NgoMeyi 15, 1953, usokhemisti owayeneminyaka engama-23 ubudala wapapasha kwiphephancwadi i<em>Science iziphumo zolingelo olubalulekileyo kwibhayoloji olwavula indlela yenkalo entsha yolwazi lwenzululwazi. Lo mfana yayinguStanley L. Miller. Umsebenzi wakhe waba nguvulindlela kuqeqesho lwekhemistri ye-prebiotic njengoko siyayazi namhlanje kwaye wasinika imikhondo yokuqala malunga nokuba ubomi bavela njani eMhlabeni. I Miller ulingelo Yaziwa kakhulu kwihlabathi lezenzululwazi.
Ke ngoko, siza kunikezela eli nqaku ukukuxelela yonke into ekufuneka uyazi malunga novavanyo lukaMiller kunye nokuba lubandakanya ntoni na.
Umhlaba wokuqala
UStanley Miller wayesandula ukuphumelela kwichemistry kwaye watshintshelwa kwiDyunivesithi yaseChicago enombono wethisisi yobugqirha. Kwisithuba nje seenyanga ezimbalwa esebenza, owawongwa ngembasa yeNobel uHarol C. Urey waphumelela ekholejini waza uMiller waya kwisemina yakhe ngemvelaphi yomhlaba kunye neatmosfera yamandulo. Intetho yatsala uMiller kakhulu kangangokuba wagqiba ekubeni atshintshe umxholo wethisisi kwaye wanika uYuri ngovavanyo angazange azame ngaphambili.
Ngalo mzuzu, Isazi ngemichiza yezinto eziphilayo saseRashiya uAlexander I Opalin wapapasha incwadi enomxholo othi “The Origin of Life”. Kuyo, wachaza indlela iinkqubo zemichiza ezizenzekelayo ezikhokelela ekuveleni kweendlela zobomi bokuqala, eziye zaphuhliswa ngokuthe ngcembe kwixesha lezigidi zeminyaka.
Malunga neebhiliyoni ezi-4 zeminyaka eyadlulayo, iimolekyuli ze-inorganic zomhlaba wakudala ziya kusabela ukuvelisa iimolekyuli zokuqala zendalo, ukusuka apha iimolekyuli ezintsonkothileyo, kwaye ekugqibeleni izinto zokuqala.
U-Oparin wayenombono womhlaba wamandulo owahluke ngokupheleleyo kumhlaba wangoku, ngaphambi kokuba utshintshwe sisidalwa ngokwaso.
Imikhondo evela kuvavanyo lukaMiller
Enye yezinto ezibonisa ukuba wawunjani lo Mhlaba wamandulo isekelwe kulwazi olukhoyo lwenzululwazi ngeenkwenkwezi. Ukucinga ukuba umhlaba kunye nezinye iiplanethi kwi-solar system zivela kwilifu elifanayo legesi kunye nothuli, ukubunjwa kwe-atmosphere yomhlaba kunokufana kakhulu neeplanethi ezifana neJupiter kunye neSaturn: ngoko, kusenokwenzeka ukuba ityebile kwimethane, ihydrogen, neammonia. Oku kuya kuba yi-atmospheric yokunciphisa kunye nogxininiso lwe-oksijini ephantsi kakhulu kuba eli ligalelo kade lebhaktheriya yokuqala ye-photosynthetic.
Umphezulu womhlaba uya kuntywiliselwa emanzini. Ulwandle lutyebile kwiimolekyuli zemichiza. UOparin wayenombono wolwandle lwamandulo njengesuphu yamandulo etyebile kwiimolekyuli zemichiza.
Eli hlabathi lamandulo liya kuba nesiphithiphithi ngakumbi kunehlabathi lanamhlanje, kunye nentshukumo yentaba-mlilo rhoqo, izaqhwithi zombane rhoqo, kunye nemitha yelanga eyomeleleyo (ayikho i-ozone yokuphepha imitha ye-ultraviolet). Ezi nkqubo Ziya kunika amandla okusebenza kweekhemikhali okwenzeka elwandle kwaye ekugqibeleni ziya kukhokelela ekuveleni kobomi.
Izazinzulu ezininzi, kuquka uYuri, ziye zabelana ngezi ngcamango. Kodwa leyo yayiyintelekelelo emsulwa, akukho mntu uyizamileyo, ingasaphathwa eyokuba ivavanyiwe. Kwade kwavela uMiller.
