Ngaba Imfundiso Yendaleko Iyinyaniso?
Ngaba Imfundiso Yendaleko Iyinyaniso?
“IMFUNDISO yendaleko iyinyaniso njengokuba kunjalo ngobushushu belanga,” watsho njalo uNjingalwazi Richard Dawkins, isazinzulu esaziwayo sendaleko. Phofu ke, uhlolisiso olwenziweyo naxa kuqwalaselwa izinto ngokungqalileyo, kungqina ukuba ilanga lishushu. Kodwa ngaba uhlolisiso noko kubonakalayo kunikela ubungqina obungenakukhanyelwa bemfundiso yendaleko?
Ngaphambi kokuba siphendule loo mbuzo, kukho into esifanele siyiqonde. Izazinzulu ezininzi ziye zaphawula ukuba emva kwexesha elide, inzala yezinto ezifanayo iyaguquka kancinane. UCharles Darwin wayibiza le nkqubo ngokuthi, “yinzala ephuculiweyo.” Oko kuguquka kuye kwaphawulwa ngokoqobo, kwabhalwa phantsi emva kokuba kwenziwe ulingelo kwaza ngobulumko kwasetyenziswa ngabalimi nabafuyi. * Ezi nguqulelo zinokugqalwa njengobungqina bokwenene. Noko ke, izazinzulu ziwubiza lo mahluko mncinane ngokuthi yindaleko encinane (microevolution). Kwanendlela ebizwa ngayo le nkqubo, ibonisa oko kuthethwa zizazinzulu ezininzi—ukuba ezi nguqulelo zincinane zibubungqina bokwenzeka kwento eyahlukileyo, ekungekho mntu wakha wayibona, eziyibiza ngokuba yindaleko enkulu (macroevolution).
UDarwin lo ke yena wazibona izinto ngenye indlela. Kwincwadi yakhe eyaziwayo ethi The Origin of Species uDarwin wathi: “Andiqondi ukuba zonke izinto eziphilayo zidalwe ngokuthe ngqo, kodwa zisuka kumnombo omnye wezinto eziphilayo ezimbalwa.” Emva kwexesha elide, lo kaDarwin wathi ezi “zinto ziphilayo zimbalwa” zamandulo, zaguquka ngokuthe ngcembe—zisenza “impucuko encinane gqitha”—nto leyo eyenze kwakho izigidi zezinto eziphilayo ezingafaniyo emhlabeni. Abo bakholelwa kwindaleko bafundisa ukuba ezi nguqulelo zincinane zibangele iinguqulelo ezinkulu ezibangele ukuba intlanzi iguquke ibe sisilwanyana esikwaziyo ukuphila emhlabeni nasemanzini neemfene ziguquke zibe ngabantu. Ezi nguqulelo kuthiwa zenzekile zibizwa ngokuba yindaleko enkulu. Kwabaninzi, le mfundiso yesibini ibonakala ibhadlile. Bayazibuza, ‘Ukuba kunokwenzeka iinguqulelo ezincinane kwizinto eziphilayo, kutheni indaleko ingenakubangela iinguqulelo ezinkulu emva kwexesha elide?’ *
Imfundiso yeenguqulelo ezinkulu isekelwe kwizinto ezintathu ezisisiseko:
1. ukuguquka kwemizila yemfuza kubangele kwakho izinto eziyimfuneko ukuze kuvele izidalwa ezitsha, *
2. ukuzikhethela kwemvelo kubangele ukuba kubekho izidalwa ezitsha, yaye
3. izinto ezaziphila mandulo zingqinelana nokuguquka okukhulu kwezityalo nezilwanyana.
Ngaba ubungqina bokuguquka okukhulu kwezinto bunamandla kangangokuba bufanele bugqalwe njengobuyinyaniso?
Ngaba Ukuguquka Kwemizila Yemfuza Kunokuvelisa Izidalwa Ezitsha?
