Pas az paydoishi fotosintez va mubodilai aerobii moddahoi nakhustin hodisai muhimi evolyutsiyai biologi – paydoishi eukariot va organizmhoi serhujayra ba shumor meravand.
Dar natijai hamzistii mufid – simbiozi hujayrahoi prokariotii gunogun, organizmhoi hastador yo eukarioti paydo shudand (rasmi 2.9). Zaminai asosi baroi simbioz, ehtimol, hujayrahoi amyobashakli geterotrofi budand.
Gizoi onho hujayrahoi mayda bud. YAke az obekthoi gizoii chunin hujayraho metavonist bakteriyahoi aerobii oksigenro nafasgiranda boshad. Onho qobiliyat doshtand, ki dar dokhili hujayrai sohib faoliyat namuda, energiya hosil kunand. On hujayrahoi amyobashakli kalone, ki dar jismi onho bakteriyahoi aerobi oseb namedidand, nisbat ba hujayrahoe, ki energiyaro bo rohi anaerobi megiriftand, dar sharoiti musoidtar qaror doshtand. Badtar bakteriyahoi simbiozi ba mitokhondriya tabdil yoftaand.
Sipas, ba jildi hujayrai sohib guruhi duyumi simbiontho – bak-teriyahoi qamchinakdori ba spirokhethoi hozira monand chasTarzi paydoishi simbiozii eukariotho pida qamchinak va mijgonak paydo shud. Dar natija, qobilyati in guna organizmho baroi harakat va daryofti gizo afzud. Hamin tavr, hujayrai oddii hayvon – peshguzashta-goni soddatarinhoi qamchinakdori hozira paydo shudand.
Eukariothoi harakatkunanda bo rohi simbioz ba vujud omada, organizmhoi qobili fotosintez (mumkin sianobakte-riyaho) – obsabzho yo rastanihoro dodaand. Muhimash on ast, ki sokhti majmui pigmenthoi bakteriyahoi anaerobii qobili fotosintez doshta, ba pigmenthoi rastanihoi sabz benihoyat monand meboshad. Tasodufi nest, ki chunin monandi daleli dar ravandi evolyutsiya tabdil yoftani dastgohi fotosintezkunandai bakteriyahoi anaerobi ba dastgohi shabeh ba rastanihoi sabz boshad.
Farziyahoi bo rohi simbiozhoi payiham paydo gashtani hujayrahoi eukarioti asos doshta, onhoro bisyor olimon etirof mekunand. YAkum, obsabzhoi yakhujayra holo ham ba mavjudot (jonvaron)-i – eukarioti aloqa dorand.
Masalan, dar jismi infuzoriyai patakcha obsabzi khlorella zindagi mekunad. Duyum, baze organellahoi hujayra, masalan, mitakhondriya va plastidho, az jihati KDN-i khud ba hujayrahoi prokarioti – bakteriyaho va sianobakteriyaho monand meboshand.
Imkoniyati istifodai omilhoi muhiti beruna dar eukariotho beshtar ast. Sabab dar on ast, ki dastai khromosomahoi organizmhoi hastador diploidi buda, har kadomi on dar du variant vomekhurand.
Barobari paydo shudani dastai diploidii genho mubodilai genhoi organizmhoi gunoguni mansubi yak namud rukh dod va in ba paydoishi afzoishi jinsi ovarda rasond. Dar hududi erahoi Arkhey va Proterazoy binobar paydo shudani afzoishi jinsi organizmhoi zindai gunogun paydo shudand, zero kombinatsiyai (mubodilai) genhoi gunogun ba amal omad. Organizmhoi yakhujayra dar Zamin bosurat afzudand, vale imkoniyati onho baroi ishgol kardani muhiti zist mahdud bud.
Onho beandoza niz kalon shuda nametavonistand. Sabab dar on bud, ki organizmhoi yakhujayra tavassuti sathi badan nafas megirand. Dar natijai buzurgshavii andozai organizmi yakhujayra, sathi boloi badani on bo tanosubi murabba (kvadrati) hajmi on boshad, bo mukaab (kub) ziyod meshavad. Az hamin sabab, parda (membrana)-i biologie, ki hujayraro ihota mekunad, qobiliyati bo oksigen tamin kardani organizmi on qadar kalonro nadorad. Rohi digari evolyutsiya boshad, badtar ba vujud omad, yane hamon vaqte ki organizmhoi serhujayra paydo shudand (2.6 mlrd. sol pesh az in). Imkoniyati evolyutsiyai organizmhoi serhujayra vasetar ast.
Bori nakhust baroi fahmidani rohhoi paydoishi mavjudoti serhujayra olimi nemis E.Gekkel kushish kardaast (1874). Gekkel ba tadqiqothoi A.O.Kovalevskiy va olimoni digar dar borai inkishofi chanini lansetnik takya namuda, oidi paydoishi mavjudoti serhujayra farziya peshnihod kard. U qonuni biogenetikiro ba asos girifta, takhmin mekard, ki har yak davrai ontogenez takrori hamon davrahoe meboshad, ki guzashtagoni hamon namud dar davrai filogenez az sar guzaronida budand. Muvofiqi tasavvuroti Gekkel davrai zigota ba peshguzashtahoi mavjudoti yakhujayra, davrai blastula ba tuda (koloniya)-i kurashakli qamchinakdorho muvofiq ast. Az rui farziyai mazkur dar oyanda yak tarafi tudai kurashakl furu rafta (monand ba gastrulyatsiya dar lanset nik), organizmi farziyavii dutabaqa paydo shudaast, ki onro Gekkel gastrey nomid, zero on ba gastrula monand bud.
