Duba wurin da ke ƙasa sannan ka amsa tambayar daga baya a cikin harshe ɗaya kamar yadda wurin yake:  Passage: Ka'idar Darwin game da zabin yanayi ta kafa tushe don ka'idar juyin halitta ta zamani, kuma gwaje-gwajensa da lura sun nuna cewa kwayoyin halitta a cikin al'ummomi sun bambanta da juna, cewa wasu daga cikin waɗannan bambance-bambancen an gada, kuma waɗannan bambance-bambance na iya aiki ta hanyar zabin yanayi. Amma, bai iya bayyana tushen waɗannan bambancin ba. Kamar yawancin magabatansa, Darwin yayi kuskuren tunanin cewa halaye na gado sun kasance samfurin amfani da rashin amfani, kuma cewa halaye da aka samu yayin rayuwar kwayar halitta za a iya ba da su ga zuriyarsa. Ya nemi misalai, kamar manyan tsuntsayen da ke cin abinci a ƙasa suna samun kafafu masu ƙarfi ta hanyar motsa jiki, da kuma fuka-fuki marasa ƙarfi daga rashin tashi har sai, kamar tsuntsu, ba za su iya tashi ba. Wannan rashin fahimta an kira shi gadon halayen da aka samu kuma ya kasance wani ɓangare na ka'idar canzawa na jinsunan da Jean-Baptiste Lamarck ya gabatar a 1809. A ƙarshen ƙarni na 19 wannan ka'idar ta zama sananne da Lamarckism. Darwin ya samar da ka'idar da ba ta yi nasara ba ya kira pangenesis don ƙoƙarin bayyana yadda za a iya samun halaye da aka samu. A cikin shekarun 1880s gwaje-gwajen August Weismann ya nuna cewa canje-canje daga amfani da rashin amfani ba za a iya gada ba, kuma Lamarckism a hankali ya faɗi daga tagomashi. Bayanan da suka ɓace da ake buƙata don taimakawa wajen bayyana yadda sabbin halaye za su iya wucewa daga iyaye zuwa ga zuriyarsa an samar da su ta hanyar aikin kwayoyin halitta na Gregor Mendel. Gwaje-gwajen Mendel tare da tsararraki da yawa na tsire-tsire masu tsire-tsire sun nuna cewa gadon yana aiki ta hanyar rarrabewa da sake canza bayanan gado yayin ƙirƙirar ƙwayoyin jima'i da sake haɗa wannan bayanin yayin haifuwa. Wannan kamar hada hannaye daban-daban na katunan wasa, tare da kwayoyin da ke samun haɗuwa ta bazuwar rabin katunan daga mahaifa ɗaya, da rabin katunan daga ɗayan. Mendel ya kira bayanan bayanai; duk da haka, daga baya sun zama sanannun kwayoyin halitta. Kwayoyin halitta sune ainihin raka'a na gado a cikin halittu masu rai. Suna ƙunshe da bayanan da ke jagorantar jiki...  Tambaya: Mene ne Mendel ya kira kwayoyin halitta?
abubuwan da suka shafi bayanai