Esikhathini se-Paleozoic sithola izikhathi eziningana. Owesithathu wabo yi Isikhathi se-Silurian. Itholakala phakathi kwe- Isikhathi se-Ordovician futhi i Isikhathi se-Devonia. Esinye sezici zayo eziyinhloko ukusebenza okukhulu kwe-geological okwakhiwa izintaba ezinkulu. Mayelana ne- Izilwane zaseSilurian Sithola nokuvela okukhulu kwezinhlobo eziningi ezingeni lezinto eziphilayo. Lesi sikhathi sesikhathi sabuswa ngenani elikhulu lezinguquko kuzo zonke izilwane.
Ngakho-ke, sizonikezela le ndatshana ukukutshela zonke izici nokuvela kwezilwane zaseSilurian.
Isikhathi se-Silurian
Isikhathi salesi sikhathi sasiyiminyaka engaba yizigidi ezingama-25. Kwaqala cishe eminyakeni eyizigidi ezingama-444 edlule futhi kwaphela cishe eminyakeni eyizigidi ezingama-419 edlule. Kwakuyisikhathi esihle kakhulu kusukela ekubukeni kwe-geological. Ngaso sonke lesi sikhathi, ukwakheka kwezinhlelo zezintaba esizazi namuhla njengezintaba zase-Appalachian zaseNyakatho Melika kwenzeka.
Ngalesi sikhathi ukwehluka okukhulu kwempilo. Izitshalo zokuqala zemithambo zaqala ukuvela futhi izilwane zathola ukuvela okukhulu. Amakhorali nama-arthropods aphakathi kwezilwane ezavela kakhulu. Kwakukhona nenqubo yokuqothulwa okubhekwa njengezinga elincane. Le micimbi ithinte kakhulu izinto eziphilayo ezindaweni zasolwandle. Ngokwesibonelo, uhhafu wezinhlobo ze-trilobite wanyamalala ngenkathi yeSilurian.
Ngokuya ngesimo sezulu, iplanethi yazinza kancane ngokuya ngamazinga okushisa. Isimo sezulu saseSilurian sasifudumele kakhulu. Ngalezi zikhathi izinguzunga zeqhwa ezazakhe ngesikhathi sangaphambilini zazitholakala kakhulu ngaseningizimu yeplanethi. Kunobufakazi bemivubukulo obukhombisa ukuthi kube nesikhathi esikhulu sezivunguvungu ngalesi sikhathi. Ngemuva kwale micimbi yesimo sezulu, izinga lokushisa kwemvelo kwabonakala lincipha. Ifike eqophelweni lokuthi yaqala ukupholisa imvelo kancane kepha ingafinyelelanga eminyakeni yobudala beqhwa. Ekupheleni kwalesi sikhathi Isimo sezulu siqale ukuba nomswakama futhi sishise ngenqwaba yemvula.
Izimbali nezimila
Njengoba sishilo phambilini, konke okuthinta impilo, izimbali nezilwane, kube noshintsho olukhulu ngalesi sikhathi. Umcimbi omkhulu wokunweba wenzeka ngesikhathi sezilwane zaseSilurian lapho ezinye izinhlobo zingahlukahluka futhi esinye isigaba savela. Futhi ukuthi umcimbi wokuqothulwa usiza ukwakha ukuzivumelanisa okusha nezinhlobo eziphilayo.
Kuzimbali sithola inani elikhulu le-algae ezindaweni eziphilayo zasolwandle, ikakhulukazi ulwelwe oluhlaza. Lawa ma-algae ayenomsebenzi wokulawula ibhalansi yemvelo ngoba ayeyisisekelo sokwakhiwa komoya-mpilo kanye nesisekelo samaketanga e-trophic. Ngalesi sikhathi, kwenzeka ingqophamlando ekukhuleni kwezitshalo. Futhi yilokho izitshalo zokuqala zemithambo zaqala ukuvela. Lezi zitshalo yilezo ezinemikhumbi yokuqhuba eyaziwa njenge-xylem ne-phloem.
Ekuqaleni kwalesi sikhathi, ukwakheka kwezwe kwakukude nombuso esiwubona namuhla. Iningi lokwehlukahlukana kwakusezindaweni zasolwandle. Izitshalo zokuqala ezavela ezindaweni eziphila emhlabeni kwakudingeka bahlale eduze kwezidumbu zamanzi. Ngale ndlela babengathola ukutholakala okukhulu kwamanzi nezakhamzimba.
