El Ixesha le-Devoni Kwenziwa esinye sesahlulo esinexesha lePaleozoic. Eli xesha lalinenani elikhulu lotshintsho kwinqanaba lomhlaba kunye neziphilayo kwihlabathi liphela. Iqhubeke iminyaka emalunga nezigidi ezingama-56 kwaye amaqela ahlukeneyo ezilwanyana anokukhula, ngakumbi lawo ahlala elwandle. Kwakukho notshintsho kwindawo yokuhlala yezilwanyana zomhlaba, apho izityalo ezikhulu kunye nezilwanyana zokuqala zomhlaba zavela khona. Inkqubo ye- Izilwanyana zedemon Yayisaziwa njengoyena mntu ukhwela ihashe kude kakhulu. Nangona eli xesha lidume ngokuba nesiqendu sokuphela apho ngaphezulu kwama-80% eentlobo zanyamalala.
Ke ngoko, siza kulinikela eli nqaku ukuba likuxelele yonke into ekufuneka uyazi malunga nezilwanyana zase-Devonia.
Uphuhliso lwezilwanyana eDevoniya
Eli xesha lalifezekile ukuphuhlisa ubomi. Kwaye kukuba amaqondo obushushu ayemnandi ngeli xesha kwaye avumela ukukhula okuhle kwezilwanyana nezityalo. Zonke iilwandle ezikhoyo ngeli xesha zazinomgangatho ophezulu wokuphila. Kwaye kulwandle kukho ezona ntlobo zidala zinjengeziponji. Iintlobo zesiponji ezi-siliceous zaqala ukubonakala kwaye ngokuchuma kwimithombo yolwandle bekwazile ukwenza uhlengahlengiso olwahlukileyo. Iiponji ezinesiliceous zinokuchasana ngakumbi neemeko zokusingqongileyo kunye nobukho bamarhamncwa.
Iingqaqa zekorale kunye ne-algae ye-benthic nazo zidlale indima ebalulekileyo kuphuhliso lwe-morphology yolwandle.. Uqaqa olukhulu lwandiselwa ngelo xesha ukusuka kumawakawaka eekhilomitha awanciphisa ilizwekazi liphela. Izilwanyana ze-Devonia zazinolona tshintsho lukhulu kwindalo yasemanzini njengoko kwavela izilwanyana zektonic. Uninzi lwezi ntlobo zintsha zezilwanyana zazingamarhamncwa.
Xa kukho uphuhliso olutsha lweentlobo okanye ulungelelwaniso lokusingqongileyo, uxinzelelo lwenziwa kwityathiki yetropiki. Oko kukuthi, ukuba kukho amarhamncwa amatsha azingela ixhoba lawo, ikhuthaza indlela entsha yokuziphatha kwindalo ekufuneka ibalekile kwaye ibaleke iphila kwezi meko. Oku kuguqulela kwixesha lokuzivelela kunye nokuziqhelanisa neemeko ezintsha ezenza ukwahlukahlukana kwemfuza yezilwanyana nezityalo.
Kwindawo ephila emanzini sibonisa ukukhula kweeyantlukwano zeemollusk ezibangela ii-ammonoids zokuqala zivele. Ezi ammonoids zivela kwindaleko yee nautiloid Ngexesha lezilwanyana ezisezantsi zeDevonia. I-nautiloids iqhubekile nangona iyantlukwano encinci kunye nentabalala.
Izilwanyana zasemanzini ze-Devonia
Kwiindawo ezihlala amanzi amatsha, ii-bivalves zaqala ukwanda kwaye zahlasela. Ngelo xesha ii-trilobites zaqala ukwehla kancinci kancinci nangona iindlela zokuphila zazisabonakala. Kwakukho ezinye i-trilobites ezinkulu. Ngakolunye uhlangothi, sine-eurypterid arthropods, eyaqhubeka nokuba liqela elibaluleke kakhulu lezilwanyana.
