Masanan juyin halitta sun ba da rahoton cewa sun hada binciken PET na tattabarai na zamani tare da nazarin burbushin dinosaur don taimakawa wajen amsa tambaya mai dorewa a ilmin halitta: Ta yaya kwakwalwar tsuntsaye ta samu don ba su damar tashi?
Tsuntsu - hoto mai kwatanta. Darajar hoto: Pixabay (Lasin Pixabay Kyauta)
Amsar ta bayyana a matsayin karuwa mai daidaitawa a cikin girman cerebellum a wasu burbushin kashin baya. Cerebellum yanki ne a bayan kwakwalwar tsuntsu wanda ke da alhakin motsi da sarrafa motar.
An buga sakamakon binciken a cikin mujallar Ayyukan Royal Society B.
"Mun gano cewa lokacin da tsuntsaye ke canzawa daga hutawa zuwa tashi, ana kunna da'irori a cikin cerebellum fiye da kowane bangare na kwakwalwa," in ji marubucin binciken. Paul Gignac, Mataimakin Farfesa a Jami'ar Arizona Kwalejin Medicine - Tucson, nazarin neuroanatomy da juyin halitta. Shi ma abokin bincike ne na Gidan Tarihi na Tarihin Halitta na Amurka.
"Sai kuma muka kalli kwanyar da ta yi daidai da wannan yanki a cikin dinosaur da burbushin tsuntsaye don gano lokacin da cerebellum ya karu," in ji Gignac. "Bugu da ƙari na farko ya faru ne kafin dinosaurs su ɗauki reshe, wanda ke nuna cewa jirgin saman jiragen sama yana amfani da tsohowar da aka kiyaye sosai, amma tare da matakan ayyuka na musamman."
Masana kimiyya sun dade suna tunanin cewa cerebellum ya kamata ya zama mahimmanci a cikin jirgin tsuntsaye, amma sun rasa shaidar kai tsaye. Don nuna kimarsa, sabon binciken ya haɗa bayanan hoton PET na zamani na ƴan tattabarai na yau da kullun tare da tarihin burbushin halittu, nazarin yankunan kwakwalwar tsuntsaye a lokacin jirgin da kuma kwakwalen tsohuwar dinosaur. Binciken PET yana nuna yadda gabobin jiki da kyallen takarda ke aiki.
"Tsarin jirgin sama tsakanin kashin baya wani lamari ne da ba kasafai ba a tarihin juyin halitta," in ji jagorar marubuci Amy Balanoff, daga Makarantar Magunguna ta Jami'ar Johns Hopkins.
A gaskiya ma, kawai ƙungiyoyi uku na vertebrates, ko dabbobi masu kashin baya, sun samo asali ne don tashi: bacewar pterosaurs - ta'addanci na sama a lokacin Mesozoic, wanda ya ƙare fiye da shekaru 65 da suka wuce - jemagu da tsuntsaye, in ji Balanoff. Ƙungiyoyin tashi uku ba su da alaƙa ta kud da kud akan bishiyar juyin halitta, kuma mahimman abubuwan da suka ba da damar tashi a cikin ukun ba su da tabbas.
Bayan daidaitawar jiki na zahiri don tafiya, kamar dogayen gaɓoɓi na sama, wasu nau'ikan gashin fuka-fukai, gyare-gyaren jiki da sauran abubuwa, ƙungiyar ta tsara bincike don gano abubuwan da suka haifar da kwakwalwar da ke shirin tashi.
Don yin haka, ƙungiyar ta haɗa da injiniyoyin kimiyyar halittu a Jami'ar Stony Brook da ke New York don kwatanta aikin kwakwalwar kuɗaɗen zamani kafin da bayan jirgin.
Masu binciken sun yi binciken PET don kwatanta ayyukan a yankuna 26 na kwakwalwa lokacin da tsuntsu ya huta kuma nan da nan bayan ya tashi na minti 10 daga wannan perch zuwa wani. Sun leka tsuntsaye takwas a ranaku daban-daban. Binciken PET yana amfani da wani fili mai kama da glucose wanda za'a iya bin sa zuwa inda ƙwayoyin kwakwalwa suka fi shanye shi, yana nuna ƙarin amfani da kuzari don haka aiki. Mai bin diddigin yana raguwa kuma yana fitar da shi daga jiki cikin kwana ɗaya ko biyu.
