Za ku shiga wani kori mai haske, inda za ku haɗu da marasa galihu waɗanda ke shan azaba da azaba. Amma ba za su sami kwanciyar hankali a nan ba, domin a bayan kowane ƙofofin yana jiran su har ma da azaba da tsoro, cike da dukan sel na jiki da cika duk tunani. Za ka kusanci ɗaya daga cikin kofofin, a bayanta za ka ji motsi na jahannama da ƙugiya mai sanyaya kai ga kashi. Tattara sauran ƙarfin halinka cikin hannu, ka miƙa hannunka, sanyi da firgita, zuwa ga hannun ƙofar, ba zato ba tsammani wani ya taɓa kafadarka daga baya, kuma kai, da mamaki da mamaki, juya. “Likitan zai samu ‘yanci nan da ‘yan mintoci kadan. Zauna a yanzu, za mu kira ka, "muryar jinya ta gaya muku. A fili wannan shine yadda wasu suke tunanin zuwa likitan hakori, waɗanda ke da mummunan hali ga waɗannan "masu bakin ciki" a cikin fararen tufafi. Amma a yau ba za mu yi magana game da dentophobia ba, za mu yi magana game da crocodiles. Ee, a, game da su ne, ko kuma daidai game da hakoransu, waɗanda ba sa buƙatar magani na haƙori.
Masana kimiyya daga Jami'ar Missouri (Amurka) sun gudanar da wani bincike na hakora na kada, wanda ya nuna siffofi masu ban sha'awa na enamel na wadannan mafarauta marasa kyau, suna dogara daidai da muƙamuƙi. Menene masana kimiyya suka gano, ta yaya hakoran kada na zamani suka bambanta da danginsu na tarihi, kuma menene amfanin wannan bincike? Mun koyi game da wannan daga rahoton ƙungiyar bincike.
Tushen bincike
Ga mafi yawan kashin baya, hakora sifa ce mai mahimmanci ta samun da cin abinci (magungunan anteaters ba sa ƙidaya). Wasu mafarauta sun dogara da gudu lokacin farauta (cheetahs), wasu a cikin tawagar (zakuna), wasu kuma, ƙarfin cizon su yana taka rawar gani sosai. Wannan kuma ya shafi kada, wadanda ke latsawa kan wadanda abin ya shafa a cikin ruwa su kama su da muƙamuƙi masu ƙarfi. Don hana wanda aka azabtar da shi daga tserewa, kullun dole ne ya kasance mai ƙarfi, kuma wannan yana haifar da nauyi mai nauyi akan tsarin kashi. Don kawar da mummunan tasirin cizon su masu ƙarfi, crocodiles suna da ɓangarorin kashi na biyu, wanda aka haɗa shi da kwanyar.
Nuni na gani na rufewa da buɗe muƙamuƙin kada.
Daya daga cikin manyan abubuwan da ke tattare da hakoran kada shi ne maye gurbinsu akai-akai da sababbi idan tsofaffin suka kare. Gaskiyar ita ce, haƙoran crocodiles sun yi kama da ɗan tsana, wanda a cikinsa sababbin hakora ke tasowa. Kusan sau ɗaya a kowace shekara 2, kowane hakora a cikin muƙamuƙi ana maye gurbinsu da sababbi.
Yi la'akari da yadda wannan "tarkon hakori" ke rufe sosai.
Hakoran kada sun kasu kashi-kashi da yawa bisa la'akari da siffa da aikin da ya dace. A farkon muƙamuƙi akwai manyan fangs guda 4, waɗanda ake buƙata don kama ganima mai inganci. A tsakiyar akwai hakora masu kauri, waɗanda ke ƙaruwa tare da muƙamuƙi. Ana buƙatar wannan ɓangaren don yankan ganima. A gindi, hakora suna faɗaɗa kuma su zama masu faɗi, wanda ke ba wa crocodiles damar cizo ta cikin bawo na mollusk da harsashi kunkuru kamar tsaba.
Yaya ƙarfin muƙarƙashin kada? A zahiri, wannan ya dogara da girmansa da nau'insa. Misali, a shekara ta 2003 an gano cewa, 272-kilogram Mississippi alligator cizon da karfin ～9500 N (N - Newton, 1 N = 1 kg m/s2). Amma kada ruwan gishiri mai nauyin kilogiram 1308 ya nuna mai busa hankali ～34500 N. Af, cikakken karfin cizo a cikin mutane ya kai kusan 1498 N.
