Menene zabin yanayi? Nau'in zabin yanayi (tebur)

Daya daga cikin manyan hanyoyin tsarin juyin halitta a Bugu da kari maye gurbi, hijirarsa da kuma gene canji ne zabin yanayi. Nau'in zabin yanayi yakan haifar da irin canje-canje a cikin genotype, wanda kara jiki ta chances na rayuwa da kuma procreation. Juyin Halitta ne sau da yawa gani a matsayin wani sakamako na da wannan tsari, wanda zai iya haifar da daga bambance-bambance a cikin nau'in rayuwa rates, haihuwa rates, da taki na raya kasa, nasarar da ma'abota ko wani al'amari na rayuwa.

balance yanayi

gene mitoci haƙuri daga tsara zuwa tsara, da sharadin cewa akwai wani damuwa abubuwan da rushe da na halitta balance. Wadannan sun hada da maye gurbi Hijira (ko gene kwarara), bazuwar kwayoyin gantali da zabin. Maye gurbi - wani yunkri canji na gene mitoci a wata alƙarya, wanda aka halin a low kudi na ci gaba. A wannan yanayin, mutum motsa daga daya yawan zuwa wani, sa'an nan kuma modified. Random kayyade gantali - wani canji cewa yana daukar kwayar cutar daga tsara zuwa tsara gaba daya bazuwar.

Dukkan wadannan dalilai canza mita da kuma ware genes kara ko rage yiwuwar rayuwa kwayoyin da kuma wasa da baya a cikin halitta yanayi. Dukan su ne bazuwar tafiyar matakai. A zabin yanayi, iri zabin yanayi ne matsakaici ansu kafofin tarwatsa sakamakon wadannan matakai, tun da sun ninka da mita daga m maye gurbi domin da yawa da kuma kawar da cutarwa aka gyara.

Menene zabin yanayi?

Zabin yanayi na taimaka wa adana wadanda kungiyoyin na kwayoyin da aka fi saba da jiki da kuma nazarin halittu yanayin da mazauninsu. shi
za su iya aiki a kan wani heritable phenotypic dabiu da kuma yin amfani da zabe matsa lamba iya shafar duk wani al'amari na yanayi, gami da jima'i selection da gasar tare da membobin wannan ko wasu nau'in.

Duk da haka, wannan ba ya nufin cewa wannan tsari ne ko da yaushe directed da kuma m, a Na'urar juyin halitta. Zabin yanayi, iri zabin yanayi a matsayin dukan, sau da yawa kai ga kawar da kasa fit bambance-bambancen karatu.

Bambance-bambance wanzu a cikin dukan jama'a na kwayoyin. Wannan shi ne jera domin akwai bazuwar maye gurbi a cikin genome na guda kwayoyin, da kuma 'ya'yan ta iya gada irin maye gurbi. Kan rayuwa da kwayoyin hulɗa tare da yanayi. Sakamakon haka, yawan faro.

A ra'ayi na zabin yanayi

Zabin yanayi ne daya daga cikin na kan kusurwar zamani ilmin halitta. Yana abubuwa a kan phenotype, kwayoyin akai wanda ya ba mai haihuwa amfani ga mafi girma ruwan dare a cikin yawan. A tsawon lokaci, wannan tsari zai iya kai zuwa fitowan da sabon nau'in. A wasu kalmomin, wannan shi ne wani muhimmin (ko da yake ba kawai) wani tsarin juyin halitta a cikin wata alƙarya.
The sosai ra'ayi da aka tsara da kuma buga a 1858 by Charles Darwin da Alfred Russel Wallace a cikin hadin gwiwa biyayya da takardun game da Origin of Species.

A lokaci da aka bayyana a matsayin kwatanci ne ga wucin gadi selection, watau aiwatar da abin da dabbobi da kuma shuke-shuke da wasu halaye dauke kyawawa don jan iri da haifuwa. Kalmar "zabin yanayi" asali ci gaba a cikin rashi na gado ka'idar. A lokacin rubuta ayyukansa Darwin kimiyya da duk da haka ya ci gaba da ka'idar zamani itatuwa aure. Hada gargajiya Darwin juyin halitta da m binciken a na gargajiya da kuma kwayoyin halittar jini da ake kira zamani juyin kira. 3-daban na zabin yanayi ya zauna da primary bayani ga Na'urar juyin halitta.

