La Ixesha le-Oligocene yaba yeyesithathu neyokugqibela yamaxesha eyakha ixesha le Paleogene ICenozoic. Lixesha lexesha apho iplanethi yafumana okanye yabona utshintsho kwinqanaba lezinto eziphilayo kunye nokwakheka komhlaba. Inkqubo ye- Izilwanyana ze-Oligocene Ikwazile ukuchuma ngenxa yenguqu esisiseko kwimozulu eyadala iimeko ezifanelekileyo zokukhula kwezilwanyana nezityalo.
Kweli nqaku siza kukuxelela ngazo zonke iimpawu kunye nokuvela kwezilwanyana zaseOligocene.
Ixesha le-Oligocene
Eli xesha laqala malunga malunga nezigidi ezingama-34 zeminyaka kwaye yaphela malunga neminyaka engama-23 yezigidi eyadlulayo. Ngalo lonke eli xesha iplanethi yenze utshintsho olubonakalayo. Imozulu idlale indima ebalulekileyo kuphuhliso lwezityalo nezilwanyana. Olu tshintsho kwiplanethi lubangele ukuba izilwanyana kufuneka zisasazeke kwakhona kwiplanethi.
I-Oligocene ibilixesha elinike umdla kwiingcali kufundo lwexesha le-geological kuba banikezele ixesha kunye nomzamo owaneleyo wokucacisa ezona zinto zifihlakeleyo. Ixesha le-Oligocene limalunga neminyaka eli-11 yezigidi kwaye, ngeli xesha, ukuhamba kwamacwecwe etektoni kuyaqhubeka, kufikelela kwizikhundla ezifanayo nezo banazo namhlanje.
Izilwanyana ze-Oligocene zidume ngokwaziwa njengobudala bezilwanyana ezanyisayo. Kwaye lelokuba iqela lezilwanyana ezanyisayo lelona laye lafumana olwahluka-hlukeneyo olukhulu nolwahlukeneyo ngeli xesha. Enkosi kuphuhliso kunye nokwandiswa kwezilwanyana, iziqendu ezaziwayo ezifana neempuku kunye neecanids zinokwenziwa. Eyona nto igqame kakhulu kwijoloji yeli xesha yiLaramide orogeny kunye neAlpine orogeny.
Ngokubhekisele kwimozulu, iimeko ezichaze eli xesha zazimbi kakhulu. Lwaphawulwa ngamaqondo obushushu asezantsi kakhulu apho iipali zahlala zigutyungelwe ngumkhenkce. Ezinye izinto eziphilayo zaguqulwa ngokuhla kweqondo lobushushu behlabathi. Makhe sihlalutye ubomi ngcono.
Flora
Iintyatyambo zeOligocene zibonakaliswa ikakhulu ngamahlathi e-coniferous ahamba phambili kunye namahlathi aqaqambayo. La mahlathi alungiselelwe ukuba akwazi ukusinda kumaqondo obushushu asezantsi. I-Angiosperms yaqala ukusasazeka kwindawo enkulu yokuhlala, ukufumana isizinda esikhulu.
Ngenxa yemozulu ebandayo, ukwehla kwamahlathi ashinyeneyo kwaqwalaselwa, athatyathelw 'indawo zizityalo ezinamagqabi kunye nengca. Iindidi ezahlukeneyo zezityalo kwafuneka zijongane nokwenziwa kokutya kwamadlelo ezilwanyana ezizondlayo. Makhe sihlalutye ukuba zeziphi na ezi zilwanyana.
Izilwanyana ze-Oligocene
Izilwanyana zase-Oligocene zibonakaliswa ngokuba namaqela amaninzi ezilwanyana akwazileyo ukwahluka kwaye aphumelele nangona imeko yezulu ifunyenwe. Kula maqela ezilwanyana ezohlukeneyo sifumana iintaka, izilwanyana ezirhubuluzayo kunye nezilwanyana ezanyisayo. Ezinye izazinzulu zibiza izilwanyana zaseOligocene ubudala bezilwanyana ezanyisayo. Imalunga nexesha leCenozoic ukuba yintoni enye enokwanda ngokokuncancisa.