Daga cikin yankuna 26, yanki ɗaya - cerebellum - yana da haɓaka mai mahimmanci a cikin matakan ayyuka tsakanin hutawa da tashi a cikin duk tsuntsaye takwas. Gabaɗaya, matakin ƙara yawan aiki a cikin cerebellum ya bambanta sosai, idan aka kwatanta da sauran sassan kwakwalwa.
Masu binciken sun kuma gano karuwar ayyukan kwakwalwa a cikin abin da ake kira hanyoyin kwarara na gani, hanyar sadarwa na sel kwakwalwa da ke haɗa kwayar ido a cikin ido zuwa cerebellum. Waɗannan hanyoyin suna aiwatar da motsi a cikin filin gani.
Balanoff ya ce binciken da kungiyar ta samu na karuwar ayyukan a cikin cerebellum da hanyoyin kwararar gani ba lallai ba ne, tunda an yi hasashen wuraren da za su taka rawa a cikin jirgin.
Wani sabon abu a binciken nasu shi ne danganta binciken cerebellum na kwakwalwar da ke da ikon tashi a cikin tsuntsayen zamani da tarihin burbushin halittu wanda ya nuna yadda kwakwalwar dinosaur irin tsuntsaye suka fara bunkasa yanayin kwakwalwar tashi.
Don yin haka, ƙungiyar ta yi amfani da bayanan da aka ƙirƙira na endocasts, ko gyare-gyare na sararin ciki na kwanyar dinosaur, wanda, idan ya cika, yayi kama da kwakwalwa.
Daga nan sai suka gano tare da gano wani babban haɓakar ƙarar cerebellum zuwa wasu farkon nau'ikan dinosaur na maniraptoran, waɗanda suka riga sun fara bayyanar da jirgin sama mai ƙarfi a tsakanin dangin tsuntsu, gami da. Archaeopteryx, dinosaur mai fuka-fuki.
Masu binciken da Balanoff ya jagoranta kuma sun sami shaida a cikin ƙwaƙƙwaran haɓakar haɓakar nama a cikin cerebellum na farkon maniraptorans, nunin ƙara rikitarwar kwakwalwa.
Masu binciken sun yi gargadin cewa waɗannan bincike ne na farko, kuma ayyukan kwakwalwa suna canzawa yayin tashin jirgin da ke da ƙarfi kuma na iya faruwa yayin wasu halaye, kamar su gudu. Sun kuma lura cewa gwaje-gwajen nasu sun haɗa da tashi kai tsaye, ba tare da cikas ba kuma tare da hanyar jirgin sama mai sauƙi, kuma sauran sassan kwakwalwa na iya yin aiki sosai yayin tukin jirgin.
Ƙungiyar binciken tana shirin gaba da nuna madaidaitan wurare a cikin cerebellum waɗanda ke ba da damar kwakwalwar da ke shirye-shiryen jirgin da haɗin gwiwar jijiyoyi tsakanin waɗannan sifofi.
Ka'idodin kimiyya don dalilin da yasa kwakwalwa ke girma a cikin tarihin juyin halitta sun haɗa da buƙatar ratsa sabbin wurare daban-daban, saita matakan tashi da sauran salon motsi, in ji marubucin marubuci Gabriel Bever na Makarantar Magungunan Jami'ar Johns Hopkins.
Sauran marubutan binciken sun hada da Elizabeth Ferrer na Cibiyar Tarihin Tarihi ta Amirka da Jami'ar Samuel Merritt; Lemise Saleh da Paul Vaska na Jami'ar Stony Brook; M. Eugenia Gold na Cibiyar Tarihi ta Tarihi ta Amirka da Jami'ar Suffolk; Yesus Marugán-Labana Jami'ar Madrid mai cin gashin kansa; Mark Norell na Gidan Tarihi na Tarihin Halitta na Amirka; David Ouellette na Kwalejin Kiwon Lafiya ta Weill Cornell; Michael Salerno na Jami'ar Pennsylvania; Akinobu Watanabe na Cibiyar Tarihi ta Tarihi ta Amirka, Cibiyar Fasaha ta New York College of Osteopathic Medicine and Natural History Museum of London; da Shouyi Wei na Cibiyar Proton New York.
Cibiyar Kimiyya ta Kasa ce ta dauki nauyin wannan binciken.
Source: Jami'ar Arizona