Ƙarfin cizon ya dogara ba kawai akan hakora ba, amma akan tsokoki na jaw. A cikin kada waɗannan tsokoki suna da yawa sosai kuma akwai da yawa daga cikinsu. Duk da haka, akwai bambanci mai ƙarfi tsakanin tsokoki masu tasowa da ke da alhakin rufe baki (wanda ke ba da irin wannan karfin cizon) da kuma raunin tsoka da ke da alhakin bude baki. Wannan yana bayyana dalilin da yasa za a iya riƙe bakin rufaffiyar kada a wuri tare da tef mai sauƙi.
Kazo ka nuna min wanda ya kira ka dan iska.
Amma kadawa suna buƙatar muƙamuƙi ba kawai don kashe-kashen rashin tausayi don abinci ba, har ma don kula da 'ya'yansu. Kadan mata sukan dauki 'ya'yansu a cikin muƙamuƙi (yana da wuya a sami wuri mafi aminci a gare su, saboda wanda zai so hawa can). Bakin crocodiles yana sanye da masu karɓa masu mahimmanci, godiya ga abin da za su iya daidaita ƙarfin cizon su, wanda ke ba su damar riƙe ganima ko ɗaukar jarirai a hankali.
Haƙoran ɗan adam, da rashin alheri, ba sa girma baya bayan tsofaffi sun fadi, amma suna da wani abu da ya dace da crocodiles - enamel.
Hoto #1: Caudal hakori na Alligator misssippiensis.
Enamel shine harsashi na waje na kambi na hakori. Ita ce bangaren da ya fi karfi a jikin dan Adam, da kuma sauran kasusuwa da dama. Duk da haka, kamar yadda muka sani, haƙoranmu ba sa canzawa don sababbi, saboda haka enamel ɗinmu dole ne ya kasance mai kauri. Amma a cikin crocodiles, tsofaffin hakora ana maye gurbinsu da sababbi, don haka babu buƙatar enamel mai kauri. Yana da ma'ana sosai, amma da gaske haka ne?
Masana kimiyya sun ce fahimtar canje-canje a cikin enamel a cikin haraji ɗaya zai ba mu damar tunawa da kyau a nan gaba yadda tsarin enamel ke canzawa dangane da kwayoyin halitta da kuma abincin dabba.
Kada, wato Mississippiensis alligator, sun dace da wannan binciken don dalilai da yawa. Na farko, haƙoransu, ƙarfin cizon su da tsarin enamel suna canzawa dangane da shekaru da girman mutum, wanda kuma saboda canje-canjen abinci. Na biyu, hakoran kada suna da nau'ikan halittu daban-daban dangane da matsayinsu a cikin muƙamuƙi.
Hoto mai lamba 2: a da b suna nuna banbancin hakora tsakanin manya da kanana, c-f yana nuna hakoran kakannin kakanni na crocodiles na zamani.
Haƙoran rostral suna da bakin ciki kuma ana amfani da su don kama ganima, yayin da haƙoran caudal ba su da ƙarfi kuma ana amfani da su don murkushe manyan cizo. Wato nauyin da ke kan hakori ya dogara da matsayinsa a cikin muƙamuƙi da kuma girman mai wannan muƙamuƙi.
Wannan binciken yana gabatar da sakamakon bincike da ma'auni na cikakkar kauri na enamel (AET) da madaidaitan girman (dangi) kauri na enamel (RET) na haƙoran kada.
AET kimanta matsakaicin nisa daga mahaɗar enamel-dentin zuwa saman enamel na waje kuma ma'aunin layi ne. Kuma RET ƙima ce marar girma wacce ke ba ku damar kwatanta kauri na enamel a ma'auni daban-daban.
Masana kimiyya sun tantance AET da RET na rostral (a "hanci" na jaw), matsakaici (a tsakiyar jere) da caudal (a gindin jaw) hakora a cikin mutane bakwai na nau'in. Mississippiensis alligator.
Har ila yau, yana da mahimmanci a lura cewa tsarin enamel zai iya dogara ne akan abincin mutum da nau'in gaba ɗaya. Kadan na da yawan abinci mai yawa (abin da suke kamawa shine abin da suke ci), amma ya sha bamban da na ’yan uwansu, wadanda suka dade da bacewa. Don gwada wannan ta fuskar enamel, masana kimiyya sun gudanar da nazarin AET da RET na burbushin. Protosuchidae (UCMP 97638), Iharkutosuchus (MTM VER 2018.837) da Allognathosuchus (YPM-PU 16989). Protosuchidae shi ne wakilin Jurassic lokacin, Iharkutosuchus - lokaci na Cretaceous, da kuma Allognathosuchus daga Eocene.
