. ▁and ▁Mrs . ▁Ng ab ir ano . ▁ ▁See ▁also ▁ ▁References ▁ ▁External ▁links ▁ ▁Super mark ets ▁K ick ing ▁Local ▁Baker ies ▁Out ▁of ▁Business ▁ ▁Category : Super mark ets ▁of ▁U g anda ▁Category : Ret ail ▁companies ▁established ▁in ▁ 1 9 9 7 ▁Category : 1 9 9 7 ▁establish ments ▁in ▁U g anda ▁Category : Comp an ies ▁based ▁in ▁K amp ala <0x0A> </s> ▁Product ▁e cos ystem ▁theory ▁is ▁an ▁emer ging ▁theory ▁that ▁describes ▁how ▁the ▁design ▁of ▁manufact ured ▁products ▁evol ves ▁over ▁time ▁and ▁draw s ▁par alle ls ▁with ▁how ▁species ▁evol ve ▁within ▁a ▁natural ▁e cos ystem . ▁Fund amental ▁to ▁this ▁theory ▁is ▁that ▁manufact ured ▁product ▁lines ▁respond ▁to ▁external ▁thre ats ▁and ▁opportun ities ▁in ▁much ▁the ▁same ▁way ▁that ▁species ▁respond ▁to ▁thre ats ▁and ▁opportun ities . ▁Compet ition ▁and ▁other ▁environmental ▁press ures ▁may ▁cause ▁a ▁species ▁to ▁become ▁ext inct . ▁An ▁example ▁of ▁the ▁parallel ▁in ▁consumer ▁products ▁is ▁the ▁way ▁in ▁which ▁the ▁type writer ▁became ▁disp la ced ▁( or ▁ext inct ) ▁due ▁to ▁press ures ▁from ▁the ▁personal ▁computer . ▁ ▁Product s ▁lines ▁can ▁be ▁seen ▁to ▁increment ally ▁change ▁and ▁branch ▁over ▁time ▁following ▁the ▁principle ▁of ▁ph y let ic ▁grad ual ism . ▁Or ▁they ▁can ▁be ▁seen ▁to ▁have ▁periods ▁of ▁st asis ▁followed ▁by ▁dis rupt ive ▁innov ation . ▁This ▁follows ▁the ▁principle ▁of ▁pun