Indlela iidinosaur ezaphela ngayo

Indlela iidinosaur ezaphela ngayo Yinto abantu abaninzi kunye noososayensi abazibuza yona. Nangona kunjalo, akwaziwa ngokuthe ngqo, kodwa kukho iithiyori ezininzi ezichatshazelwa ngakumbi luluntu lwezenzululwazi. Iingcamango ezinjalo zisekelwe kubungqina obunokungqina ukubaluleka kwazo. Kodwa mininzi imibuzo engekaphendulwa ngalo mbandela.

Kweli nqaku siza kukuxelela ukuba zeziphi iithiyori eziphambili malunga nendlela iidinosaur ezaphela ngayo.

Indlela iidinosaur ezaphela ngayo

Iidayinaso zibe zezona zilwanyana zikhulu ezinxulumene nezirhubuluzi eMhlabeni. Zijongwa njengodidi lwesirhubuluzi esinegazi elishushu ngaphambili, esinxulumene kodwa sahluke kakhulu kwizirhubuluzi eziphilayo kunye neentaka. Bahlala malunga ne-160 yezigidi zeminyaka, ngexesha leMesozoic, yahlulahlulwe yangamaxesha amathathu: Triassic, Jurassic kunye neCretaceous. Zanyamalala kudala emhlabeni.

Zaphela nini yaye njani iidinosaur? Lo ngomnye weyona mibuzo ixhaphakileyo esele ijikeleze ezi zilwanyana zamandulo. Nangona inzululwazi ibeke umhla kunye nesizathu soku, namhlanje, ngenxa yenkqubela phambili yesayensi, iinkcukacha ezingaphezulu kunye nophando luye lwavela, iingcamango ezininzi ziye zacetywa, kwaye kwezinye iimeko, umhla unokutshintshwa.

Umhla wokuphela kweedayinaso kukholelwa ukuba malunga ne-65 yezigidi zeminyaka eyadlulayo. Kodwa, yeyiphi eyona ngcamango yamkelweyo yokuphela kweedayinaso kwibutho lenzululwazi? Kangangamashumi eminyaka, kuye kwafunyaniswa ukuba impembelelo yeemeteorites okanye ii-asteroids eMhlabeni zinokutshabalalisa ezi zigebenga zilawula ixesha elide. Nangona kunjalo, njengoko sele sikhankanyile, kukho izizathu ezingakumbi zoku, kwaye namhlanje, ezi zithiyori ezinokwenzeka:

• imeteorite okanye asteroid
• Umsebenzi wentaba-mlilo
• Utshintsho lwemozulu

Ithiyori yemeteorite ekuphelisweni kweedinosaurs

Phakathi kokuphela kweminyaka yee-1970 kunye nasekuqaleni kweminyaka yee-1980, i-meteorite ye-12-kilometer-diameter-diameter okanye i-asteroid eyabetha uMhlaba, ngokukodwa kwingingqi ye-Yucatan Peninsula yaseMexico, yachazwa ukuba ibangele ukuphela kweedinosaurs.

I-iridium-rich geological layer okanye ukwakheka kuye kwafunyanwa ukuba kwahlala kuwo wonke uMhlaba kwaye kubuyela emva kwixesha lokuphela kobunzima. Le element yekhemikhali ayiqhelekanga ukufumaneka kumhlaba womhlaba, kodwa ikhona kwi magma ngaphakathi eMhlabeni, nakwindlela zakudala kunye neemeteorites ezilele nzulu phantsi komhlaba. Ngenxa yokuba le nto inetyhefu kakhulu kwaye i-radioactive, izazinzulu zikholelwa ukuba emva kwe-meteorite enkulu okanye i-asteroid etyebileyo kwizinto ezibetha kwaye ivelisa izixa ezikhulu zesiqalelo ukusuka kumaleko angaphakathi oMhlaba, izinto zisasazeka kulo lonke iplanethia, isiphelo sobomi eMhlabeni. Izidalwa ezininzi kunye needinosaurs ziye zaphela, kodwa oku kwakungesona sizathu kuphela, ukusabela kwekhonkco kwenzeka.

Umngxuma omkhulu weChicxulub, efunyenwe kwiYucatan Peninsula eMexico, nayo yaqala malunga ne-65 yezigidi zeminyaka eyadlulayo, ngoko ke kukholelwa ukuba yindawo yokufunyanwa kwee-asteroids ezinkulu ezandisa i-iridium layer. Ekugqibeleni yakhokelela kule ntlekele inkulu.

Ngoko ukutshabalala okukhulu kweedayinaso kubangelwe kukubetha kwemeteor eMexico. Nangona kunjalo, yayingeyiyo impembelelo ngokwayo eyaphelisa ubomi babantu abaninzi, kodwa yayinempendulo yekhonkco eyaphelisa ubomi obuninzi emhlabeni.

