Inkathi yePaleozoic yayinezikhathi ezingaba yisithupha kanti esinye sazo yi- Isikhathi se-Ordovician. Ngenye yezikhathi ezitholakala ngemuva nje kwe- Isikhathi seCambrian nangaphambili Isikhathi se-Silurian. Kubonakala ikakhulu ngokuba namazinga aphakeme olwandle abangele ukwanda kwempilo yasolwandle kanye nemvelo. I- Izilwane Ordovician ibe nokuncipha okukhulu kwezinhlobonhlobo zezinto eziphilayo ekupheleni kwesikhathi ngenxa yomcimbi wokuqothulwa.
Kulesi sihloko sizokutshela konke odinga ukukwazi mayelana nezilwane zakwa-Ordovician nokubaluleka kwazo.
Izici zesikhathi se-Ordovician
Ngaphambi kokwazi izilwane ezazibusa izilwane ze-Ordovician, sizokwazi ukuthi yiziphi izici ezijwayelekile zale nkathi yesikhathi ezazikhona. Ihlale cishe iminyaka eyizigidi ezingama-21 ngokuhlukahluka okubalulekile kwesimo sezulu phakathi kwesiqalo nesiphetho. Ekuqaleni kwenkathi kwakukhona amazinga okushisa aphakeme kakhulu, kepha njengoba isikhathi sihamba futhi ngochungechunge lokuguqulwa kwemvelo, izinga lokushisa lehla kakhulu. Kwakunenkathi yobudala beqhwa.
Esinye sezici inkathi ye-Ordovician evelele ngaso umcimbi wokuqothula osule ama-85% ezinhlobo zezinto eziphilayo, ikakhulukazi imvelo yasolwandle. Ngokuphathelene nokwakheka komhlaba kwesikhathi se-Ordovician, sithola ukuthi iplanethi yahlukaniswa yaba ngama-supercontinents amane: IGondwana (enkulu kunazo zonke), eSiberia, eLaurentia naseBaltica. Izinsalela ezitholwe emadwaleni ezivela kule nkathi zikhona ikakhulukazi amadwala asezintabeni.
Ngokuqondene nesimo sezulu siyabona ukuthi bekufudumele futhi kushisa ekuqaleni. Amanye amazinga okushisa afinyelela amanani we-60 degrees Celsius. Kodwa-ke, ekupheleni kwalesi sikhathi amazinga okushisa ancipha ngendlela yokuthi kwaba nokuqhwa okubalulekile. Le glaciation ithinte kakhulu izwekazi laseGondwana. Ngaleso sikhathi, leli zwekazi laliseningizimu yeplanethi. Izimbangela ze-glaciation azikaziwa, kepha eziningi zikhuluma ngokuncipha kokugxila kwe-carbon dioxide. Kusenziwa ucwaningo ukuthola imbangela.
Impilo ye-Ordovician
Ngesikhathi se-Ordovician kwakukhona ukwehluka okukhulu kwempilo. Ikakhulukazi leyo ehlala olwandle yasungulwa. Sizobuyekeza kafushane ngezimbali zakwa-Ordovician. Ngokubheka ukuthi cishe yonke impilo yathuthuka endaweni yasolwandle, kubalulekile ukuqaphela lokho kwakukhona abameleli abavela embusweni wePlantae ikakhulukazi abanye abavela embusweni weFungi.
I-algae eluhlaza yanda olwandle kanti ezinye izinhlobo zesikhunta zazikhona ezagcwalisa umsebenzi njenganoma iyiphi i-ecosystem: ukubola nokuhlakazeka kwezinto ezifile. Kwakungekho neze imvelo yasemhlabeni enezitshalo, yize ezinye ezincane zaqala ukolula izwe. Lezi yizitshalo zokuqala eziyisisekelo ezazingeyona imithambo yegazi. Kwakungekho ngisho nohlelo lwe-xylem ne-phloem. Ngenxa yalokhu, bekufanele bahlale eduze kakhulu kwamanzi ukuze bathole lo mthombo.
Izilwane Ordovician
Manje sizochaza izilwane ze-Ordovician nezici zayo eziyinhloko. Kufanele kugcizelelwe ukuthi izilwane zase-Ordovician zaziningi ngempela olwandle. Kwakukhona ukuhlukahluka okukhulu kwezilwane, kusukela kwezincane kunazo zonke nezindala kakhulu kuye kwezithuthuke kakhulu neziyinkimbinkimbi.
