Idan muka duba kewaye da mu, zamu gane, ba tare da kokari sosai ba cewa komai yana canzawa koyaushe, babu wani abu a cikin yanayi ko al'adu wanda yake tsayayye, akwai canje-canje da ke faruwa a hankali fiye da wasu, amma komai, kwata-kwata komai, yana canzawa koyaushe. Juyin halitta.
Na wannan gaskiyar nau'in halittu ba sa kubuta, wanda a gare mu, don fahimtarmu, saboda wannan shine yadda muka gansu, wannan shine yadda muka sansu kuma muna iya kasancewa daidai yayin rayuwarmu, amma waɗanda suka sadaukar da kansu don nazarin su da mahimmanci da hanyoyin kimiyya. , ku sani cewa kowane daya daga cikin halittu masu rai da muka sani kuma suke tare da mu, sakamakon wasu sauye sauye ne kuma zai ci gaba da kasancewa haka, matukar dai akwai rayuwa a duniya. Saboda rayuwa taci gaba ne da cigaban halittu.
Yanzu, tun farkon zamanin dan adam akwai maganganu game da dumbin halittu masu rai da ake dasu a doron kasa kuma ana iya tambaya wadanne hanyoyin ne ke da alhakin bambancin sifofi da ayyukan da jinsin halittu daban-daban suke bi? Ko yaya mutane suka dace da wannan babban matakin rayuwar?
Bari mu ɗan kalli tarihi
Yawancin ra'ayoyin farko game da asalin rayuwa suna da alaƙa da sihiri ko addini. Wasu sunyi imanin cewa an halicci kwayoyin ne daga kwayoyin halitta marasa karfi. Irin waɗannan ra'ayoyin da ba su dace ba sun samo asali ne tun zamanin masana falsafa na Girka Anaximander da Aristotle. Ga mutane da yawa ya zama kamar bayyane, alal misali cewa ƙwayoyin ƙudajen sun samu kwatsam daga rubabben nama. A cikin 1861 masanin ilmin kimiyar kemist da na kwayoyin cuta Tabbas Louis Pasteur ya inganta ka'idar tsara kwatsam.
A cikin karnonin da suka gabata, addini yana da tasiri mai tasiri kan hangen nesa na al'ummomi: masu imani suna ɗaukar ƙirƙirar ƙwayoyi a matsayin aikin Allahnsu ko alloli. Al’ummar Yahudu da Nasara, alal misali, sun yarda da gaskiyar hakikanin halitta, kamar yadda yake a rubuce a cikin asalin Tsohon Alkawari. Wannan imanin da aka sani da halitta, ya tabbatar cewa Allah ya halicci nau'ikan halittu masu rai, a yadda suke a yanzu, kuma wannan ba zai iya canzawa ba. Har zuwa tsakiyar karni na XNUMX, yawancin masana kimiyya sun yarda da wannan tsarin, kuma a yau Krista da yawa har yanzu suna jingina ga ainihin gaskiyar labarin asalin. Koyaya, ra'ayi na kimiyya ya canza dangane da wasu sabbin abubuwan lura masana halitta da ƙasa sun yi shi a cikin ƙarni na XNUMX da XNUMX.
A shekara ta 1730s ɗan asalin Sweden mai suna Carolus Linnaeus (Carlvon Linné) a cikin Spanish Linnaeus, ya aiwatar da aikinsa na kirkirar gano alaƙar dake tsakanin jinsuna daban-daban ta hanyar tsara su da tsari.
(Taxonomy) wannan ya haifar da kyakkyawan duban kamanceceniyar dake tsakanin wasu nau'in. Nazarin nazarin halittu ya fara bayyana yadda halittu daban-daban a kallon farko zasu iya raba wasu halaye na tsari, yana haifar da jita-jita game da wani nau'in nasaba ko asalin asali a tsakanin su.
Tsarin ƙasa
Masana ilimin kasa sun gano cewa duwatsun na dauke da yadudduka daban-daban (strata), wadanda aka kirkira a lokuta daban-daban. Waɗannan rukunin duwatsu sun daɗe tun kafin kowace ranar da coci ta sanya don halittar duniya.
Wasu strata dauke burbushin dabbobi da tsirrai wanda ya rayu a lokacin da dutsen ke samuwa: da yawa daga cikin wadannan kasusuwa na halittu ne wadanda ba a san su a duniyar yau ba. A cikin burbushin halittu daban-daban, za a iya kamanceceniya da tsarin dake wakiltar kwayoyin halittar da suka rayu a lokutan baya. Tsoffin duwatsun da suke kan, mafi sauƙin rayuwa da sifofin rayuwa.
Duk wannan ya nuna cewa kwayoyin halittar yau sun samo asali ne daga sifofin farko na rayuwa, wadanda suka samu aiwatarwar sauyi a hankali, ma'ana, juyin halitta.