Iinkcukacha ezininzi zesityalo okanye isilwanyana zixhomekeke kwimiyalelo efumaneka kwimizila yaso yemfuza, inkcazelo efumaneka kumbindi weseli nganye. * Abaphandi bafumanise ukuba ukuguquka kwemizila yemfuza kusenokuvelisa iinguqulelo kwizityalo eziveliswe zezinye nakwinzala yezilwanyana. Ngowe-1946, uHermann J. Muller, owafumana iBhaso likaNobel nowokuqala ukufumanisa ukuguquka kwemizila yemfuza, wathi: “Ukuguquka kwemizila yemfuza kwizilwanyana nakwizityalo akubangelwa nje kuphela ngabantu, kodwa ubukhulu becala, leyo yindlela indaleko eyenzeke ngayo, ngokuzikhethela kwemvelo.”
Imfundiso yokuguquka okukhulu kwezinto isekelwe kwibango lokuba ukuguquka kwemizila yemfuza kunokuvelisa kungekuphela nje izidalwa ezitsha kodwa kwakhona nohlobo olutsha lwezityalo nezilwanyana. Ngaba ikho indlela yokukuqinisekisa oku? Phawula oko kuveliswe luhlolisiso oluthabathe iminyaka enokuba li-100 yophando ngemizila yemfuza.
Ngasekupheleni kweminyaka yee-1930, izazinzulu zayamkela zichwayitile ingcamango yokuba, ukuba indalo inokukhetha ukuvelisa izityalo ezitsha ngokuguquka okuzenzekelayo kwemizila yemfuza, ngoko ke, umntu ufanele akwazi ukukwenza oku ngokuphumelela ngakumbi ngokuguqula imizila yemfuza. UWolf-Ekkehard Lönnig, isazinzulu seMax-Planck-Institute for Plant Breeding Research eJamani kudliwano-ndlebe noVukani! wathi: “Babexhelelw’ eXhukwane abafuyi nezazi ngendalo nezemizila yemfuza.” Yintoni le yayingaka? Lo kaLönnig, owayechithe iminyaka enokuba ngama-28 ephanda ngokuguquka kwemizila yemfuza kwizityalo, uthi: “Aba baphandi babecinga ukuba ngoku babeza kukwazi ukuguqula indlela eqhelekileyo yokuvelisa uhlobo olutsha lwezityalo nezilwanyana. Babecinga ukuba ngokuphembelela nokukhetha indlela abafuna iguquke ngayo imizila yemfuza, babenokuvelisa uhlobo olutsha nolubhetele lwezityalo nezilwanyana.” *
Izazinzulu zaseMerika, zaseAsia nezaseYurophu zaqalisa uphando olwaxhaswa ngezityhwentywe zemali, zisebenzisa iinkqubo ekuthiwa zaziza kuyikhawulezisa indaleko. Yintoni eyaveliswa lolu phando lunzulu olwathabatha iminyaka engaphezu kwengama-40? UPeter von Sengbusch nongumphandi uthi: “Phezu kwako nje ukusetyenziswa kweemali ezinamagama, liye lawa phantsi ilinge lokwandisa imveliso eyahlukahlukeneyo ngokuguqula imizila yemfuza.” Yena okaLönnig wathi: “Ngeminyaka yee-1980, amathemba namaphupha ezazinzulu aphelel’ emoyeni ehlabathini lonke. Amazwe aseNtshona atsho ancama xa ayezama ukuvelisa izityalo ezitsha ngokuguqula imizila yemfuza. Zonke izityalo ezaguqulwa imizila yemfuza zafa okanye zaba buthathaka kunezo zemvelo.” *
Sekunjalo, inkcazelo ngoku efunyenweyo kuphando lweminyaka enokuba li-100 yokuguqulwa kwemizila yemfuza kuzo zonke izinto nophando lweminyaka engama-70 yokuguqula imizila yemfuza kwizilwanyana luye lwazinceda izazinzulu zafikelela kwisigqibo ngenkqubo yokuveliswa kweendidi ezintsha zezinto eziphilayo ngokuguqulwa kwemizila yemfuza. Emva kokuhlolisisa le nkcazelo, uLönnig ugqiba ngelithi: “[Izityalo okanye izilwanyana] azinakuvelisa uhlobo olutsha lwemveliso okanye inzala ngokuguqulwa kwemizila yazo yemfuza. Esi sigqibo sivumelana nawo onke amalinge nophando lokuguqulwa kwemizila yemfuza olwenziwe kwinkulungwane yama-20 kunye nemithetho yemvelo. Ngoko ke, umthetho wokuguquka okufanayo uthetha ukuba imizila yemfuza inemiqathango engenakucimeka okanye nengenakutyeshelwa ngokuguqulwa kwemizila yemfuza.”