Kafin fara ainihin ma'auni, masu binciken sunyi tunani kuma sun ba da shawarar hasashe da yawa:
- Hasashen 1a-Saboda AET ma'auni ne na madaidaiciya kuma yakamata ya dogara da girman, bambance-bambance a cikin AET ana tsammanin za a bayyana shi da girman kwanyar;
- Hasashen 1b-Saboda an daidaita RET da girman, ana sa ran bambance-bambance a cikin RET za a bayyana shi mafi kyau ta matsayi na hakori;
- Hasashen 2a-Saboda AET da tsawon kwanyar su ne ma'auni na girman kai, ya kamata su yi ma'auni tare da gangaren isometric;
- Hasashen 2b - Saboda haƙoran caudal sun sami mafi girman ƙarfin cizo a cikin baka, saboda haka RET zai kasance mafi girma a cikin haƙoran caudal.
Teburan da ke ƙasa suna ba da bayanan samfurin (kwayoyin crocodiles Mississippiensis alligator, wanda aka karɓa daga Rockefeller Reserve a Grand Chenier, Louisiana, da burbushin halittu).
Tebur No. 1: bayanan binciken haƙoran kada (rostral, matsakaici da caudal).
Tebur No. 2: bayanan hakori (LSkull - tsayin kwanyar, hCrown - tsayin rawanin, VE - ƙarar enamel, VD - ƙarar dentin, SAEDJ - yankin ƙirar enamel-dentin, AET - cikakkiyar kauri na enamel, RET - kauri enamel dangi).
Sakamakon bincike
Dangane da bayanan hakori da aka gabatar a cikin Table 2, masana kimiyya sun kammala cewa enamel kauri ma'auni isometrically tare da tsawon kwanyar, ba tare da la'akari da matsayin hakori ba.
Tebur No. 3: ƙimar AET da RET dangane da masu canji.
Hoto #3: Sikelin AET/RET dangane da tsawon kwanyar.
A lokaci guda, kauri na enamel akan hakoran caudal ya fi girma fiye da sauran, amma wannan kuma baya dogara da tsawon kwanyar.
Table No. 4: matsakaicin darajar enamel kauri a cikin mafi girma vertebrates (Crocodyliform - karin-taxon kungiyar crocodiles, Dinosaur - dinosaurs, Artiodactyl - artiodactyls, Odontocete - suborder na cetaceans, Perissodactyl - m-toed ungulates, Primate - primate - Rodent - rodents).
Hoto #4: Kauri na enamel na hakora caudal ya fi na sauran hakora.
Bayanai game da sikelin (Table No. 3) sun tabbatar da hasashe na 1a, yana bayanin dogara ga darajar AET akan tsawon kwanyar, kuma ba akan matsayi na hakori ba. Amma ƙimar RET, akasin haka, sun dogara ne akan matsayin hakori a jere, kuma ba akan tsayin kwanyar ba, wanda ya tabbatar da hasashe 1b.
Sauran ra'ayoyin (2a da 2b) su ma an tabbatar da su, kamar haka daga nazarin matsakaicin kauri na enamel na hakora tare da matsayi daban-daban a jere.
Kwatanta kaurin enamel na zamani na Mississippi alligator da kakanninsa sun nuna kamanceceniya da yawa, amma kuma akwai bambance-bambance. Don haka, a cikin Allognathosuchus kauri na enamel yana da kusan 33% girma fiye da na crocodiles na zamani (hoton da ke ƙasa).
Hoto #5: Kwatankwacin matsakaicin kaurin enamel a cikin alligator da burbushin crocodylian bisa tsayin kambin hakori.
Taƙaice duk bayanan da ke sama, masana kimiyya sun yanke shawarar cewa kauri na enamel kai tsaye ya dogara da, don yin magana, aikin hakora. Idan ana buƙatar waɗannan haƙoran don murƙushewa, enamel ɗin su zai yi kauri sosai. A baya an gano cewa matsa lamba (matsa lamba) na hakora caudal ya fi na haƙoran rostral. Wannan ya faru daidai da rawar da suke takawa - don riƙe ganima da murkushe ƙasusuwa. Don haka, enamel mai kauri yana hana lalacewar hakora, waɗanda ke ƙarƙashin matsakaicin matsakaici yayin abinci mai gina jiki. Tabbas, shaidu sun nuna cewa haƙoran caudal a cikin crocodiles suna karya da yawa akai-akai, duk da tsananin damuwa.
Bugu da kari, an gano cewa hakora Allognathosuchus enamel yana da kauri sosai fiye da na sauran crocodylyan da aka yi nazari. An yi imanin cewa wannan nau'in burbushin halittu sun fi son ciyar da kunkuru, kuma murkushe bawonsu na bukatar hakora masu kauri da kaurin enamel.
Masana kimiyya sun kuma kwatanta kaurin enamel na crocodiles da wasu dinosaur, daidai da kiyasin nauyi da girmansa. Wannan bincike ya nuna cewa crocodylian suna da enamel mai kauri (hoton da ke ƙasa).