Ta yaya zabin yanayi?

Zabin yanayi - wani inji ta da dabba jiki adapts da kuma ta faro ne. A da ginshikin, mutum kwayoyin da aka fi dace da yanayi da kuma tsira haifa mafi nasarar, an samar da m zuriyarsa. Bayan da yawa hawan keke na haifuwa irin jinsin su ne marinjãya. Kamar wancan yanayin tace talauci saba mutane domin amfanin aukacin jama'ar.

Wannan shi ne mai gwada da sauki inji cewa yana sa 'yan wani musamman yawan canji na tsawon lokaci. A gaskiya, shi za a iya karya cikin biyar na asali matakai: canzawa, gado, selection, lokaci da kuma karbuwa.

Darwin na zabin yanayi

Bisa ga koyarwar Darwin zabin yanayin kunshi hudu aka gyara:

1. Bambance-bambance. Kwayoyin a cikin wata alƙarya nuna mutum bambance-bambance a bayyanar da hali. Wadannan canje-canje na iya hadawa da jiki size, gashi launi, spots a kan fuskarsa, da kaddarorin na murya ko da yawan zuriya samar. A daya hannun, wasu halaye ba a hade tare da bambance-bambance tsakanin mutane, kamar yawan idanu a vertabrate.
2. Jẽre. Wasu fasaloli na cikin jerin sun shige daga iyaye zuwa zuriya. Irin wannan halaye ne gaji, yayin da wasu da aka karfi da ya rinjayi muhalli yanayi, kuma suna gaji rauni.
3. A high girma kudi na yawan jama'a. The girma na dabbobi don samar da zuriya kowace shekara a yawa ya fi girma yawa fiye da yake bukata domin daidaita rarraba albarkatun tsakanin su. Wannan take kaiwa zuwa interspecific gasar, da kuma wanda bai kai ba mace-mace.
4. A bambanci rayuwa da kuma haifuwa. Kowane irin zabin yanayi a alƙarya bar baya da waɗanda dabbobi da suke iya gasa for gida albarkatun.

Natural Selection:-daban na zabin yanayi

Darwin ta ka'idar juyin halitta halin canza shugabanci na nan gaba na kimiyya da tunani. A cikin hedkwatarsu da wani zabin yanayi tsari, wanda ya auku a kan m zamaninsu, kuma aka bayyana a matsayin bambanci haifuwa genotypes. Duk wani canji a cikin yanayi (msl, canji launi daga wata itãciya akwati) zai iya haifar da gida karbuwa. Wadannan iri zabin yanayi (ga tebur lamba 1):

tabbatar da dorewar selection

Sau da yawa mita na maye gurbi a cikin DNA a wasu jinsunan ne na ilimin kididdiga fi a cikin sauran. Wannan irin zabin yanayi na taimaka wa da kawar da duk wani ta'addi a phenotypes mafi saba da yanayi na mutane da a cikin yawan. Wannan rage bambancin cikin guda jinsunan. Duk da haka, wannan ba ya nufin cewa dukan mutanen da ya samu cikakken m.

A tabbatar da dorewar zabin yanayi da kuma iri za a iya taƙaice bayyana a matsayin averaging ko karfafawa, a cikin abin da yawan ne mafi kama. Da farko ya rinjayi fallasa polygenic halaye. Wannan yana nufin cewa phenotype ne sarrafawa da dama kwayoyin halitta, kuma akwai wata fadi da kewayon yiwu sakamakon. A tsawon lokaci, wasu daga cikin kwayoyin halittu suna kashe ko masked da sauran, dangane da kunna karbuwa.

