Ubumenyamuntu: Uko abantu batakaje imirizo yabo

Ubuzima

Wari wareba inyuma hawe ngo wibaze aho umurizo wawe wagiye?

Ibyo birumvikana nka byendagusetsa cyangwa ikibazo cy’umwana. Ariko ku bahanaga muri science iki ni ikintu gikomeye.

Mu by’ukuri, niba ku misusire abantu dusa rwose n’inyamaswa z’ibisabantu, kuki zo zifite imirizo ariko twe ntayo?

“Ni ikibazo gifite ishingiro”, nk’uko bivugwa na Bo Xia, umuhanga mu bumenyamuntu bwibanda ku uturemangingo wo muri Grossman School of Medicine muri kaminuza ya New York.

Inyamaswa zo mu moko y’ibisabantu zigira imirizo, bitandukanye n’abantu n’ingagi

Imirizo ishobora kugira akamaro kenshi mu isi y’inyamaswa.

Kuva imirizo yaboneka ku binyabuzima bya mbere, hashize imyaka irenga miliyoni 500, igira akamaro gatandukanye.

Ku mafi, ifasha koga mu mazi. Ku nyoni, mu kuguruka. Ku nyamabera ifasha kuziha kuringanira (equilibre/balance).

Ishobora kuba kandi intwaro yo kwirinda, nko kuri scorpions. Cyangwa se ikimenyetso cyo kuburira, nko ku nzoka z’ubumara zinyegayeza umurizo ukavuga.

Ku bisabantu (primates), umurizo ufasha muri byinshi kandi henshi. Urugero inguge zimwe zo muri Amerika zigira umurizo muremure uzifasha kwihambira cyangwa gufata ibintu mu biti.

Ku nyamaswa nyinshi z’inyamabare nka nyirahuku, umurizo uzifasha kwikiza utuntu runaka, no kugira ‘equilibre’

Ariko umuryango w’inyamaswa bita hominids – uhuriyemo abantu, ingagi, inguge na orangs-outans nta mirizo zigira.

Uko byagenze n’impamvu ni ibibazo byakomeje kwibazwa n’abahanga muri science mu myaka myinshi yashize.

Igisubizo gisa n’ikiri mu ihinduka ry’ingingo riheruka kuvumburwa ryakoze ku turemangingo twatumye inyamaswa z’ibisabantu bito z’ubwoko bita hominines zo zigira imirizo hashize imyaka igera kuri miliyoni 25.

Ikindi, uko guhinduka kuba mu gihe kirekire kuva ku kiragano ujya ku kindi, byagiye bihindura imiterere ya hominines, ibishobora kuba bifitanye isano no kuba abantu bagendesha amaguru.

Bo Xia ati: “Izo [nyamaswa] zose zisa n’izifitanye isano kandi byagiye bibaho mu gihe kimwe no kwihinduranya. Ariko ntituzi neza neza buri ntambwe y’uko byagenze muri uko kwihinduranya.

“Nk’uko mwabitekereza, ibyo ni kimwe mu bintu bikomeye mu kwihinduranya( Evolution), nicyo kitugira abantu.”

Mu kugenzura ibyo, Xia akora kwihinduranya nk’uko ku imbeba.

Yabonye ko imbeba zari zifite imirizo y’ubwoko butandukanye. Imwe yari ifite imigufi naho ku zindi imirizo ntiyakuze na mba.

Abantu n’ibisabantu bafite abasekuru bamwe

Sakwe sakwe? Amaguru n’umurizo habanje iki?

Charles Darwin yari yarabivuze. Ko Homo sapiens (umuntu w’iki gihe mu yandi magambo) akomoka ku nguge z’imirizo.

Uyu muhanga w’Umwongereza mu 1871 yanditse igitabo ku nkomoko y’umuntu, muri cyo asobanuramo ibijyanye no kwihinduranya (evolution) aguhuza n’umuntu w’iki gihe. Byari uguhishura gukomeye icyo gihe.

Ariko n’ubundi, abantu bakomeje gukora itandukaniro hagati y’isi y’inyamaswa n’isi igezweho: tuba mu nzu, uruhu n’ubwoya biratandukanye, kandi dukoresha ubwonko mu gukemura amahurizo akomeye.

Darwin icyo gihe yabirinduye ishingiro rya science y’icyo gihe atangaza igitabo yise ‘Origin of Species’ aho asobanura ko umuntu ava ku ihinduka, kandi abahanga bose b’iburengerazuba icyo gihe baremeraga igitekerezo ko Imana ari yo yaremye abantu, isi n’ibiyiriho.

Nyamara kandi abantu n’ingunge, dusangiye abasokuru, duhuje 98% kuri ADN.

Ndetse na Hominids (umuryango duhururamo) za mbere zabonetse mu myaka ikabakaba miliyoni 20 ishize zikaba nta mirizo zagiraga.

Ishusho ya Charles Darwin, Umwongereza wanditse igitabo “L’origine des espèces” na “L’origine de l’homme”

Rero, niba umurizo ufite ihuriro no guhinduka kw’abantu n’ibisabantu kandi waragize ingaruka ku ngendo (demarche) zabyo, ikibazo kibazwa ni icyaje mbere, umurizo cyangwa amaguru?

Xia ati: “Ni nk’ikibazo cy’igi n’inkoko. Nk’uko mwabyibaza, ntabwo ari ikibazo byoroshye gusubiza.”

Muri macye, ntabwo bishoboka kumenya neza ibyabanje kugira ngo abasokuru bacu bahagarare ku maguru, niba byaratewe n’uko nta mirizo bari bafite.

Cyangwa se niba tudafite imirizo kuko tugenda duhagaze kandi bikaba byoroshye guhagarara twemye ku maguru yacu.