Ka'idojin juyin halitta
Da farko ba abu ne mai sauki ba ga duniya ta yarda da shaidar juyin halitta, duk da cewa ana iya tabuka komai. Dogon lokaci, coci, ba tare da jayayya ko hujja tabbatacciya da za ta musanta ba, gaskiyar rubutun, kuma ta ba da shawarar cewa Allah ya sanya burbushin a cikin duwatsu yayin halitta don ya gwada imanin muminai.
erasmus darwinLikitan Burtaniya, masanin falsafa kuma mawaki, shine marubucin ɗayan farkon ka'idojin juyin halitta. erasmus darwin ya gabatar da cewa rayuwa ta bunkasa ne daga tushe guda daya, kuma ya bayyana mahimmancin gwagwarmayar rayuwa da zabar jima'i a matsayin wata hanya ta canjin canjin halitta. Yawancin ra'ayoyinsa sun rinjayi jikansa, masanin ƙasa Charles Darwin, wanda ka'idar juyin halitta tasa tayi tasiri mai dadewa akan ilmin halitta. Koyaya, marubucin farkon ka'idar juyin halitta shine masanin halittun Faransa Jean- Baptiste de Lamark.
Jean Baptiste de Lamark
Jean-Baptiste Pierre Antoine de Monet, Knight na Lamarck, mutum ne mai mutunci amma mai rikici. An yaba masa da sanya sunan kimiyya ga "Biology" kuma shine mashahurin marubucin binciken akan furen Faransa. Ya kuma rubuta kundin rubutu mai juzu'i bakwai a kan "invertebrates," kalmar da ya gabatar don bayyana dabbobi ba tare da kashin baya ba. Sha'awarsa ta kai ga sauran fannoni, gami da ilimin ƙasa da nazarin burbushin halittu, kuma kodayake da farko ya yi imanin cewa nau'ikan halittu sun kasance ba su canzawa ba a cikin 1790s sai ya koma imani da juyin halitta.
Lamarck, ya gamsu cewa kwayoyin sunada rikitarwa. Ya kuma kammala da cewa dadaddun halittun da ake zaton basu mutu ba sun bace, amma kawai sun canza zuwa wasu sifofin zamani kuma juyin halittar halittu abu ne da ke tafiya a hankali. Lamarck ya ba da gudummawa ga imanin cewa tsarin jiki yana ƙarfafa kuma yana haɓaka saboda yawan amfani da shi, da kuma cewa ƙananan sassan da aka yi amfani da su sun raunana ko raguwa: zato na amfani da rashin amfani A cikin irin wannan hanyar na yarda cewa waɗannan haruffan da aka samo a lokacin rayuwar kwayoyin za a iya watsa su ga zuriyarsu.
Shahararren hoto na wannan gaskiyar shine dokin wuƙumin rakumin dawa. Dangane da tunanin amfani ko rashin amfani, kokarin da raƙuman raƙuman ruwa suka yi zuwa ganyen manyan rassa zai haifar da miƙa wuya da zuriyarsu za su gaji wannan halin da suka samu don haka suna da ɗan wuyan wucin gadi. Don haka a tsawon lokaci da ƙarni da yawa yawancin raƙuman raƙuman wuyan wucin wucin gadi zasu kasance.
Lamarck ya wallafa ka'idarsa ta juyin halitta a cikin Falsafar Zoological kuma ana kushe shi sosai. Sunansa ya kasance yana da alaƙa ta wata hanyar da ba ta dace ba ga rainin hankalin rabon gado na haruffan da aka samo, wanda ake kira lamarquism.
Har Charles Darwin ya samar da irin wannan tsarin na gado, wanda ya kira shi pangenesis. Sake sake ganowa, a cikin 1900, na Gwajin gwajin jini na Mendel zai sa a sami ingantaccen hoto na gado.
A halin yanzu sananne ne cewa halayen da suka gada daga iyayensu ta hanyar zuriya an same su a lokacin haɗuwa, ma'ana, ana watsa su, a cikin tsarin kwayoyin halitta, ta DNA na maniyyi da ƙwai na halittar mahaifa da uwa kuma wannan ba matsala ba ce ta hanyar rayuwar da ta gaba ta waɗannan kwayoyin. Kodayake ana iya canza DNA ta wasu nau'ikan maye gurbi da wasu dalilai na muhalli, kamar su ionizing radiation, ba za a iya canza shi ta hanyar yanayin kwayoyin halitta ba.