Makhe sicinge ngokuthethwa yile nkcazelo. Ukuba izazinzulu ezingoomakhwekhwetha azikwazi kuvelisa iindidi ezintsha zezinto eziphilayo ngokuguqula imizila yemfuza ngendlela ezifuna ngayo, kubonakala kungenakwenzeka ukuba oku kunokusuka nje kuzenzekele ngokuphumelelayo. Ukuba uphando lubonisa ukuba akunakuveliswa udidi olutsha lwento ephilayo ngokuguqulwa kwemizila yemfuza, kumele ukuba kuthiwa yenzeka njani indaleko enkulu?
Ngaba Indalo Iyazikhethela Ize Idale Into Entsha?
UDarwin wayekholelwa ukuba indalo ikhetha ukuvelisa izinto eziphila kuloo ndawo zikuyo, ngoxa izinto eziphila nzima kwindawo ethile zisifa. Oonondaleko bale mihla bafundisa ukuba njengokuba izinto eziphilayo zinwenwela kwezinye iindawo zize zibe kude kwezinye, indalo ikhetha ezo ukuguquka kwemizila yazo yemfuza kuzenze zakwazi ukuphila kwindawo entsha ezikuyo. Ngenxa yoko, izazi ngendaleko zithi, ezo zinto zikude nezinye ekugqibeleni zivelisa iintlobo ezintsha zezinto eziphilayo.
Njengokuba sibonile ngaphambilana, ubungqina bophando bubonisa ukuba izinto eziphilayo azikwazi ukuvelisa iindidi ezintsha. Sekunjalo, oonondaleko banabungqina buphi ukuxhasa ingcamango yokuba indalo ikhetha izinto eziye zakwazi ukuguqula imizila yazo yemfuza ukuze ivelise iindidi ezintsha zezinto eziphilayo? Incwadana enemifanekiso yowe-1999 yeNational Academy of Sciences (NAS) eMerika ithi: “Umzekelo obalaseleyo [wokudaleka kweendidi ezintsha] ngowoononkxwe abaziindidi ezili-13 abahlolwa ngokaDarwin kwiZiqithi iGalápagos, ngoku ababizwa ngokuba ngoononkxwe bakaDarwin (Darwin’s finches).”
Ngeminyaka yee-1970, iqela labaphandi elalikhokelwa nguPeter noRosemary Grant laqalisa ukuphonononga olu hlobo lweentaka laza lafumanisa ukuba emva konyaka wembalela, kusinde oononkxwe abanemilomo emikhulu abaninzi kunabo banemilomo emincinane. Ekubeni ubukhulu nokumila kwemilomo iyenye yezinto eziphambili ukwahlula ezi ndidi zili-13 zoononkxwe, kukho inkolelo yokuba oku kufunyenweyo kubalulekile. Le ncwadana inemifanekiso ihlabela mgama isithi: “AbakwaGrant baqikelela ukuba xa kunokubakho imbalela kube kanye kwiminyaka eli-10 kwezi ziqithi, kunokuvela uhlobo olutsha loononkxwe kuphela emva kweminyaka enokuba ngama-200.
Noko ke, le ncwadana inemifanekiso yeNAS ayizikhankanyi ezinye zeengongoma ezibalulekileyo kodwa ezibangel’ iintloni. Kwiminyaka eyalandela imbalela, baphinda banda kakhulu oononkxwe abanemilomo emincinane kunabo banemilomo emikhulu. Ngeso sizathu, uPeter Grant noLisle Gibbs osafundayo babhala kulindixesha wenzululwazi iNature ngowe-1987 besithi babone “ukuguquka kwindlela indaleko ekhetha ngayo.” Ngowe-1991, lo kaGrant wabhala esithi, “ezi ntaka ziyimveliso yokuzikhethela kwemvelo yaye ziyanda ziphinde zinciphe” nanini na kuguquka imozulu. Kwakhona abaphandi baphawula ukuba ezinye “iindidi” ezintsha zoononkxwe ziyazalelana zize zivelise amantshontsho aphila ixesha elide kunoonina. UPeter noRosemary Grant bafikelela kwisigqibo sokuba ukuba ezi ntaka ziqhubeka zizalelana, oku kunokuphelela ekubeni “iindidi” ezintsha ezimbini zibe ludidi olunye emva kweminyaka engama-200.