Inani elikhulu leentlobo zezilwanyana ezanyisayo zavela, phakathi kwazo sineempuku, ii-canids, ii-primates kunye neecetaceans. Siza kuhlalutya nganye nganye.
Iimpuku
Kulandelelwano lweempuku sifumana iqela elininzi lezilwanyana ezanyisayo ngexesha lezilwanyana zeOligocene. Uphawu lwayo olwalunceda ukwahlula kwabanye yayingamazinyo abukhali kakhulu asebenzisa izinto ezininzi. Enye yazo kukuluma amarhamncwa okanye ukutyumza iinkuni. Olona sapho lwaziwayo lweempuku yayingu-Eomyidae. Bayefana noonomatse namhlanje kodwa benomzimba omncinci kunye nemikhwa emibi.
Amatyala
Ziliqela lezilwanyana ezanyisayo eziphawuleka ngokuba neminwe emihlanu emilenzeni. Esinye sezibonelelo eziphambili zala marhamncwa ngaphezulu kwezinye izilwanyana ezincancisayo ubhontsi ophikisayo. Ukongeza, baneenyawo zokutyala ezivumela ukuba yonke inyawo ixhaswe ukuhamba. Ipateni yayo yamazinyo yenziwe gabalala kwaye ayikhethi kakhulu. Ama-primates anokujongwa rhoqo ngeli xesha yayiyi-lemur kunye ne-tarsier.
Itarsier ngumzala onobukhulu obuncinane obumalunga neesentimitha ezili-10. Ezona mpawu zabo ziphambili kukuba banamehlo amakhulu abavumela ukuba bahlengahlengise umbono wabo ebumnyameni. Batya ngokupheleleyo kwinyoka kwaye bachitha elona xesha labo limisiwe kumasebe emithi.
Ngakolunye uhlangothi, i-lemur sisilwanyana esincinci esingahluka ngokobukhulu ngokuxhomekeke kwii-subspecies. Olunye lweempawu ezibonakalayo ngumsila walo omde. Lo msila uhlala umde kunomzimba opheleleyo. Amehlo abo makhulu kwaye ivumela ukuba babone ubumnyama. Abayihluli kakuhle imibala nangona bekwazi ukwahlula iimilo.
Izilwanyana ze-Oligocene: ii-canids
Ngaphakathi kwe-canids bangabakwiqela leengcuka nezinja. Olona phawu luphambili kukuba nomzimba ophakathi kunye nokuhamba kuxhaswe kwiingcebiso zeminwe. Kukutya okutyayo kwaye uninzi lwazo ngamarhamncwa. Babonakala kwi-Eocene kwaye kamva bahluka.
Abantu baseCetaceans
Iqela lezilwanyana ezanyisayo ezikwaziyo ukuziqhelanisa nobomi baselwandle. Ezona mpawu zayo ziphambili zihlengahlengiswe ngaphambili ukuze zikwazi ukuba ngamaphiko. Amaphiko abo angasemva anyamalale ngokuhamba kwexesha. Ukuphefumla kwabo yipulmonary, ke kufuneka baphakame rhoqo ukuya kumphezulu ukuze bathathe umoya.
Ngexesha lezilwanyana ze-Oligocene Esona silwanyana sikhulu sasemhlabeni siphuhlileyo. Yaziwa ngokuba yiParaceratherium. Inemilinganiselo yokuqikelela ye phantse i-8 yeemitha ukuphakama kunye ne-7 yeemitha ubude. Babezizilwanyana ezirhabaxa ezinemvakalelo ephucukileyo yokuphunga. Kwakungathetheki kwaphela, kodwa babephila bodwa. Kuyabonakala ukuba babesilwa bodwa, bexabana iintloko kwaye bezikhuselwe ngamathambo okakayi ngakumbi kunesiqhelo.
Ndiyathemba ukuba olu lwazi ungafunda ngakumbi malunga nezilwanyana zase-Oligocene.