Iimpendulo ezakhokelela ekufeni kweedayinaso zaba ngolu hlobo lulandelayo:

• Yaba yile mpembelelo eyatshabalalisa iidinosaur kulo mmandla.
• Ugqabhuko-dubulo okanye ukothuka kwamaza okudala impembelelo enkulu kunye nesenzeko kwindawo enkulu yomhlaba, njengetsunami enkulu.
• Ubutyhefu kunye ne-radioactivity ye-iridium kunye nezinye izinto ezikhutshiweyo kumaleko angaphakathi oMhlaba ngenxa ye-ejecta evela kwiimpembelelo zemeteorite.
• Ukunyuka okukhulu kwamaqondo obushushu kubalwe ukuba kuphindwe kaninzi kuneLanga, kwaye yade yabangela imililo amawaka eekhilomitha ukusuka kumthombo wempembelelo.
• Umaleko otyebileyo nobanzi weeminerali kunye nezinye izinto ezenza esibhakabhakeni ngenxa yempembelelo yeejethi zomlilo kunye neegesi. Ubukhulu becala, isibhakabhaka sasigqunywe kwi-gypsum, i-sulfate-containing material eyayigubungela ubuninzi be-peninsula yaseYucatan ngelo xesha. Igypsum iyatshintsha ibe ziisulfate ezinyukela kwiatmosfera ngobuninzi, nto leyo ethintela ukukhanya kwelanga ekufikeni emhlabeni. Ifotosynthesis iyayeka (emhlabeni naselwandle) ngenxa yokuvaleka kwemitha yelanga, iiweb zokutya ziphazamiseka kakhulu, kwaye izilwanyana aziboni kakuhle, nto leyo eyenza kube nzima ukufumana nokutya okuncinci emva kweentsuku ezimbalwa. Ukwehla ngesiquphe (malunga ne-10ºC), ebangela ukuba umhlaba ube ngumkhenkce. Ke, ngenxa yokusabela enye okanye enye, izidalwa zelo xesha zazifa kancinci kancinci kubomi obushiye emhlabeni. Ngokuhamba kwexesha, lo maleko uyanyibilika kwaye ngokuyinxenye uwe phantsi, uvumela ukukhanya kwelanga okwaneleyo ukuba kubuyele ebomini ukuze kuphinde kuvuke abambalwa abasindileyo.

Ithiyori yeentaba-mlilo yayisisizathu sokuphela kweedinosaurs

Enye inkcazo-bungcali exhasa uphando lwezenzululwazi olwenziwayo ukuza kuthi ga ngoku yeyokuba iintaba-mlilo zatshatyalaliswa ziidinosaurs. Kukho ubungqina bokuba, ngomhla wokutshabalala, kwakukho umsebenzi omkhulu wentaba-mlilo owaqhubeka ixesha elide ngaphandle kokuphazamiseka, ngakumbi kwinxalenye yaseIndiya. Inyaniso, udaka oluphuma kolu gqabhuko-dubulo lugubungela ngaphezu kwe-2,6 yezigidi zesikwekhilomitha zeIndiya.

Kukholelwa ukuba intlekele enjalo iya kubulala zonke izilwanyana ezikulo mmandla wesi sijikelezi-langa. Ngaphezu koko, ngenxa ye<em>magma evela ngaphakathi emhlabeni nodaka lwentaba-mlilo olutyebileyo kwi<em>iridium, kunye nothuthu lwentaba-mlilo neegesi ezinetyhefu eziphuma kugqabhuko-dubulo oluqhubekayo, ii<em>dinosaur zanyamalala. Ubunzima bokukhanya kwelanga ukufikelela emhlabeni, ukwanda kweegesi ze-greenhouse kunye netyhefu yomoya (enciphisa i-oksijini) yindibaniselwano egqibeleleyo yokuthintela iintlobo ezininzi ukuba zisinde kweli xesha.

Ithiyori yokutshintsha kwemozulu ekuphelisweni kweedinosaurs

Ekugqibeleni, ithiyori yokugqibela eyamkelwa luluntu lwenzululwazi malunga nokuba kutheni iidinosaurs zanyamalala yile yokutshintsha kwemozulu kwiCretaceous. Kukho ubungqina obuninzi be-paleontological kwi-geological strata kunye neefosili zezilwanyana kunye nezityalo ukuba ikhonkco leentlekele, ezifana iinyikima, amaza kunye nokuhla okuphawulekayo kobushushu, zenzeke ebudeni bamanqanaba okugqibela exesha lee<em>dinosaur, nto leyo eyakhokelela kutshintsho olugqithiseleyo lwemozulu.

Ukongeza, inqanaba lamanzi eMhlabeni lehle kakhulu ngenxa yokuhla okukhulu kobushushu. Enye inkalo lutshintsho olukhulu kwimekobume ngelo xesha, yaye ezi zilwanyana zikhulu azikwazi ukuziqhelanisa nexesha.

Ndiyathemba ukuba ngolu lwazi unokufunda ngakumbi malunga nendlela iidinosaur ezaphela ngayo.