Ngowe-1966, isazinzulu sendaleko uGeorge Christopher Williams wathi: “Ndiva intw’ embi ukuba ingcamango yokuzikhethela kwemvelo yabakho njengenkcazelo yokuguquka kwendaleko. Ingathi le nkcazelo ichaza ukukwazi kwezinto eziphilayo ukuvumelana neemeko eziguquguqukayo.” UJeffrey Schwartz othethela indaleko wabhala esithi ngowe-1999, ukuba inkcazelo kaWilliams ichanile, ukukhetha kwemvelo kusenokuba kunceda iindidi ezahlukeneyo ukuba ziqhelane nokuguquka kweemeko, kodwa “akuvelisi nto intsha.”
Enyanisweni, oononkxwe bakaDarwin abaguquki babe ‘yinto entsha.’ Basengoononkxwe. Ukuzalelana kwabo kubangela amathandabuzo kwiindlela ezisetyenziswa ngabanye oonondaleko ukuchaza iindidi zezinto eziphilayo. Ukongezelela, babonisa nokuba nabona bantu baziingcungela kwinzululwazi banikela ingxelo engachananga ngophando lwabo.
Ngaba Amathambo Ezinto Zakudala Angqinelana Nokuguquka Okukhulu Kwendaleko?
Incwadana enemifanekiso yeNAS ekuthethwe ngayo ngaphambilana ishiya umfundi ecinga ukuba amathambo afunyenwe zizazinzulu angqinelana ngokupheleleyo nokuguquka okukhulu kwendaleko. Le ncwadana ithi: “Kufunyaniswe iindidi ezininzi zezinto eziphilayo phakathi kwentlanzi nezinto eziphila emanzini nasemhlabeni, izinto eziphila emhlabeni nasemanzini nezinto ezirhubuluzayo, phakathi kwezinto ezirhubuluzayo nezincancisayo, izilwanyana ezinkulu nezo zincinane kangangokuba kunzima ukuqonda ixesha eyenzeka ngalo inguqulelo.”
La mazwi akacengi solalaphi yaye ayothusa. Ngoba? Ngowama-2004, iNational Geographic yachaza ubungqina bamathambo akudala ‘njengefilimu yendaleko enemifanekiso eli-1 000 nelahlekelwe yengama-999.’ Ngaba umfanekiso omnye oseleyo “kwimifanekiso” eliwaka usenokuba bubungqina benkqubo yokuguquka okukhulu kwendaleko? Enyanisweni yintoni eboniswa ngamathambo akudala? UNiles Eldredge, unondaleko ozingomb’ isifuba uyavuma ukuba le ngxelo ibonisa ukuba kangangexesha elide “incinane okanye akukho nguqulelo indaleko eyenzileyo kwinkoliso yezinto eziphilayo.”
Ukuza kuthi ga ngoku, izazinzulu ehlabathini lonke ziye zafumana amathambo amakhulu ezilwanyana zakudala anokuba zizigidi ezingama-200 namawaka ezigidi zamathambo amancinane. Abaphengululi abaninzi bayavuma ukuba le nkcazelo ininzi neneenkcukacha ibonisa ukuba zonke iindidi eziphambili zezilwanyana zabakho ngequbuliso yaye phantse zange ziguquke, yaye iindidi ezininzi zaphela ngequbuliso ngendlela ezabakho ngayo. Emva kokuhlolisisa ubungqina bamathambo ezinto zakudala, isazi ngebhayoloji uJonathan Wells ubhala esithi: “Xa kuqwalaselwa izinto ngokohlobo lwazo, iintlanga neendidi zazo, akukhange kubonakale mahluko uphawulekayo. Ukwenza isigqibo ngokusuka kumathambo ezinto zakudala nendlela eziyileke ngayo akuyongcamango exhaswa kangako.”
Indaleko—Ngaba Yinyaniso Okanye Yintsomi?