Uvavanyo lukaMiller nzulu
UMiller wayenombono wovavanyo oluza kuvavanya uluvo lukaYuri no-Opalin kwaye lucenge uYuri ukuba aluphumeze. Uvavanyo olucetywayo lubandakanya ukuxubana kweegesi ekukholeleka ukuba zikho kwi-atmosfera yoMhlaba yokuqala-i-methane, i-ammonia, i-hydrogen, kunye nomphunga wamanzi- kunye nokuvavanya ukuba ziyakwazi na ukusabelana omnye komnye ukuvelisa iikhompawundi eziphilayo. Kufuneka uqinisekise ukuba inkqubo iqhutywa phantsi kweemeko ze-anaerobic (oko kukuthi, ngaphandle kweoksijini) kwaye ayibandakanyi izinto eziphilayo ezinokukhuthaza ukusabela.
Ngenxa yesi sizathu, wayila isixhobo seglasi esivaliweyo esineflaski kunye netyhubhu, ioksijini ayinakungena, kwaye wayicoca zonke izinto ezisetyenziswayo ukuphelisa zonke iintlobo zobomi. Wagalela intwana yamanzi emele ulwandlekazi oluphambili kwiflaski. Wazalisa enye iflaski ngemethane, ihydrogen, neammonia njengomoya wokuqala.
Apha ngezantsi, i-capacitor ivumela izinto ezenza kwi-atmosfera ukuba zipholile kwaye zixube ngokukhutshwa okuveliswe ngama-electrode amabini, okuya kulinganisa iziphumo zombane.
UMiller waqhuba uvavanyo ngobunye ubusuku. Xa ndibuyela elebhu ngentsasa elandelayo, amanzi eflaskini aye ajike ayetyheli. Emva kweveki yotyando, yahlalutya amanzi amdaka kwaye yafumanisa ukuba iikhompawundi ezininzi zaveliswa ezazingekho ngaphambili, kubandakanywa i-amino acids ezine (iikhompawundi ezisetyenziswa zizo zonke izinto eziphilayo njengezinto zokwakha iiseli) (iprotheni).
Uvavanyo lukaMiller lubonisa ukuba ukuba iimeko zokusingqongileyo zichanekile, iimolekyuli ze-organic zinokuthi zenze ngokuzenzekelayo ukusuka kwiimolekyuli ezilula.
Iimolekyuli ze-Organic ezivela emajukujukwini
Nangona kunjalo, kwiminyaka embalwa kamva, izazinzulu zagqiba ekubeni iqondo lokunciphisa kwi-atmosfera yangaphambili lalingaphantsi kunelo uYuri noMiller babecinga, kwaye linokuquka i-carbon dioxide kunye ne-nitrogen. Imifuniselo emitsha ibonisa ukuba, phantsi kwezi meko, ukuhlanganiswa kwezinto eziphilayo azinamsebenzi. Kunzima ukucinga ukuba isobho esihle kangaka sinokunika ubomi. Kodwa ke isisombululo sale ngxaki savela, kungekhona kwiimvavanyo ezintsha eMhlabeni, kodwa ... ukusuka kwindawo.
Ngowe-1969, i<em>meteorite eyilwe kwiminyaka eyi-4.600 yeebhiliyoni eyadlulayo yawela kufutshane neMurchison, eOstreliya. Emva kokuhlalutya, kwafunyaniswa ukuba iqulethe iindidi zeemolekyuli eziphilayo, kuquka i-amino acids kunye nezinye iikhompawundi ezenziwe nguMiller kwibhubhoratri.
Ngale ndlela, ukuba iimeko zomhlaba wamandulo azifanelekanga ukwenza iimolekyuli zezinto eziphilayo, Izinto zasemzini kusenokwenzeka ukuba zisebenzise imichiza eyaneleyo ukuze zinonge isuphu efumaneka emhlabeni kwaye masibone ubomi okokuqala.
Okwangoku, iingcali zibonakala ziphinde zithambekele kwimeko yokunciphisa yasekuqaleni kwaye zityekele ngakumbi kwiziphumo zikaMiller. Ngoko ke, yamkelekile into yokuba, ukuba umoya wesijikelezi-langa sethu uyacutheka, kusenokwenzeka ukuba kusenziwa iikhompawundi eziyimfuneko kubomi basemhlabeni, yaye ukuba umoya ojikeleze umhlaba wethu uyarusa, zisenokuba negalelo kwii<em>meteorite neenuclei ze<em>comet.
Nangona kunjalo, nokuba yaqala kwisijikelezi-langa sethu okanye ngaphandle kwesijikelezi-langa sethu, uvavanyo oluninzi olwahlukeneyo luye lwabonisa ukuba iikhompawundi ze-organic zinokuba ngumphumo wokusebenza kwemichiza ngokulula.
Ndiyathemba ukuba ngolu lwazi unokufunda ngakumbi malunga novavanyo lukaMiller.