The study of the interaction between organisms and their environment. Ecology is an interdisciplinary field that incorporates aspects of biology, chemistry, geology, climatology, and meteorology. The Ecologist will be an expert in the effects of climate, soil, water, geological processes, natural selection, and species population dynamics on an ecosystem. He will be able to estimate the effect that the loss of a particular species would have on an ecosystem. A significant field of study within ecology is environmentalism. The environmentalist is concerned with the negative ecological effects of human interaction with the environment, including global warming, ozone depletion, air and water pollution, acid rain, deforestation, wetland loss, solid waste disposal, and toxic chemicals and other hazardous wastes.