Kutheni oonondaleko abaninzi nabaziwayo begxininisa kwelokuba ukuguquka okukhulu kwendaleko kuyinto eyenzekayo? Emva kokugxeka ezinye zeengcamango zikaRichard Dawkins, uRichard Lewontin, isazi esivunyiweyo sendaleko wabhala esithi izazinzulu ezininzi zikhetha ukwamkela iingcamango zenzululwazi ezingekho ngqiqweni “kuba sinembopheleleko, imbopheleleko yokukholelwa into esiyibonayo.” * Izazinzulu ezininzi azifuni nokuva ngoMdali olumkileyo, njengokuba uLewontin esitsho, “asifuni nokuba uThixo abek’ umcondo wakhe apha.”
Ngokuphathelele oku, isazi ngentlalo uRodney Stark kwiScientific American kuthiwa wathi: “Kangangeminyaka engama-200 abantu bebekhuthazwa ukuba xa befuna ukuba zizazinzulu bafanele bawaphephe amakhamandela onqulo.” Wongezelela esithi kwiiyunivesithi ekwenziwa kuzo uphando, “amakholwa athula ngathi akakho,” ngoxa “abahedeni bewabek’ amabala.” Ngokutsho kukaStark, “[izazinzulu] eziphambili zibathanda gqitha abahedeni.”
Ukuba uyamkela njengeyinyaniso imfundiso yokuguquka okukhulu kwendaleko, umele ukholelwe ukuba izazinzulu ezithi uThixo akanakwaziwa nezithi uThixo akakho azinakuvumela iinkolelo zazo ziphembelele uphando lwazo lwenzululwazi. Umele ukholelwe ukuba zonke izinto ezintsonkothileyo eziphilayo zibekho ngokuguquka kwemizila yemfuza nokuzikhethela kwemvelo, nangona uphando lweminyaka elikhulu, ukuhlolisisa amawaka ezigidi ezinto ekuthiwa ziguqukile kubonisa ukuba akukhange kuguqule nanye into yantsha ngokupheleleyo. Umele ukholelwe ukuba zonke izidalwa ziguquke ngokuthe ngcembe zisuka kukhokho omnye, nangona amathambo ezinto zakudala ebonisa ukuba inkoliso yezinto eziphilayo yavela ngequbuliso yaye ayizange iguquke ize ibe yenye into, nakwixesha elide ngaphambili. Ngaba ukukholelwa okunjalo kubonakala kusekelwe kubungqina obuyinyaniso? Okanye, ngaba kukukholelwa intsomi?
[Imibhalo esemazantsi]
^ isiqe. 3 Abafuyi bezinja banokuzikhetha izinja abafuna zidibane nezinja zabo ukuze zibe namantshontsho anemilenze emifutshane okanye uboya obude kunabazali. Noko ke, lo mahluko ezinjeni udla ngokubangelwa kukungabikho kwemizila ethile yemfuza. Ngokomzekelo, ingqeqe iba ncinane ngenxa yokungakhuli kakuhle kwentlala emathanjeni, nto leyo ebangela ubufutshane.
^ isiqe. 4 Ngoxa igama elithi “izinto eziphilayo” lisetyenziswe ngokufuthi kweli nqaku, kufanele kuphawulwe ukuba eli binzana alifumaneki eBhayibhileni, yona esebenzisa igama elibanzi elithi ‘uhlobo.’ Oko izazinzulu zidla ngokukubiza ngokuthi yindaleko yezinto ezintsha eziphilayo, enyanisweni lolunye nje udidi loko ingxelo yeGenesis ikubiza ngokuthi ‘luhlobo.’
^ isiqe. 6 Bona ibhokisi ethi “Zahlulahlulwa Njani Izinto Eziphilayo?”
^ isiqe. 11 Uphando lubonisa ukuba indlela iseli eyileke ngayo, inwebu yayo, nezinye izinto eziyibumbayo inendima ekuyilweni kwento ephilayo.
^ isiqe. 13 Kweli nqaku uLönnig uvakalisa izimvo zakhe ingezizo ezeMax Planck Institute for Plant Breeding Research.
^ isiqe. 14 Amathuba okuvelisa iindidi ezintsha zezityalo ngokuguqula imizila yemfuza ngokuphindaphindiweyo ayencipha, kunoko kwavela izityalo ezifanayo kunokuveliswa kwezintsha. Ngokuphuma koku, lo kaLönnig wamisela “umthetho wokuguquka okufanayo.” Ukongezelela, izityalo ezingaphantsi kwesinye ekhulwini ezaguqulwa imizila yemfuza zakhethwa ukuze kwenziwe kuzo uphando olungakumbi, yaye zingaphantsi kwesinye ekhulwini ekwafunyaniswa ukuba zingathengiswa. Kwenzeka amanyundululu angaphezu kwalawo enzeka kwizityalo kwiphulo lokuguqula imizila yemfuza kwizilwanyana, kangangokuba loo nkqubo yayekwa ngokupheleleyo.
