Principles of Ecology Organisms and Their Environment What is Ecology? Ecology: the study of interactions that take place between organisms and their environment The Biosphere Biosphere: the part of Earth that supports life The biosphere includes the top portion of Earth?s crust, all the waters that cover Earth?s surface, and the atmosphere that surrounds Earth. The biosphere is made up of different environments that are home to different kinds of organisms. Ecosystem: all the living organisms living in an area and the nonliving features of their environment Biotic factors: living organisms in an ecosystem (ex. bison, grass, birds, insects) Abiotic factors: nonliving features of an ecosystem (ex. water, temperature, sunlight, soil, air) Levels of Organization