Hoto #6: Kwatanta kaurin enamel na crocodiles da dinosaurs.
Yana da ban sha'awa cewa enamel na tyrannosaurid ya kusan kusan kauri ɗaya da na Allognathosuchus da yawa har ma da crocodiles na zamani. Yana da ma'ana cewa tsarin haƙori na kada yana bayyana ta dabi'arsu ta fuskar farauta da abinci.
Duk da haka, duk da bayanansu, enamel na archosaurs (crocodiles, dinosaurs, pterosaurs, da dai sauransu) ya fi na dabbobi masu shayarwa.
Hoto #7: Kwatanta kauri na enamel (AET) na crocodiles da wasu nau'ikan dabbobi masu shayarwa.
Me ya sa enamel na mafarauta, waɗanda suka dogara da muƙamuƙansu, ya fi na dabbobi masu shayarwa sirara? Amsar wannan tambayar ta riga ta kasance a farkon - maye gurbin sawa hakora da sababbi. Duk da cewa crocodiles suna da hakora masu ƙarfi, amma ba sa buƙatar, don haka a ce, hakora masu ƙarfi, saboda gaskiyar cewa sabon haƙori koyaushe zai maye gurbin wanda ya karye. Dabbobi masu shayarwa (a mafi yawancin) ba su da wannan baiwar.
Hoto #8: Kwatanta kaurin enamel (RET) na crocodiles da wasu nau'ikan dabbobi masu shayarwa.
Mafi daidai, kauri na enamel a cikin archosaurs ya bambanta daga 0.01 zuwa 0.314 mm, kuma a cikin dabbobi masu shayarwa daga 0.08 zuwa 2.3 mm. Bambancin, kamar yadda suke faɗa, a bayyane yake.
Don ƙarin cikakkun bayanai game da nuances na binciken, Ina ba da shawarar yin kallo
Epilogue
Hakora, ko ta yaya baƙon sauti, kayan aiki ne mai mahimmanci wajen samun abinci. Haka ne, mutum na zamani zai iya gyara duk wani lahani da ke hade da hakora, amma a cikin wakilan daji babu likitocin hakora. Ko da yaushe mutane ba su san menene maganin hakori ba. Saboda haka, wasu nau'ikan suna zaɓar hakora masu ƙarfi da dorewa, yayin da wasu sun fi son canza su, kamar safofin hannu. Ana iya rarraba kada da danginsu na nesa zuwa rukuni biyu. Enamel a kan hakora, waɗanda ke da mahimmanci don riƙe ganima da murkushe ƙasusuwa, yana da kauri sosai a cikin crocodiles, amma idan aka yi la'akari da tsananin damuwa, haƙoran su har yanzu suna lalacewa kuma wani lokacin suna karye. A irin waɗannan lokuta, sabon haƙori ya ɗauki wurin tsohon haƙori.
Ga mutum ɗaya daga cikin abubuwan da ke bambanta shi ne babban yatsan yatsan hannu, wanda ya taimaka mana sosai a cikin yunƙuri da yawa, tun daga “ɗaukar sanda ka lalata maƙwabci mai ban haushi a reshe” kuma ya ƙare da “ɗaukar alkalami ka rubuta sonnet. ” Ga crocodiles, irin wannan kayan aiki shine jaws, musamman hakora. Wannan sashe na jiki ne ke sanya kada mafarauta masu hatsari da kashe mutane da ya kamata a guje su.
Ranar juma'a:
Wani ɗan gajeren zane mai ban sha'awa da kyan gani mai kyau wanda kada a cikinsa ba shi da kyan gani.
Wani zane mai ban dariya game da yadda ba za ku iya amincewa da "girgije" masu banƙyama a cikin ruwa ba, musamman ma idan kun kasance wildebeest.
Godiya da kallon, tsaya sha'awar kuma sami kyakkyawan karshen mako kowa! 🙂
Na gode da kasancewa tare da mu. Kuna son labaran mu? Kuna son ganin ƙarin abun ciki mai ban sha'awa? Goyon bayan mu ta hanyar ba da oda ko ba da shawara ga abokai, Rangwamen 30% ga masu amfani da Habr akan keɓaɓɓen analogue na sabar matakin shigarwa, wanda mu muka ƙirƙira muku: (akwai tare da RAID1 da RAID10, har zuwa 24 cores kuma har zuwa 40GB DDR4).
Dell R730xd sau 2 mai rahusa? Nan kawai a cikin Netherlands! Dell R420 - 2x E5-2430 2.2Ghz 6C 128GB DDR3 2x960GB SSD 1Gbps 100TB - daga $99! Karanta game da
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