All of the living and nonliving things in an area and their interactions .
Ecosystem
All the members of a species living in a certain area .
Population
All the different living organisms that live and interact in an area.
Community
The way an organism interacts with living and nonliving things in its ecosystem .
NIche
The close association of members of different species that live together .
Symbiosis
The gradual replacement of one community by another over time .
Succession