Ngexesha lokwandiswa kwezilwanyana zasemanzini ze-Devonia zazilinga ekukhuleni kweentlanzi. Ngokukodwa yayiyi-placoderms kunye nookrebe, bobabini i-osteichthians kunye ne-sarcopterygians, ezivela kuwo izilwanyana ezinomqolo, ezinje ngee-actinopterygians. Eli qela lokugqibela lelo lixhaphakileyo elwandle. Kukho izazinzulu ezazi izilwanyana zase-Devoni njengobudala beentlanzi. Kungenxa yokuba kukho iifosili ezahlukileyo nezigcinwe kakuhle zamathambo ezi ntlanzi, uninzi lwazo lukwindawo yokugcina amanzi echibi.
Ngeli xesha ii-coelacanths sele zinomhla. Embindini wezilwanyana ze-Devoni ii-placoderms zaqala ukoyisa ii-ostracoderms. Oku kwenza ukuba i-Ichthyostega kunye ne-Acanthostega zivele kumnombo we-sarcopterygian. Ezi zigaba zimbini zidityaniswe notshintsho lweentlanzi ukuya kwiietretrodod. Olu tshintsho lwembali lwenziwe ngexesha lotshintsho phakathi kwezilwanyana ze-Devonia kunye Ixesha leCarboniferous.
Olunye luthandabuzo olukhulu olukhoyo ngezi ntlanzi kukuba yayingamanzi amatsha okanye amanzi olwandle. Lo mathandabuzo uvela kwinto yokuba iintlanzi ezininzi zamanzi acocekileyo zifunyenwe kwiidipozithi zamatye esanti amadala abomvu. Lo mmandla usemhlabeni kwaye wenziwa ngokuvalwa kolwandle i-Iapetus. Esi sesona sizathu siphambili sokuthandabuza kwaye ezi ntlanzi yayingamanzi amatsha okanye amanzi olwandle. Iirekhodi zokuqala ezinikezelweyo kwezi ntlanzi zifunyenwe ngeendlela zaselwandle, nangona uninzi lwazo bazintlanzi zasemanzini ezingenanto. Ukusuka apho, amaqela ahlukeneyo eentlanzi avela.
Ukoloniyali womhlaba
Olunye uphawu oluphambili olwenza ukuba izidalwa zaseDevonia zigqame kukuthanjiswa komhlaba. Ngexesha le Ixesha leSilurian kusenokwenzeka ukuba iarthropods yahlasela umhlaba. Nangona kunjalo, idatha yokuqala ivela ekusekweni kwe-Lower Devonian Rhynie Chert yaseScotland. Olu lwazi luqulathe lonke uluntu lwezityalo kunye nezixhobo ezinikezela ngolwazi olukhulu malunga nendalo yokuqala yendawo zokuqala zomhlaba.
Zininzi iintlobo zezityalo ezincedise iarthropods, kubandakanya oonomadudwane, iimites, kunye nezinambuzane ezinamaphiko, ukuphuhlisa kunye nokuba nendawo efanelekileyo yokuhlala. Iarthropods yolwandle kunye namanzi amatsha kuye kwafuneka ukuba iguquke kwiinkqubo zasemhlabeni ngenxa yokuphuhliswa kokuphefumla komoya. Nangona kunjalo, kunzima ukufumanisa ngedatha yerekhodi yefosili ukuba kukho ubalo oluchanekileyo ngakumbi malunga nokufika kwezidalwa, oonomadudwane kunye neepentipedes kwinkqubo yendalo yomhlaba. Zonke ezi arthropods namhlanje zinenzala eyahlukileyo engaqhelekanga kwaye zilungelelaniswe neemeko zokusingqongileyo ezahlukileyo enkosi nangokuphuhliswa kwezityalo ezinemithambo.
Phambi kokuvela kwama-vertebrate, lonke ilizwe lantlandlolo laligcwele iarthropods. Kukho impikiswano ethile eqhubeka nokusasazeka kwihlabathi lezenzululwazi kwaye ijongana nomzuzu xa i-vertebrate yaphuma emanzini kunye nezizathu ezayityhalayo ukuba yenze njalo. Kuyavunywa ukuba kunzima ukucinga ukuba isilwanyana esinendawo yokuhlala izinto eziphila elwandle siphela sikhulisa ubume bendawo esingakhange sihlale kuyo kwaye singadingi kuphila.
Ndiyathemba ukuba ngolu lwazi ungafunda ngakumbi malunga nezilwanyana zase-Devonia.