib ntawm ib tug tshiab hom ntawm butterflies tias nyob rau hauv lub hloov yam no tau mus ntxiv cov haiv neeg, uas yog, muab yug.
Ib qho piv txwv ntawm lub attenuation cov yam ntxwv yog cov poob los yog yuav txo tau ntawm lub cev thiab nws qhov chaw nyob rau hauv Vim lub fact tias nws tsis dais tej load - cov tis ntawm ib tug qaib ntxhw (tsis ya), tsis tuaj kawm ntawv ntawm nqua nyob rau hauv nab.
Dynamic xaiv yog raws li nyob rau hauv dag. Yog li ib tug neeg xaiv cov neeg raws li tej yam tsis (phenotype), tsub kom lub zaus ntawm cov cuab yeej no. Empirically qhov tseeb hais tias qhov kev xaiv los ntawm lawv cov tsos ua rau ib co kev hloov nyob rau hauv genotype, thiab tej zaum tsis tau muaj ib co alleles. Muaj ib co ntaub ntawv ntawm cov khoom cua xaiv - nco thiab methodical. Thaum uas siv cov ib tug xaiv ntawm cov tsis nco qab tus txiv neej, raws li nws intuitively xaiv qhov zoo tshaj plaws. Cov tshwm sim ntawm xws li ib tug qauv yog qhov tshwm sim ntawm tshiab breeds thiab ntau yam yam ntxwv rau ib tug tas. Methodological ntsiab cai siv nyob rau hauv kev xaiv los tsim tshiab hom ntawm cov nroj tsuag thiab cov tsiaj nruj heev heev rau tej kev loj hlob tej yam kev mob thiab kev pab (txias-resistant hom ratseny).
Yog li, lub dynamic xaiv - yog ib daim ntawv ntawm tej yam ntuj tso xaiv, qhov tshwm sim ntawm uas yog cov tsos ntawm ib tug tshiab txais hom kab mob uas muaj peev xwm ciaj sia thiab mus txuas ntxiv lawv tsev neeg nyob rau hauv lub hloov ib puag ncig.