Darwiniyanci
A cikin 1858, masanin Biritaniya, Alfred Russel Wallace ya aika wa Darwin da rubutu mai taken dabi'ar nau'ikan karkacewa daga na ainihi, gwargwadon karatun da ya yi game da dabbobin tsibirin Malay, na Indonesia a yau. Wannan masanin kimiyyar ya lura da cewa wadannan jinsunan Asiya. Sun kasance masu ci gaba ta fuskar juyin halitta fiye da Australiya kuma ya ba da shawarar cewa sun samu ya samo asali ne bayan nahiyoyin biyu sun rabu.
Darwin ya yi mamakin ganin cewa an karanta Wallace ga al'ummar Linnaean ta Landan, amma babu Darwin ko Wallace da suka halarci taron kuma taron bai tayar da sha'awa ba.
A watan Nuwamba 1859 Darwin ya wallafa asalin jinsin ta hanyar zabin yanayi ko kuma kiyaye jinsin da aka fi so a cikin gwagwarmayar rayuwa. A cikin wannan littafin Darwin ya fahimci cewa Wallace ya kusan yanke hukunci iri daya kamar yadda nayi game da asalin halittu.
An takaita ka'idar Darwiniyanci game da zabin yanayi a cikin wadannan maki:
- Za'a iya samun bambance-bambancen da ke cikin sifa tsakanin mutane na kowane jinsi, girma, launi, tsakanin wasu, na yawancin halayensa.
- Jinsunan da ke haifar da jima'i suna da 'ya'ya da yawa fiye da yadda ake buƙata don kiyaye yawan mutane a cikin jama'a.
- A matsakaici, kowane mutum yana da ɗan siririn damar tsira zuwa balaga.
- Wannan yiwuwar rayuwa zai iya zama mafi girma idan mutum yana da wasu halaye na girma, siffa, launi, tsakanin sa’o’i waɗanda zasu sa ya fi dacewa da yanayinsa. Bayan haka an ce yana da fifikon zaɓi a kan takwarorinsa.
- Mutanen da suka fi dacewa don rayuwa a cikin yanayin su har zuwa lokacin da suka balaga zai iya samun damar haihuwa da kuma watsa kyawawan halaye ga offspringa theiran su.
- Akasin haka, waɗancan mutane waɗanda halayensu ya sa ba za su iya rayuwa zuwa balaga ba suna da 'ya'ya kaɗan kuma ba za su iya yada halayensu ba.
- Bayan ƙarni da yawa yawan zuriya da halaye masu kyau za su ƙaru kuma lamba da lamba tare da halaye marasa ƙarancin halaye za su ragu.
Littafin Darwin ya haifar da abin kunya, kuma an binciki mawallafinsa a matsayin mai gargajiya. Daya daga cikin manyan abubuwan da suka ki amincewa da ka'idar Darwin shine cewa ya nuna babu wani bambanci tsakanin mutane da dabbobi "kasa", a cewar Darwin mutane sun dan samu sauki ne fiye da sauran halittu kamar lemurs, birai da sauran birai. A lokacin, a lokacin wannan ra'ayin ya saba wa ka'idojin addini na asali.
Duk da haka, An tallafawa Darwin sosai ta wani muhimmin rukuni na masana kimiyya na lokacin. Tunanin Darwin yayi nasara kuma daga karshe ya sami karbuwa sosai. A yau sanannen ra'ayi ne cewa mutumin zamani (homo sapiens) ya samo asali ne daga magabata irin na biri.
Zabin yanayi
Matsalar karatun zabin da juyin halittar halitta a cikin mafi yawancin jinsin halittu ya ta'allaka ne akan yanayin yadda tsarin yake tafiya a hankali. Koyaya, wasu halaye da suka shafi yuwuwar rayuwa na iya canzawa cikin sauri: juyin halitta ba lallai bane ya ɗauki dubban shekaru. Misali, jinsunan da ke fuskantar barazanar dabbobi suna iya canzawa cikin sauri, ta zabin yanayi, don rage barazanar kamawa.
Zaɓin yanayi shine mafi sauƙin nazarin kwayoyin halitta tare da gajeren zamani. Kwayar cuta, alal misali, tana iya samun lokacin tsararraki na mintuna 20 kawai, don haka zabin yanayi na iya samar da canje-canje masu mahimmanci a cikin wadannan kwayoyin a cikin dan kankanin lokaci.
Ka'idar zamani
Yanayin zamani na ka'idar Darwin, cigaban-Darwiniyancin, wanda aka fi sani da kira na zamani ko kuma ka'idar roba, ya hade ilimin karni na XNUMX a cikin kwayoyin halittar gado da kuma bangarorin da suka danganci tunanin na Darwin. Bincike kan yadda kwayoyin halitta ke nunawa a cikin jama'a na kwayoyin kuma karatun yanzu game da juyin halitta ya sake tabbatar da mahimmancin zabin yanayi. A cikin burbushin halittu, wannan tsarin na roba ya samar da bayanai game da tsarin juyin halittar halitta akan lokacin ilimin kasa.