The study of ecology is very important in the world today. Ecology is the science of the interrelations between living organisms and their environment, including both physical and biotic factors, as well as intraspecific and interspecific interactions (Carter 2001) This includes the study of populations, communities, ecosystems, and the biosphere (Carter 2001). At first plants and animals were studied separately until Victor Shelford stressed the importance of the relationship between plants and animals (Carter 2001). Then, Tansley took the idea of the relationship between plants and animals a step further in saying that they a just part of a system that also includes physical factors as well. In 1935 Tansley used the term "ecosystem" to discribe these factors as a whole (Batterbury 1997).
Ecosystems are comprised of four basic components: water, land (rocks and soil), air and living things (plants and animals including humans). Everything in an ecosystem is related to everything else. Consequently, anything that occurs in one of these basic components will have an effect on the other three. Using the idea of ecosystems is the key to achieving sustainability because an ecosystem approach places equal emphasis on concerns related to the environment, the economy and the community (Environment Canada).