Siqala ngama-arthropods. Kungumkhawulo ogcwele ngokwanele ngesikhathi se-Ordovician. Ngaphakathi kwabamele lo mkhawulo singabala ama-brachiopods, ama-trilobites kanye nofezela basolwandle. Lezi zazinenqwaba yezinhlobo nezinhlobo ezazisakazeka olwandle lwalesi sikhathi. Kwakukhona nezinhlobo ezithile zama-crustaceans.
Ngokuqondene nama-mollusk, abhekana nokwanda okukhulu kokuziphendukela kwemvelo. Kwezinye izilwandle kwakukhona ama-nautiloid cephalopod, ama-bivalves nama-gastropods. Ama-gastropods athuthele ogwini lolwandle, kodwa kwadingeka abuyele ayohlala endaweni yasolwandle. njengoba babephefumula i-gill. Leli qiniso belingasho ukuthi bangahlakazeka kuyo yonke indawo yasemhlabeni. Yize izinhlanzi zazikhona kusukela eCambrian, izinhlanzi ezinemihlathi ezinjenge-coccosteus zaqala ukuvela ngesikhathi sezilwane zase-Ordovician.
Amakhorali awazange aziswe wedwa, kepha aqala ukuqoqwa. Ngalesi sikhathi, kukhiqizwa izixhobo zamakhorali zokuqala ezaziwayo. Ezinye izinhlobo zezipanji bezivele sezihlukahluka esikhathini esedlule.
Ukuqothulwa okukhulu kwezilwane zakwa-Ordovician
Njengoba sike sasho ngaphambili, esinye sezici ezigqamayo kulesi sikhathi singesinye sokuqothulwa kwezilwane okwaqothula amaphesenti angama-85 ezilwane ezazikhona ngaleso sikhathi. Kwenzeka cishe eminyakeni eyizigidi ezingama-444 edlule emngceleni wenkathi ye-Ordovician neSilurian. Ochwepheshe bangaqagela kuphela ukuthi kungani lokhu kushabalala kwenzeka. Lokhu mhlawumbe kwakungenxa yezinguquko ezimweni zemvelo ezazikhona ngaleso sikhathi. Isibonelo, ukushabalala kunesibopho sakho ukwehla kwe-carbon dioxide esemkhathini. Lokhu kube nomthelela ekwehleni kwegesi kanye negalelo layo kumphumela wokubamba ukushisa. Ngenxa yalokho, kube nokwehla kwezinga lokushisa kwemvelo emhlabeni jikelele.
Lokhu kwehla kwamazinga okushisa kwabangela isikhathi seqhwa esithinta kakhulu iGondwana yezwekazi elikhulu. E-glaciation kwasinda kuphela amaphesenti wezinto eziphilayo. Esinye isizathu esenza ososayensi bakholelwe ukuthi kwaba nokuqothulwa okukhulu kungenxa yokuthi ukwehla kwamazinga olwandle. Le nqubo yenzeka ngenxa yokusondela kwenqwaba yomhlaba eyayikhona ngaleso sikhathi. Lokhu kudale ukuthi kuvalwe ulwandle lweLapetus lonke. Njengoba iningi lezinhlobo ezikhona lalihlala ezindaweni zasolwandle, kubangele noma ukuqothulwa kweziningi zazo.
I-Glaciation iyimbangela eyinhloko yokuqothulwa kwalokhu. Kukholakala ukuthi kwakuhlobene nokuncipha kwe-carbon dioxide emkhathini. Labo abasindile bakwazi ukuzivumelanisa nokwehla kwezinga lokushisa nokushintsha kwezimo zemvelo. Isizathu sokugcina ososayensi bacabange ukuthi ukushabalala kwenzeke kwakuwukuqhuma kwe-supernova. Lo mbono wasungulwa eshumini lokuqala leminyaka lekhulu lama-21 futhi uthi imbangela kwakuwukuqhuma kwe-supernova emkhathini. Lokhu kuholele ekutheni uMhlaba ugcwale imisebe ye-gamma evela ekuqhumeni.
Ngiyethemba ukuthi ngalolu lwazi ungafunda kabanzi ngezilwane ze-Ordovician.