Ixesha le-Paleozoic lalinamaxesha amathandathu kwaye elinye lawo li Ixesha le-Ordovician. Elinye lamaxesha abekwe kwangoko emva kwe Ixesha leCambrian nangaphambili Ixesha leSilurian. Yayibonakaliswa ikakhulu ngokuba namanqanaba olwandle aphakamileyo abangela ukwanda kobomi baselwandle kunye nezinto eziphilayo. Inkqubo ye- Izilwanyana ze-Ordovician kuye kwancipha ngokuqatha kwindalo eyahlukeneyo ekupheleni kwexesha ngenxa yesiganeko sokuphela.
Kule nqaku siza kukuxelela yonke into ofuna ukuyifumana malunga nezilwanyana ze-Ordovician kunye nokubaluleka kwayo.
Iimpawu zexesha le-Ordovician
Ngaphambi kokwazi izilwanyana ezazilawula izilwanyana ze-Ordovician, siza kwazi ukuba zeziphi iimpawu ngokubanzi zeli xesha. Ihlale iminyaka emalunga nezigidi ezingama-21 Umahluko obalulekileyo wemozulu phakathi kwesiqalo nesiphelo. Ekuqaleni kwexesha kwakubakho amaqondo obushushu aphezulu, kodwa njengoko ixesha lihamba kunye noluhlu lotshintsho lwendalo, iqondo lobushushu lehla kakhulu. Kwakunethuba lexesha lomkhenkce.
Olunye lweempawu ekumiswe kuzo ixesha le-Ordovician yile umnyhadala wokucinywa osuse i-85% yeentlobo zezinto eziphilayo, ingakumbi izinto eziphila elwandle. Ngokumalunga nokwakheka komhlaba kwexesha le-Ordovician, sifumanisa ukuba iplanethi yahlulwe yazii-supercontinents ezi-4: IGondwana (enkulu kunazo zonke), eSiberia, eLaurentia naseBaltic. Amathambo afunyenwe ematyeni ngeli xesha abonisa amatye amakhulu.
Ngokubhekisele kwimozulu, siyabona ukuba yayifudumele kwaye ishushu ekuqaleni. Amanye amaqondo obushushu afikelela kumaxabiso ama-60 degrees celcius. Nangona kunjalo, ekupheleni kweli xesha amaqondo obushushu ancipha ngendlela yokuba kubekho ukubakho komkhenkce obalulekileyo. Olu glaciation luchaphazele ikakhulu ilizwekazi laseGondwana. Ngelo xesha, eli lizwekazi lalisezantsi kweplanethi. Oonobangela be-glaciation abasaziwa, kodwa uninzi luthetha ngokuhla kwe-carbon dioxide. Izifundo zisenziwa ukufumana unobangela.
Ubomi be-Ordovician
Ngexesha Ordovician kwabakho iyantlukwano enkulu yobomi. Ingakumbi le ihlala elwandle yaphuhliswa. Siza kwenza uhlolisiso olufutshane kwizityalo ze-Ordovician. Ukuthathela ingqalelo ukuba phantse bonke ubomi baphuhliswa kwindawo yokuhlala elwandle, kubalulekile ukuba uqaphele ukuba Kwakukho abameli abavela kubukumkani basePlantae ikakhulu kwaye abanye bevela kubukumkani beFungi.
Ubulembu obuluhlaza buye banda kakhulu elwandle kwaye ezinye iintlobo zomngundo bezikhona ezizalisekisa umsebenzi njengakuyo nayiphi na i-ikhosistim: ukubola nokubola kwezinto eziphilayo ezifileyo. Kwakungekho naziphi na i-ecosystems kunye nezityalo, nangona ezinye ezincinci zaqala ukwenza ilizwekazi. Ezi zizityalo zokuqala ezisisiseko ezazingengomthambo. Ayikhange ibe nayo inkqubo ye-xylem kunye ne-phloem. Ngenxa yoku, kuye kwafuneka bahlale kufutshane namanzi ukwenza obu vimba bufumaneke.