Iyo witegereje cyane, ubona ibintu byinshi ibisabantu bimwe bihuriyeho natwe abantu

Xia ati: “Byasaba imashini yasubiza inyuma ibihe kugira ngo ibyo byose bimenyekane, tukareba ibyabanje. Ariko kuko ntayo dufite, icyo navuga ni uko tutabizi, impaka zigashirira aho. Ariko umuntu akaza kwibaza ati ‘kuki tuvuga ibyo byose’.

“Igisubizo nyacyo ni uko iby’amaguru n’umurizo bigibwaho impaka icya rimwe. Muri macye ntitwavuga kwihinduranya (evolution) ngo ntidukomoze ku murizo no ku maguru abiri, tutitaye ku cyaje mbere.”

Igisubizo kiri mu guhererekanya ibitugize

Kuva yababara akagufa ko ku ruti rw’umugongo (coccyx) ari mu modoka, hashize imyaka ibiri, Xia ntiyigeze areka gutekereza ku ngingo y’imirizo n’abantu.

Coccyx niko kagufa ka nyuma ko hasi ku ruti rw’umugongo, kagizwe n’utugufa tune dufatanye kandi kerekana ishusho y’icyahoze ari umurizo mu myaka miliyoni nyinshi ishize.

Iyo urebye amashusho y’umwana ukiri gutangira kwirema (embryon) mu nda ya nyina, ubona umurizo, uza kugenda nyuma y’ibyumweru bicye mu ikorwa ry’uruti rw’umugongo.

Iyo coccyx, niyo twicarira, iri ahantu neza neza umurizo uba uri ku zindi nyamaswa.

Itai Yanai umushakashatsi mu buvuzi wo muri kaminuza ya New York avuga ko mu myaka 100 ishize science yageze kuri byinshi mu kwiga ibijyanye no guhererekanya ibitugize kw’abantu (génétique).

Ati: “Twibaza ibi bibazo byose kuko abantu bakunda science kandi ari yo bajyaho mu gushaka ibisubizo ku bibazo runaka.”

Kwihinduranya kwabonywe na Xia Bo mu bushakashatsi bwe ku mbeba kwerekana utunyangingo tubarirwa mu magana tuzwi nka TBXT, ako ni agace kagize ADN kandi usanga ari kamwe ku bantu no ku bisabantu.

Mu gusuzuma ihuriro hagati yo kwihinduranya n’umurizo, Xia yahinduye utunyangingo tumwe na tumwe duhererekanywa ku mbeba akoresheje uko kwihinduranya.

Eureka! Xia na bagenzi be bavumbuye ko umurizo w’imbeba utongeye kumera nk’uko byagendaga mbere.

Hari utunyangingo twinshi dutuma inyamaswa zimera umurizo

Ariko ubwo buvumbuzi ni ubwa mbere mu ruhererekane ruzatuma tumenya neza ibyo kwihinduranya kwabaye ku basokuru bacu.

Abahanga muri science bavuga ko hari utunyangingo turenga 30 dutuma inyamaswa zimera umurizo, kandi abashakashatsi b’i New York bo bavuga kamwe.

Nk’uko Xia abivuga, abantu bose bafite amagufa y’umurizo kandi asa, ariko kuri za mbeba zakoreweho ubushakashatsi imirizo yari ifite uburebure butandukanye cyangwa se nta yo na mba.

Umwanzuro wa Xia ni uko habayeho kwihinduranya gutandukanye, aho kuba kumwe, kwahinduye utunyangingo duhererekanywa kuri za hominines mu myaka igera kuri miliyoni 25 ishize maze bigahindura abantu uko tumeze ubu.

Ati: “Birashoboka ko ari ukwihinduranya gukomeye, ariko ntitwibaza ko ari ko gusa kwabiteye.”

Kwihinduranya kwatumye abantu batakaza imirizo kwanahinduye ingendo yabo

Xia na Yanai bavuga ko kwihinduranya gushobora kugira ingaruka mbi, harimo kurwara cyangwa no gupfa.

Ariko kandi kwihinduranya kuzana ibyiza aho gushobora kwakirwa neza n’abo kubayeho maze kugahererekanywa ibiragano ku bindi.

Icyo Xia asobanura ni uko gutakaza imirizo kwazaniye ba hominidis (bwa bwoko duhuriramo n’ibisabantu bidafite imirizo) ibyiza kandi by’ingenzi bisobanura impamvu kwamaze igihe kirekire.

Ati: “Cyane cyane uko abantu bagenda cyangwa uko dukoresha intoki mu gukora ibintu bitandukanye.”

Ariko ibyo ngo ntabwo bisobanuye ko gutakaza imirizo byatuzaniye ibyiza gusa.

Xia n’itsinda rye babonye ko imbeba bakoresheje mu bushakashatsi zagize imiterere mibi ku ruti rw’umugongo isa cyane n’indwara y’umwobo ku ruti rw’umugongo ifata umwana umwe w’umuntu ku bana 1,000 bavutse.

Ubwo busembwa buva ku kitwa spina bifida, kibaho iyo uruti rw’umugongo ruri kwikora ku mwana utaravuka rutifunze neza.

Xia ati: “Sinavuga rero ko kwihinduranya ari byiza cyangwa bibi. Ni ikintu kibaho gutyo gusa.”

Abahanga muri science bamaze kumenya uko twatakaje imirizo ariko ntabwo baramenya neza impamvu

Kuri M.Yanai imirimo y’abashakashatsi izafasha kumva ibintu byabaye mu mateka ya cyera cyane y’abasukuru bacu.

Ati: “Nibaza ko ibyo Bo (Xia) yagezeho bizafasha umuryango w’abahanga muri science kurushaho kugera ku bindi.”

 

 

Src: BBC

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