Mutane da yawa mutum halaye ne sakamakon wannan selection. The nauyi na wani mutum a haifi - shi ne ba kawai a polygenic hali, shi ne kuma sarrafawa da muhalli dalilai. Jariri da wani talakawan nauyi a haihuwa ne mafi kusantar su tsira fiye da da ma kananan ko ma manyan.

Directed halitta daga zabin yanayi

Wannan sabon abu ne yawanci lura a cikin yanayi, wanda ya canja a kan lokaci, misali, weather, sauyin yanayi, ko da adadin abinci zai iya kai wa ga directional selection. mutum hannu iya bugun sama da tsari. Dayansu sau da yawa kashe fiye da dabbobi don samar da nama, ko kuma wasu manyan ado ko amfani sassa. Sakamakon haka, yawan zai ayan skew zuwa ga karami mutane.

A ya fi girma dabbobi masu cin nama kashe da kuma ci m kifi a cikin yawan jama'a, haka nan muradinka zai kasance ouschestvlyatsya Ƙirgar zuwa ga mafi nasara da kuma fi sauri wakilan da yawan jama'a. Nau'in zabin yanayi (tebur tare da misalai № 1) na iya zama mafi vividly nuna yin amfani da misalai daga yanayi.

Charles Darwin karatu da directional selection, sa'ad da yake a cikin Galapagos Islands. A tsawon baki na gida kananan tsuntsaye canza a kan lokaci saboda data kasance ikon kafofin. Idan babu tsira kwari kananan tsuntsaye da manyan beaks da kuma dogon, wanda ya taimaka musu don ci da tsaba. Tun da shi ya zama mafi kuma yin amfani da tsuntsu beaks directional selection hankali samu karami kwari a kan lokaci.

Features diversification (subversive) selection

Damuwa selection - wani irin zabin yanayi, wanda aka yi tsayayya da su averaging jinsin halaye a cikin yawan. Wannan tsari ne ya fi rare, idan muka bayyana da iri zabin yanayi a taƙaice. Divesifikatsionnaya selection iya kai wa ga kebantaccen biyu ko fiye daban-daban siffofin a cikin wurare na kaifi canje-canje a cikin yanayi. Kamar yadda directional selection, wannan tsari na iya ma za a ragae saboda da hallakaswa da tasiri na mutum factor da kuma gurbacewar muhalli.

Daya daga cikin mafi kyau-karatu misalai na ansu kafofin tarwatsa selection shi ne yanayin da malam a London. A yankunan karkara, kusan dukan mutane suna da haske da launi. Duk da haka, wadannan guda malam kasance sosai duhu a cikin masana'antu yankunan. Akwai kuma lokuttan da wani talakawan launi tsanani. Wannan shi ne saboda gaskiyar cewa duhu malam koya wa tsira da kubuta daga yara a cikin masana'antu a cikin yankunan birane halin wurare. Light kwari a masana'antu yankunan ana iya gano da kuma ci da yara. A daura da hoton da aka lura a yankunan karkara. Malam talakawan launi tsanani ne sauƙi a bayyane a duka wadannan wurare, don haka suna da sosai kadan.

Saboda haka, ma'anar subversive motsi phenotype selection ne zuwa matsananci, wanda wajibi ne ga rayuwa cikin jinsin.

Zabin yanayi da kuma ci gaba

Ainihin ra'ayin da ka'idar juyin halitta ne cewa duk nau'in bambanci hankali samo asali daga sauki rayuwa siffofin da suke da fiye da uku biliyan shekaru da suka wuce (don kwatanta, da shekaru na Duniya ne game da 4.5 biliyan years old). Nau'in zabin yanayi tare da misalai daga farko kwayoyin da farko zamani mutane taka leda a cikin juyin ci gaban muhimmiyar rawa.

Kwayoyin da cewa an talauci saba da su yanayi ne m iya tsira da kuma haihuwa. Wannan yana nufin cewa su kwayoyin halittu ne m iya yaduwa zuwa ƙarni na gaba. A hanya zuwa ga bambancin kwayoyin kamata ba za a rasa, kazalika da da ikon a salon salula matakin amsa canza muhalli da yanayi.