Izilwanyana ze-Ordovician
Siza ukuchaza ukuba yintoni izilwanyana Ordovician kunye neempawu zayo eziphambili. Kufuneka kugxininiswe ukuba izilwanyana ze-Ordovician zazixhaphakile elwandle. Kwakukho iyantlukwano enkulu yezilwanyana ukusukela kwincinci nakwizinto zakudala ukuya kokuvela ngakumbi nangakumbi.
Siqala ngearthropods. Ingumda ocacileyo ngexesha le-Ordovician. Ngaphakathi kwabameli beli cala Singakhankanya ii-brachiopods, i-trilobites kunye noonomadudwane baselwandle. Ezi zazinemizekelo emininzi kunye neentlobo ezazisasazeka kulwandle lweli xesha. Kwakukho nezinye iintlobo zeekrustaceans.
Ngokubhekisele kwiimollusk, ziye zanda kakhulu ngendaleko. Kwezinye iilwandle cephalopods nautiloid, bivalves kunye gastropods. I-Gastropods yafudukela elunxwemeni lolwandle, kodwa kwafuneka ibuyele kuhlala kwindawo yokuhlala elwandle njengoko babephefumla i-gill. Le nto ayithethi ukuba banokusasazeka kwindawo yonke yomhlaba. Nangona iintlanzi zazikhona ukusukela ngeCambrian, iintlanzi ezinemihlathi ezinje ngecoccosteus zaqala ukubonakala ngexesha lezilwanyana zaseOrdovician.
Amakhorali awazange athandwe yedwa, kodwa aqala iqela. Ngeli xesha kwaveliswa izixhobo zokuqala zekorale. Ezinye iintlobo zeeponji zazisele zahlukile kwixesha langaphambili.
Ukuphela kobunzima bezilwanyana zaseOrdovician
Njengoko besesitshilo ngaphambili, enye yeempawu ezigqamileyo kweli xesha yenye yezinto eziphelayo ezacima i-85% yezilwanyana ezazikho ngelo xesha. Kwenzeka malunga ne-444 yezigidi zeminyaka eyadlulayo ngomda wamaxesha e-Ordovician naseSilurian. Iingcali zinokucinga kuphela malunga nokuba kutheni oku kupheliswa kwenzekile. Kwakungenxa yokutshintsha kweemeko zokusingqongileyo ngelo xesha. Umzekelo, inoxanduva lokuphela ukuhla kwearbon carbon dioxide. Oku kube negalelo ekunciphiseni irhasi kunye negalelo layo kwimpembelelo yendalo. Ngenxa yoko, kwabakho ukwehla kwamaqondo obushushu kwindalo esingqongileyo.
Oku kwehla kwamaqondo obushushu kubangele ubudala beqhwa obuchaphazela ikakhulu ilizwekazi laseGondwana. Kwi-glaciation kuphela ipesenti esezantsi yeentlobo ezisindileyo. Esinye isizathu sokuba izazinzulu zikholelwe ukuba kukho ukuphela kwezinto ngenxa yokuba ukuhla kwamaqondo olwandle. Le nkqubo yenzeke ngenxa yokuqikelelwa kobukhulu bomhlaba obabukho ngelo xesha. Oku kubangele ukuvalwa kolwandle lweLapetus ngokupheleleyo. Kuba uninzi lweentlobo ezikhoyo zazikho kwiindawo zaselwandle, oko kubangele okanye ukuphela kwazo uninzi lwazo.
I-Glaciation ngoyena nobangela uphambili wokutshatyalaliswa. Kukholelwa ukuba inxulumene nokwehla kwe-carbon dioxide esemoyeni. Abo basindileyo bakwazi ukuziqhelanisa nokwehla kwamaqondo obushushu kunye notshintsho kwimeko zokusingqongileyo. Isizathu sokugqibela sokuba oososayensi bacinge ukuba ukutshabalala kwenzekile kungenxa yokuqhuma okungathethekiyo. Le ithiyori yaphuhliswa kwiminyaka elishumi yokuqala yenkulungwane yama-XNUMX kwaye ithi unobangela kukuba uqhushumbo olukhulu lwenzeka emajukujukwini. Oku kubangele ukuba umhlaba ukhukuliswe yimitha ye-gamma ngenxa yokuqhuma.
Ndiyathemba ukuba olu lwazi ungafunda ngakumbi malunga nezilwanyana ze-Ordovician.