Ubomi baselwandle bunomdla ekufundeni nangona kusaziwa ngakumbi ngobomi basemhlabeni. Oku kwenza umdla wokwanda kolwandle kwaye bafuna ukufunda zonke iintlobo zezinto ezihlala elwandle naselwandle. Elinye lamaqela afunwa kakhulu kwizifundo zezi ezanyisayo zaselwandle. Ezi zilwanyana zavela kwizilwanyana zomhlaba ezabuyela elwandle malunga neminyaka engama-66 yezigidi eyadlulayo. Ukuze baphile kwimimandla yolwandle, kuye kwafuneka baphuhlise uthotho lokuhlengahlengiswa kwazo zonke iintlobo, njengoko siza kubona kweli nqaku.
Ngaba uyafuna ukwazi ngakumbi ngezilwanyana zasemanzini? Kule posi siza kukuxelela yonke into ngokweenkcukacha.
Zithini izilwanyana zaselwandle
Zili-120 iintlobo zezilwanyana zaselwandle ezibandakanyiweyo elwandle. Ezi zilwanyana kucingelwa ukuba ziye zakhula ngothotho lolungelelwaniso lomzimba ukuze ziphile kwezi meko. Kanye njengokuba iintlobo ezavela elwandle zinokukwazi ukuziqhelanisa nobomi basemhlabeni, ngokuchaseneyo kwavela kanjalo.
Kule meko, ingqikelelo ebandakanya izilwanyana zaselwandle ibanzi kwaye ayibandakanyi kuphela iintlobo zezinye zeerhafu. Sizahlulahlula zonke izilwanyana esizithatha njengezilwanyana zaselwandle:
- Iqela leecetaceans elenziwe ngeminenga, iipollpoises kunye namahlengethwa.
- Iipinipipe ezinje ngeewalrus, amatywina kunye neeotarium.
- Abantu baseSireni bathanda ii-dugong kunye nee-manatees.
- Iimbumba ezifana neembatyuma zolwandle kunye nekati yolwandle.
- Ewe kunjalo, sibandakanya ibhere emhlophe kunye nebhere emhlophe, ethathelwa ingqalelo njengezilwanyana zaselwandle, kuba uninzi lwezenzo zabo lwenziwa kubomi bolwandle. Bayakwazi nokuba semkhenkceni wolwandle kwaye bazisebenzise ukuzingela amaxhoba abo.
Phakathi kwezi zilwanyana siye sahlulahlula njengezilwanyana zaselwandle, sifumana ezinye ezichitha ubomi bazo bonke e Amanzi, ngelixa ezinye zikwenye indlela. Abo bachitha bonke ubomi babo kwindalo yolwandle zii-cetaceans kunye ne-sirenians. Ezi zizilwanyana eziye zaqhelana nobomi baselwandle kweli qela.
Yizilwanyana ezinkulu ezinomdla kakhulu kwezi media. Oku kubangele ukuxhaphaza kwezorhwebo ngokubhekisele kwezi zilwanyana. Ngenxa yemisebenzi yoluntu ebandakanya ezi zilwanyana zaselwandle, baninzi abantu abasesichengeni okanye abasengozini.
Bavela phi?
Ukuxhaphaza urhwebo lwezilwanyana zaselwandle ngabantu kungenxa yokufumana inyama, amanqatha, ioyile, ulusu, iimpondo zendlovu kwanemiboniso efana nale siyifumana kwimiboniso yezilwanyana nakwezinye zoo zezilwanyana zaselwandle.
Ezi ntlobo zinentshukumo kunye nenkxaso yamanye amaqela okusingqongileyo afuna ukukhusela abantu kunye nokunciphisa umonakalo owenziwe kubo. Ngenxa yokufun 'ukwazi kwezi zilwanyana kunye nothando abaluphalazayo, isidingo sabo sokwazi apho zivela khona sikhokelele kwizifundo ezininzi kuyo. Uninzi lwezigqibo zezi zifundo ziqinisekisa ukuba ezona zinyanya zakudala zezi zilwanyana zanyisayo Zifumaneka kuLwandle lwakudala lwaseTethys kwiminyaka engama-70 ezigidi eyadlulayo.
