Ecology (from Greek: οἶκος, "house", or "environment"; -λογία, "study of") is the branch of biology which studies the interactions among organisms and their environment. Objects of study include interactions of organisms with each other and with abiotic components of their environment. Topics of interest include the biodiversity, distribution, biomass, and populations of organisms, as well as cooperation and competition within and between species. Ecosystems are dynamically interacting systems of organisms, the communities they make up, and the non-living components of their environment. Ecosystem processes, such as primary production, pedogenesis, nutrient cycling, and niche construction, regulate the flux of energy and matter through an environment. These processes are sustained by organisms with specific life history traits. Biodiversity means the varieties of species, genes, and ecosystems, enhances certain ecosystem services.
The disruption of the world's ecological systems — from the rise of global warming and the consequent damage to our climate balance, to the loss of living species and the depletion of ocean fisheries and forest habitats — continues at a frightening rate. Practically every day, it becomes clearer to us that must act now to protect our Earth, while preserving and creating jobs for our people.
Al Gore, Address to the International Press Institute, Boston, Massachusetts (30 April 2000.
The study of public administration must include its ecology. "Ecology," states the Webster Dictionary, "is the mutual relations, collectively, between organisms and their environment." J. W. Bews points out that "the word itself is derived from the Greek oikos a house or home, the same root word as occurs in economy and economics. Economics is a subject with which ecology has much in common, but ecology is much wider. It deals with all the inter-relationships of living organisms and their environment." Some social scientists have been returning to the use of the term, chiefly employed by the biologist and botanist, especially under the stimulus of studies of anthropologists, sociologists, and pioneers who defy easy classification, such as the late Sir Patrick Geddes in Britain.
John M. Gaus, Reflections on public administration, 1947, p. 6