^ isiqe. 29 Ukukholelwa kwinto ebonakalayo kule meko, kuthetha ukuba nantoni na ebonakalayo, yaye nantoni na emhlabeni wonke, kuquka izinto eziphilayo, zizivelele, kungakhange kubekho mntu onamandla angaphezu kwawemvelo.
[Amagama acatshulweyo akwiphepha 15]
“Ukuguqulwa kwemizila yemfuza akunakuguqula [isityalo okanye isilwanyana] sibe yinto entsha ngokupheleleyo”
[Amagama acatshulweyo akwiphepha 16]
Oononkxwe bakaDarwin bangqina ukuba izinto eziphilayo zizivumelanisa nokuguquka kwemozulu
[Amagama acatshulweyo akwiphepha 17]
Amathambo ezinto zakudala angqina ukuba zonke izilwanyana eziphambili zavela ngequbuliso yaye phantse azizange ziguquke
[Isicangca esikwiphepha 14]
(Ukuba ufuna inkcazelo ehlahlelwe kakuhle, yiya kwimpapasho)
INDLELA EZAHLULWA NGAYO IZINTO EZIPHILAYO
Izinto eziphilayo zahlulwa zibe ngamaqela amakhulu, ukususela kwizidalwa ezithile ukusa kumaqela amakhulu. * Ngokomzekelo, khawuthelekise indlela abantu neempukane ezidweliswe ngezantsi.
ABANTU IIMPUKANE EZINKULU
Iindidi zezinto
eziphilayo Abantu melanogaster
Uhlobo Banamhlanje Drosophila
Umnombo Izidalwa ezanyisayo Drosophilids
ezikwaziyo nokuma
ngemilenze emibini
Uhlelo Abantu nezilwanyana Diptera
ezingathi ngabantu
ezanyisayo
Udidi Izilwanyana ezanyisayo Izinambuzane
Inzala Izidalwa ezinethambo Arthropods
lomnqonqo
Iqela Elikhulu Izilwanyana Izilwanyana
[Umbhalo osemazantsi]
^ isiqe. 49 Phawula ukuba: KwiGenesis isahluko 1 kuthiwa izityalo nezilwanyana zaziya kuvelisa “ngohlobo lwazo.” (Genesis 1:12, 21, 24, 25) Noko ke, ibinzana leBhayibhile elithi “ngohlobo” alinanto yakwenza nenzululwazi yaye alifanele libhidaniswe negama lenzululwazi elithi “iindidi zezinto eziphilayo.”
[Inkcazelo]
Isicanga esisekelwe kwincwadi ethi Icons of Evolution—Science or Myth? Why Much of What We Teach About Evolution Is Wrong, kaJonathan Wells.
[Imifanekiso ekwiphepha 15]
Impukane enkulu eveliswe ngokuguqulwa kwemizila yemfuza (ngasentla), ngoxa icekethekile, iseyimpukane
[Inkcazelo]
© Dr. Jeremy Burgess/Photo Researchers, Inc.
[Imifanekiso ekwiphepha 15]
Kumalinge aphindaphindiweyo okuguqula imizila yemfuza yesityalo kufunyaniswa ukuba izityalo ezitsha ziye zancipha, ngoxa uhlobo lwesityalo esiguqulwayo besiqhubeka sivela. (Isityalo esiguqulwe imizila yemfuza sibonakala sineentyatyambo ezinkulu)
[Inkcazelo Ngomfanekiso okwiphepha 13]
From a Photograph by Mrs. J. M. Cameron/U.S. National Archives photo
[Inkcazelo Ngomfanekiso okwiphepha 16]
Iintloko zoononxwe: © Dr. Jeremy Burgess/Photo Researchers, Inc.
[Inkcazelo Ngemifanekiso ekwiphepha 17]
Idinosaur: © Pat Canova/Index Stock Imagery; izinto zakudala: GOH CHAI HIN/AFP/Getty Images