Tasavvuroti Gekkel dar masalai paydoishi organizmhoi serhujayra dar ilm bo nomi nazariyai gastrey mashhur ast. Ba mulohizahoi mekhanikii Gekkel, yane monand kardani davrai ontogenez bo davrahoi evolyutsiyai olami organiki, nigoh nakarda, nazariyai gastrey dar tarikhi ilm naqshi muhim bozid, zero aqidai monofilii (az yak resha) paydoishi mavjudoti serhujayraro ustuvor sokht.
Asosi tasavvuroti hozira dar borai paydoishi organizmhoi serhujayra farziyai I.I.Mechnikov (1886) – farziyai fagositella meboshad. Az rui takhminhoi u organizmhoi serhujayra az soddatarinhoi tudagi – qamchinakdorho paydo shudaand.
Misoli on az qamchinakdorone, ki holo vujud dorand, volvoks meboshad (rasmi 2.10.).
Volvoks hujayrahoi gunogun dorad, chunonchi hujayrahoi harakatkunanda, qamchinakdor, hujayrahoi gizogiri, (hujayrahoe, ki tumaro doshta ba daruni tuda mebarand), hujayrahoi jinsi (vazifai onho az afzoish kardan iborat ast).
Tarzi avvalini gizogirii chunin organizmhoi sodda fagositoz bud. Hujayraho tumaro doshta, dar dokhili tuda omekhta meshudand. Bad az in, dar hujayraho bofta – endo-derma hosil meshud, ki vazifai hozimaro ijro mekard.
Hujayrahoi dar berunmonda vazifai his kardani tasirot, muhofizat va harakatro ba jo meovardand. Az onho boftai pushish – ektoderma paydo shud.
YAk qismi hujayraho baroi ijroi vazifai afzoish makh- sus gashta, ba hujayrahoi jinsi tabdil yoftand. Bo hamin roh, tuda ba organizmi serhujayrai oddi, vale mukammal, tabdil meyobad. Sodda budani sokhti organizmi serhujayra – trikhoplaks tasdiqi farziyai fagositella meboshad.
Olimi rus A.I.Ivanov muayyan kard, ki trikhoplaks az jihati sokht ba mavjudoti farziyavii fagositella monand buda, boyad hamchun tipi makhsusi olami hayvonot – fagositelashaklon judo karda shavad. On fazoi kholiro dar bayni organizmho serhujayraho va yakhujayragiho pur mekunad.
Talabot ba afzudani surati harakat, ki baroi doshtani tuma zarur bud, ba tafriqshavii minbada takon bakhshid.
In dar navbati khud evolyutsiyai organizmhoi serhujayra (hayvonot va rastaniho)-ro tamin karda, sershaklii hayot afzud.
Dar rasmi 2.11 marhilahoi asosii evolyutsiyai khimiyavi va biologi nishon doda shudaand.
Hamin tavr, paydoishi hayot dar rui Zamin ba ravandhoi evolyutsiyai duru darozi khimiyavi aloqamand ast. Tashkil yoftani sokhti uzvhoe, ki organizmro az muhiti beruna judo mekunad, membranai hujayra ast. Membrana khosiyathoi makhsus doshta, takoni muhim baroi paydoishi organizmhoi zinda ast va on ibtidoi evolyutsiyai biologi meboshad. CHi tavre ki organizmhoi zindai sodda 3 mlrd. sol qabl paydo va tadrijan murakkab shudaand, hujayra niz chunin zinai tashakkulro az sar guzaronidaast.
Savolho baroi sanjish:
- Mohiyati farziyai paydoishi eukariotho bo rohi simbiogenez az chi iborat ast?
- Hujayrahoi eukariotii nakhustin energiyai baroi ravandhoi hayot zaruriro bo kadom roh megiriftand?
- Dar kadom organizmho bori nakhust dar ravandi evolyutsiya afzoishi jinsi paydo shudaast?
- Mohiyati farziyai I.I.Mechnikovro oidi paydoishi orga-nizmhoi serhujayra fahmoned.
Istilohot:
- Protobiontho – organizmhoi toyadrogie, ki pardai yadro va qobiliyati khudhosilshavi nadorand.
- Katalizatorho – molekulahoi safeda, ki dar mahluli obi bo fishori atmosfera tabadduloti biokhimiyaviro metezonand.
- Kodi genetiki – sistemai «navishtani» akhbori irsi dar molekulai KDN dar shakli paydarhamii nukleotidho.
- Hudhosilshavi – ravandhoe, ki dar natijai on organizm kombinatsiyai navi genhoro hosil mekunad.
- Prokariotho – mavjudoti tohujayragi, ki qobiliyati mubodilai modda, khudhosilshavi va gayrahoro dorand.
- Fotosintez – ravandi dar rastanihoi sabz bo tasiri nuri oftob hosil shudani moddahoi organiki az gayriorganiki.
- Eukariotho – organizmhoe, ki hujayraashon yadroi mutashakkil doshta, az sitoplazma bo parda judo ast.