Duba wurin da ke ƙasa sannan ka amsa tambayar daga baya a cikin harshe ɗaya kamar yadda wurin yake:  Passage: Tsarin halittu na Burgess Shale ya bayyana ya zama nau'i na tsakiyar Cambrian. Kodayake kwayoyin halittar da ke dauke da sashi mai wuya sun kai kashi 14% na al'umma, ana samun waɗannan kwayoyin a cikin irin wannan rabo a wasu yankuna na Cambrian. Wannan yana nufin cewa babu wani dalili da za a ɗauka cewa kwayoyin da ba su da sassa masu wuya suna da ban mamaki a kowane hanya; hakika, da yawa sun bayyana a wasu lagerstätten na shekaru daban-daban da wurare. Biota ya ƙunshi nau'ikan halittu. Abubuwan da ke yin iyo (nectonic) suna da wuya, tare da yawancin kwayoyin da ke zaune a kasa (benthic) <unk> ko dai suna motsawa (vagrant) ko kuma a haɗe da su a cikin teku (sessile). Kimanin kashi biyu bisa uku na halittun Burgess Shale sun rayu ne ta hanyar ciyar da abubuwan da ke cikin kwayoyin halitta a cikin tekun mai laka, yayin da kusan kashi uku ya tace ƙananan ƙwayoyin daga ginshikin ruwa. A karkashin kashi 10% na kwayoyin sun kasance masu farauta ko masu cinyewa, kodayake tunda waɗannan kwayoyin sun fi girma, an rarraba biomass daidai tsakanin kowane ɗayan abinci mai tacewa, ciyar da ajiya, masu farauta da masu cinyewa. Yawancin kwayoyin Burgess Shale suna wakiltar membobin rukuni na rukuni na dabbobi na zamani, kodayake wakilan ƙungiyar kambi na wasu phyla suma suna nan.  Tambaya: Mene ne kwayoyin halitta?
kewayon kwayoyin halitta