IPA: /ˌɪntərˈpɒpjʊˌleɪʃən/
KK: /ɪntərˌpɒpjʊˈleɪʃən/
Relating to or occurring between different groups of organisms or populations.
The interpopulation differences in behavior were fascinating to study.
Interpopulation → It is formed from "inter-" (meaning between) and "population" (from Latin "populatio", meaning people or population). The word refers to the interactions or relationships between different populations.
Think of 'between' ('inter-') different groups of 'people' ('population') to remember that 'interpopulation' refers to the relationships among various populations.