El Isikhathi se-Devonia kwakha esinye sezigaba ezinhlanu ezazinenkathi yePaleozoic. Lesi sikhathi sinezinguquko eziningi kakhulu ezingeni le-geological kanye ne-biodiversity kuyo yonke iplanethi. Kwahlala cishe iminyaka eyizigidi ezingama-56 futhi amaqembu ahlukahlukene ezilwane angakhula, ikakhulukazi lawo asendaweni yasolwandle. Kwakukhona nezinguquko ezindaweni zokuhlala izilwane zomhlaba, lapho kwavela khona izitshalo ezinkulu nezilwane zokuqala zomhlaba. I- Izilwane zase-Devonia Kwakwaziwa ukuthi kungumgibeli wamahhashi kakhulu kude kakhulu. Yize lesi sikhathi saziwa ngokuba nesiqephu sokuqothulwa lapho okungaphezulu kwama-80% ezinhlobo zanyamalala.
Ngakho-ke, sizonikezela le ndatshana ukukutshela konke odinga ukukwazi mayelana nezilwane ze-Devonia.
Ukuthuthukiswa kwezilwane zase-Devoni
Le nkathi yayiphelele ukuthuthukisa impilo. Futhi ukuthi amazinga okushisa abemnandi ngalesi sikhathi futhi avumela ukuthuthukiswa okuhle kwezilwane nezitshalo. Zonke izilwandle ezikhona kulesi sikhathi zazinezinga eliphezulu lokuphila. Futhi ukuthi olwandle lezo zinhlobo zakudala kakhulu njengezipanji zingakhula. Izinhlobo zezipanji ezinothile zaqala ukuvela futhi ngokuchuma emadwaleni ama-coral, bakwazi ukwakha ukujwayela okuhlukile. Izipanji ezinesiliceous zinokumelana okukhulu nezimo zemvelo kanye nokuba khona kwezilwane ezidlayo.
Imifula yamakhorali kanye ne-alga benthic nayo yadlala indima enkulu ekuthuthukiseni i-ocean morphology.. Isixhobo esikhulu sasolulwa ngaleso sikhathi sisuka ebangeni eliyizinkulungwane zamakhilomitha esinqamula izwekazi lonke. Izilwane ze-Devonia zibe nolunye lwezinguquko ezinkulu kakhulu emvelweni yasemanzini njengoba kuvela izilwane zektonic. Eziningi zalezi zinhlobo zezilwane ezintsha zazizingela.
Lapho kunokuthuthuka okusha kohlobo noma lokuzivumelanisa nemvelo, ingcindezi itholakala kuloluchungechunge lwe-trophic. Lokho wukuthi, uma kunezilwane ezintsha ezizingela inyamazane yazo, ithuthukisa isimilo esisha ezinhlotsheni ezidinga ukubaleka ziphunyuke kulezi zimo zisaphila. Lokhu kuguqulela enkathini yokuziphendukela kwemvelo nokuzivumelanisa nezimo ezintsha ezakha ukwehluka kohlobo lwezilwane nezitshalo.
Ezindaweni eziphila emanzini siphinde siveze ukuthuthukiswa kokuhlukaniswa kwezinhlamvana okwenza ukuthi kuvele ama-ammonoid okuqala. Lawa ma-ammonoid avela ekuveleni kwama-nautiloid ngesikhathi sezilwane ezisezingeni eliphansi laseDevonia. Ama-nautiloid aqhubeka yize enokwehluka okuncane nobuningi.
Izilwane zasemanzini zase-Devonia
Ezindaweni ezihlala emanzini angenasawoti ama-bivalve aqala ukwanda futhi ahlasele. Ngaleso sikhathi ama-trilobite aqala ukwehla kancane kancane yize izinhlobo ezintsha zokuphila zazisavela. Kwakunama-trilobite amakhulu. Ngakolunye uhlangothi, sasinama-eurypterid arthropods, aqhubeka nokuba yiqembu elibaluleke kakhulu lezilwane ezidlayo.
