Ma'anar ƙamus na kalmar "yankin biogeographical" yanki ne na yanki wanda ke da nau'in nau'in tsire-tsire da dabbobi waɗanda suka samo asali a tsawon lokaci don amsa irin yanayin muhalli. Yankunan halittu galibi ana bayyana su ta hanyar haɗin kai na musamman na zahiri, yanayin yanayi, da yanayin ƙasa, waɗanda tare suka haifar da keɓaɓɓun wuraren zama waɗanda ke tallafawa nau'ikan nau'ikan daban-daban. Ana amfani da waɗannan yankuna sau da yawa a matsayin ginshiƙi don fahimtar tsarin rayayyun halittu da kuma tsara dabarun kiyayewa don karewa da sarrafa yanayin halittu. Misalai na yankuna na rayuwa sun haɗa da tundra Arctic, dajin Amazon, da Great Barrier Reef.