Izilwane zaseSilurian
Ekupheleni kwesikhathi se-Ordovician kube nenqubo yokuqothulwa okukhulu okuthinte inani elikhulu lezilwane ezikhona. Njengoba sishilo ngaphambili, inqubo yokuqothulwa kwesintu isiza izinhlobo eziphilayo ukuba zikwazi ukuzivumelanisa nezimo ezintsha ukuze ziphile endaweni entsha. Phakathi kwezinhlobo ezitholakele hlukanisa futhi uvumelane nalezi zindawo ezintsha esizithola kuma-arthropods. Ama-arthropods kwakuyizilwane ezazilawula izilwane zaseSilurian.
Ngenye yamaqembu abhekana nokuziphendukela kwemvelo okukhulu. Cishe kutholakale izinsalela ezingama-425 ezimele abantu bakule phylum. Ama-Trilobites anciphise ububanzi bawo nobuningi bawo ngenxa yesikhathi sokuphela. Ngalesi sikhathi Ama-myriapods nama-chelicerates aqale ukuvela okokuqala. Lezi zilwane zaqala ukusabalala kuzo zonke izindawo zomhlaba.
Ngakolunye uhlangothi, ama-mollusk nawo ayenokubuyiswa okuthile. Phakathi kwama-mollusk ayekhona ngaleso sikhathi sithola izinhlobo zama-bivalve nama-gastropods. Lezi zilwane zazihlala olwandle futhi zivumelane nale ndawo. Sithola nama-echinoderms njengezilwane ezikwazile ukuzivumelanisa nesikhathi sokuqothulwa. Ngaphakathi kwama-echinoderms sithola ama-crinoids agcina enciphisa inani labantu bawo. Lawa ma-crinoids athathwa njengama-echinoderms okuqala, ngakho-ke, amadala kunawo wonke emhlabeni.
Iqembu lezinhlanzi lingabona ukwehlukahlukana okuthile. Ngesikhathi se-Ordovician ama-ostracoderms avele ikakhulukazi ngokungabi nawo umhlathi. Lezi zilwane zithathwa njengezilwane ezinomgogodla ezindala kunazo zonke ezinamarekhodi ezinsalela. Kodwa-ke, ngesikhathi seSilurian ezinye izinhlobo zezinhlanzi zaqala ukuvela. Phakathi kwezilwane zaseSilurian kwesinye isikhathi sithola umhlathi owaziwa ngokuthi ama-placoderms. Esinye sezici zayo ezihlukile ukuthi zinegobolondo ngaphambili komzimba wazo ukuzivikela ezilwaneni ezizingelayo.
Ezinye izinhlobo zezinhlanzi ezavela ngesikhathi sezilwane zaseSilurian ngama-acanthods. Zaziwa njengama-spiny shark futhi ziyizinto eziphilayo ezifana ne-ostracoderms, izinhlanzi ezihlwabusayo. Kunokungabaza okuthile phakathi kososayensi mayelana nokuvela kwezinhlanzi ezi-cartilaginous. Abanye bathi bavele ngesikhathi sezilwane zaseSilurian, kanti abanye bathi bavela esikhathini esizayo.
Izilwane zaseSilurian: izixhobo zamakhorali
Izixhobo zamakhorali zazibaluleke kakhulu ezilwaneni zaseSilurian. Kuyaziwa ukuthi izixhobo zamakhorali zokuqala zavela esikhathini esedlule. Noma kunjalo, kwakungale nkathi yesikhathi lapho baqala khona ukwanda ngokwandayo. Izinhlobo ezihlotshaniswa nalezi zixhobo zamakhorali zikwazile ukwandisa indawo yazo yokusatshalaliswa nokuchichima. Lokhu kungenxa yokuthi lolu dwala lwamakhorali lwabanika konke abakudingayo ukuze baphile.
Ngenxa yokuguquguquka kwezinhlobo ezizungeze izixhobo zamakhorali, zazakhiwa izinhlobo ezahlukahlukene kakhulu. Phakathi kwezinto ezivame kakhulu ukugcinwa sinezipanji nezinye izinhlobo zama-crinoid eziseqenjini lama-echinoderms.
Ngiyethemba ukuthi ngalolu lwazi ungafunda kabanzi ngezilwane zaseSilurian.