Population:

Population is a group of individuals of the same species which resides in a particular geographical area at a particular time and functions as a unit. For example, Indian population of humans will include all human beings living in India at a particular time.

Community:

Community is a group of individuals of different species, living within a certain geographical area. For example, a forest of trees and undergrowth plants, inhabited by animals and rooted in soil containing bacteria and fungi, constitutes a biological community. Individuals in a community can be similar or dissimilar, but they cannot reproduce with the members of other species.