Ngesikhathi salokhu kunwetshwa kwezilwane zasemanzini zase-Devoni zazilinga ekukhuleni kwezinhlanzi. Ikakhulukazi kwakungu-placoderms noshaka, kokubili ama-osteichthians kanye nama-sarcopterygians, okuvela kuwo ama-vertebrate omhlaba, njengama-actinopterygians. Leli qembu lokugcina yilona okwamanje eligcwele ulwandle. Kukhona ososayensi abazi ukuthi izilwane zase-Devoni zineminyaka yobudala bezinhlanzi. Lokhu kungenxa yokuthi kukhona izinsalela zalezi zinhlanzi ezahlukahlukene kakhulu futhi ezigcinwe kahle, iningi lazo lifakwa echibini lamanzi angenasawoti.
Ngalesi sikhathi ama-coelacanths asevele ethandana. Maphakathi nezilwane ze-Devoni ama-placoderms aqala ukudlula ama-ostracoderms. Lokhu okwenza i-Ichthyostega ne-Acanthostega kuqhamuke ohlwini lozalo lwe-sarcopterygian. Le mikhakha emibili ixhunyaniswe nokushintshwa kwenhlanzi iye kuma-tetrapods. Lokhu kuguquka okungokomlando kwenziwe ngesikhathi soguquko phakathi kwezilwane ze-Devonia kanye ne Isikhathi seCarboniferous.
Okunye ukungabaza okukhulu okukhona ngalezi zinhlanzi ukuthi kwakungamanzi ahlanzekile noma amanzi asolwandle. Lokhu kungabaza kuvela eqinisweni lokuthi izinhlanzi eziningi zamanzi angenasawoti zitholakale kumadiphozi amatshe amadala abomvu esihlabathi. Le ndawo eyomhlaba futhi yakhiwa ngokuvalwa kolwandle i-Iapetus. Lesi yisona sizathu esikhulu sokungabaza kanti lezi zinhlanzi bekungamanzi angenasawoti noma olwandle. Amarekhodi okuqala anikezwa ngalezi zinhlanzi atholakala ngezindlela zasolwandle, yize iningi lazo bayizinhlanzi zasemanzini ezingenasawoti. Ukusuka lapho, kwavela amaqembu ehlukene ezinhlanzi.
Ukwenziwa amakoloni komhlaba
Esinye isici esiyinhloko esenza izilwane zasendle zaseDevonia zigqame ukwenziwa komhlaba ngamakoloni. Ngesikhathi se- Isikhathi se-Silurian cishe ama-arthropods ahlasela izwe. Kodwa-ke, imininingwane yokuqala ivela ekwakhiweni kweLower Devonian Rhynie Chert yaseScotland. Lolu lwazi luphethe wonke umphakathi wezitshalo kanye ne-arthropods enikeze imininingwane enhle ngemvelo yakudala yezindawo zokuqala zomhlaba.
Kunezinhlobo eziningi zezitshalo ezisize i-arthropods, kufaka phakathi ofezela, izibungu nezinambuzane ezinamaphiko, ukuthuthukisa futhi kube nohlelo olufanele lwemvelo. Ama-arthropods asolwandle namanzi ahlanzekile kudingeke ukuthi iguquke ezinhlelweni zomhlaba ngenxa yokuthuthuka kokuphefumula komoya. Kodwa-ke, kunzima ukuthola ngemininingwane egciniwe yezinsalela ukuthi kukhona ukubala okulungile ngokwengeziwe ngomyalelo wokufika kwezibungu, ofezela kanye nabaziphilisa ngemvelo yomhlaba. Zonke lezi arthropods namuhla zinezizukulwane ezahlukahlukene ngokweqile futhi ziguqulelwa ezimweni ezahlukahlukene kakhulu zemvelo futhi ngenxa yokuthuthuka kwezitshalo zemithambo.
Ngaphambi kokuvela kwama-vertebrate, umhlaba wonke wakudala wawugcwele ama-arthropods. Kukhona impikiswano ethile eqhubeka nokusabalala emhlabeni wezesayensi futhi ibhekane nesikhathi lapho ama-vertebrate ephuma khona emanzini nezimbangela ezaziqhubezela ukuthi zenze njalo. Kumele kuvunywe ukuthi kunzima ukucabanga ukuthi isilwane esinemvelo yasolwandle sigcina sithuthukisa ukuzivumelanisa nendawo ebingakaze ihlale kuyo futhi engadingi ukuhlala kuyo.
Ngiyethemba ukuthi ngalolu lwazi ungafunda kabanzi ngezilwane ze-Devonia.