ecology

noun3

1. •
   The branch of biology dealing with the relationships of organisms with their environment and with each other.

   • As a graduate student, he was working on a thesis: The Ecology of the Black Creek Area. He had to investigate the relationships, past and present, of men and plants and animals in this region. — 1949
2. •
   Any study of the relationships of components of a system with their environment and with each other.
3. •
   The totality or pattern of relationships of components of a system with their environment and with each other.