ers ▁from ▁North ▁Rh ine - West phal ia <0x0A> </s> ▁F ec und ity ▁is ▁defined ▁in ▁two ▁ways ; ▁in ▁human ▁dem ography , ▁it ▁is ▁the ▁potential ▁for ▁reprodu ction ▁of ▁a ▁recorded ▁population ▁as ▁opposed ▁to ▁a ▁sole ▁organ ism , ▁while ▁in ▁population ▁bi ology , ▁it ▁is ▁considered ▁similar ▁to ▁ ▁fert ility , ▁the ▁natural ▁cap ability ▁to ▁produce ▁off spring , ▁measured ▁by ▁the ▁number ▁of ▁gam etes ▁( eg gs ), ▁seed ▁set , ▁or ▁a sex ual ▁propag ules . ▁A ▁lack ▁of ▁fert ility ▁is ▁infer til ity ▁while ▁a ▁lack ▁of ▁f ec und ity ▁would ▁be ▁called ▁ster ility . ▁ ▁Human ▁dem ography ▁cons iders ▁only ▁human ▁f ec und ity , ▁at ▁its ▁cult ur ally ▁differ ing ▁rates , ▁while ▁population ▁bi ology ▁studies ▁all ▁organ isms . ▁The ▁term ▁f ec und ity ▁in ▁population ▁bi ology ▁is ▁often ▁used ▁to ▁describe ▁the ▁rate ▁of ▁off spring ▁production ▁after ▁one ▁time ▁step ▁( o ften ▁annual ). ▁In ▁this ▁sense , ▁f ec und ity ▁may ▁include ▁both ▁birth ▁rates ▁and ▁surv ival ▁of ▁young ▁to ▁that ▁time ▁step . ▁While ▁levels ▁of ▁f ec und ity ▁vary ▁ge ograph ically , ▁it ▁is ▁generally ▁a ▁consistent ▁feature ▁of ▁each ▁culture . ▁F ec und ation ▁is ▁another ▁term ▁for ▁fert il ization . ▁Super f ec und ity ▁or ▁retro f ec und ity ▁refers ▁to ▁an ▁organ ism ' s ▁ability ▁to ▁store ▁another