Zamanin Paleozoic yana da kimanin lokaci shida kuma ɗayansu shine Lokacin Ordovician. Yana daya daga cikin lokutan da ake samunsu kai tsaye bayan Lokacin Cambrian kuma kafin Lokacin Silurian. An bayyana shi musamman ta hanyar haɓaka matakan teku wanda ya haifar da yaduwar rayuwar halittu da halittu masu rai. Da Fauna na Ordovician tana da raguwar rabe-raben halittu masu yawa a karshen lokacin sakamakon faruwar al'amarin.
A cikin wannan labarin zamu gaya muku duk abin da kuke buƙatar sani game da faretin Ordovician da mahimmancinsa.
Halaye na zamanin Ordovician
Kafin sanin dabbobin da suka mamaye dabbobi na Ordovician, zamu san menene halaye na wannan lokacin. Ya ɗauki kimanin shekaru miliyan 21 tare da mahimmancin bambancin yanayi tsakanin farkon sa da ƙarshen sa. A farkon lokacin akwai yanayi mai tsananin zafi, amma yayin wucewa tare da jerin sauye-sauyen muhalli, yanayin zafin ya ragu sosai. Tana da lokacin kankara.
Ofaya daga cikin halayen da zamanin Ordovician yayi fice shine aukuwar lamarin wanda ya shafe kashi 85% na nau'in halittu masu rai, musamman tsarin halittun ruwa. Game da ilimin geology na zamanin Ordovician, zamu ga cewa an raba duniya zuwa manyan kasashe 4: Gondwana (mafi girma duka), Siberia, Laurentia da Baltic. Burbushin da aka samo daga duwatsu daga wannan lokacin yana da duwatsu masu yawa.
Game da yanayi kuwa mun ga yana da dumi da kuma yanayi mai zafi a farko. Wasu zafin jiki sun kai darajar darajoji 60 a ma'aunin Celsius. Koyaya, a ƙarshen wannan lokacin yanayin yanayin ya ragu ta yadda akwai mahimmin glaciation. Wannan kyalkyali ya fi shafar nahiyar ta Gondwana. A wancan lokacin, wannan nahiya tana kudu da duniya. Abubuwan da ke haifar da glaciation har yanzu ba a san su ba, amma da yawa suna magana game da raguwar ƙwayoyin carbon dioxide. Har yanzu ana ci gaba da karatu don gano musabbabin hakan.
Rayuwar Ordovician
A lokacin Ordovician akwai babban rashi rayuwa. Musamman wanda ke rayuwa a cikin teku ya ɓullo. Za mu yi takaitaccen nazari kan fulawar Ordovician. La'akari da cewa kusan duk rayuwa ta bunkasa a mazaunin ruwa, yana da mahimmanci a lura da hakan akwai wakilai daga masarautar Plantae galibi wasu daga masarautar Fungi.
Koren algae ya yadu a cikin tekuna kuma akwai wasu nau'ikan fungi wadanda suka cika aikin kamar yadda yake a kowane tsarin halittu: don bazuwar da wargaza matattun kwayoyin halitta. Da kyar aka samu wasu tsarukan halittu na duniya tare da shuke-shuke, kodayake wasu kananun sun fara mallakar kasashen yankin. Waɗannan tsirrai ne na asali waɗanda ba na jijiyoyin jini ba. Bai ma da tsarin xylem da phloem ba. Saboda wannan, dole ne su kasance kusa da ruwa don samun wadatar wannan albarkatu.
Fauna na Ordovician
Zamu bayyana menene fauna na Ordovician da ainihin halayensa. Dole ne a jaddada cewa fauna Ordovician sunada yawa sosai a cikin teku. Akwai dabbobin da yawa daban-daban tun daga kanana da na zamanin baya zuwa wadanda suka fi rikitarwa da hadaddun.
Za mu fara da arthropods. Yana da wadataccen yanki a lokacin Ordovician. A cikin wakilan wannan gefen zamu iya ambaton abubuwan da ake kira brachiopods, trilobites da kunamai na ruwa. Waɗannan suna da samfuran samfuran da yawa da keɓaɓɓu a cikin tekun wannan lokacin. Hakanan akwai wasu nau'in crustaceans.
Game da mollusks, sun sami babban fadada akan juyin halitta. A cikin wasu tekuna akwai nautiloid cephalopods, bivalves da gastropods. Gastropods sun ƙaura zuwa gaɓar teku, amma dole ne su dawo da zama cikin mazaunin ruwa kamar yadda suke da numfashi na gill. Wannan gaskiyar ba ta nuna cewa za a iya tarwatsa su a duk cikin mazaunin duniya ba. Kodayake kifi ya wanzu tun daga Cambrian, kifi mai laushi kamar coccosteus ya fara bayyana yayin fauna na Ordovician.
Ba a yaba da murjani ba shi kaɗai, amma sun fara haɗuwa. A wannan lokacin an ƙirƙiri farkon farkon murjani. Wasu nau'in sponges sun riga sun bambanta daga lokacin da ya gabata.
Kawar da dabbobin Ordovician
Kamar yadda muka ambata a baya, daya daga cikin siffofin da suka yi fice a wannan lokaci shine daya daga cikin halaye wadanda suka shafe kashi 85% na dabbobin da suke a wannan lokacin. Ya faru kusan shekaru miliyan 444 da suka gabata tare da iyakar lokacin Ordovician da Silurian. Kwararru zasu iya yin zato game da dalilin da ya sa wannan bacewar ta faru. Mai yiwuwa ne saboda canje-canje a cikin yanayin muhalli da ake samu a wancan lokacin. Misali, shine ke da alhakin halakarwa raguwar iskar carbon dioxide na yanayi. Wannan ya ba da gudummawa ga raguwar iskar gas da gudummawarta ga tasirin yanayi. Sakamakon haka, an sami raguwar yanayin zafin muhalli a duniya.
Wannan raguwar yanayin zafin ya haifar da zamanin kankara wanda yafi shafar manyan yankuna Gondwana. A cikin glaciation kawai ƙananan kashi ne na jinsunan suka rayu. Wani dalili kuma da yasa masana kimiyya sukayi imani cewa akwai halaka mai yawa shine raguwar matakan teku. Wannan aikin ya faru ne saboda kusancin manyan talakan ƙasar da suka wanzu a lokacin. Wannan ya haifar da rufe tekun Lapetus gabaɗaya. Tunda yawancin nau'ikan da ke akwai sun kasance a cikin mazaunin teku, hakan ya haifar ko ƙarancin yawancin su.
Yin annashuwa shine babban abin da ya haifar da kyakkyawan halaye. An yi imanin cewa yana da alaƙa da raguwar iskar carbon dioxide. Waɗanda suka rayu sun sami damar daidaitawa zuwa raguwar yanayin zafin jiki da canje-canje a cikin yanayin muhalli. Dalilin karshe da yasa masana kimiyya suke tunanin bacewar shine saboda fashewar wani abu mai karfin gaske. Wannan ka'idar an kirkireshi ne a cikin shekaru goma na farko na karni na XNUMX kuma yana cewa dalilin shine cewa fashewar supernova a sararin samaniya. Wannan ya haifar da duniya da ambaliyar gamma daga fashewa.
Ina fatan cewa tare da wannan bayanin zaku iya koyo game da fauna na Ordovician.