Ezi zinyanya ziye zafunyanwa zezona zivelise izinyanya zezilwanyana zaselwandle esizifumanayo namhlanje. Ngokucacileyo, hayi ngeempawu ezifanayo okoko izilwanyana ziguquka ngokuhamba kwexesha. Kuxhomekeka kwimeko yezendalo abakuyo, bayakwazi ukukhuthaza ukukhula kwamalungu athile avumela ukuba baphile bhetele kwiindawo ezahlukeneyo.
Nangona iinkqubo zokuzivelela kwezinto ezibangele ukuba ezi zilwanyana zihlale ngcono kwezi meko zingaqondwa kakuhle, kuyaziwa oko abayiyo iqela le-monophyletic. Oku kuthetha ukuba amaqela ahlukeneyo avela kwizinyanya ezahlukeneyo zasemhlabeni. Le nyani iyaziwa kwizifundo zeepatheni zokwakheka kweefosili kunye nokuthelekisa ukufana kweemolekyuli.
I-cetaceans kucingelwa ukuba zaziziihagu neenkomo ezinxulumene kude lee neemvubu ezinokuyivelisa. Amaqela amkela iimpawu ezifanayo zomzimba, ngenxa yesidingo sokuziqhelanisa nobomi baselwandle. Oku kwaziwa njengokuhlangana kwendaleko.
Ukulungiswa kwimeko-bume yasemanzini
Njengoko besitshilo ekuqaleni kwenqaku, ukuze sihlale kwindawo yolwandle, kuye kwafuneka ukuba kwenziwe uhlengahlengiso olwahlukeneyo kunye nokusebenza. Olu hlengahlengiso kufuneka lubavumele ukuba baphile kwimekobume yaselwandle. Ukuqonda olu hlengahlengiso, kuyafuneka ukuba wazi ukuba le meko-bume inezinto ezibonakalayo ezahluke kakhulu kuleyo yomhlaba. Ke ngoko, kubalulekile ukuba isilwanyana kufuneka siziqhelanise naso kwaye sazi ngakumbi ukuba sivela kubomi basemhlabeni.
Kutheni izilwanyana ezithile ziqhele ukuhlala elwandle kunzima kakhulu. Nangona kunjalo, bekukho izizathu zokuba ezinye izidalwa ezanyisayo zomhlaba ziphelise ubomi kwindalo yolwandle.
Olunye uhlengahlengiso lulungiselelwe ukuba lukwazi ukumelana nokuxinana kwamanzi okuphindwe kathathu kunoko kunomoya. I-viscosis yenye yezinto apho sifumana khona i-viscosity ephindwe kaninzi nakumaqondo obushushu afanayo. Ezi zinto zinempembelelo enkulu kumlo wokungqubana. Enye into ebalulekileyo ekufuneka uyiqwalasele luxinzelelo. Amanzi anengcinezelo enkulu emzimbeni ebangela ukuba ucinezeleke. Kwiimitha ezili-10 zobunzulu uxinzelelo luphezulu kakhulu.
Ukuqhutywa kwe-Thermal yinto ebalulekileyo ekufuneka uyiqwalasele. Ukugqithiselwa kobushushu kunye namandla okukhanya kuyancipha njengoko ubunzulu bonyuka.
Lonke olu tshintsho kwimeko-bume yobomi kuye kwafuneka lunyanzelise uhlengahlengiso oluhlukeneyo ukuze luphile kuzo. Olu hlengahlengiso lwalukhula ngokuhamba kweminyaka kwaye bathathe malunga nezigidi ezingama-60 zeminyaka ukugqibezela. Kude kube namhlanje, banokulungiswa ngakumbi ngakumbi.
Ndiyathemba ukuba ngolu lwazi unokwazi okungakumbi malunga nezilwanyana zaselwandle, imvelaphi yazo kunye nendlela yazo yokuphila.