Ecology, as a science, is fundamentally concerned with the interaction between living things and the environment. In ecological terms, the environment is both one's physical habitat and the various other organisms that also shared the same geographic space. For example, many humans live in suburbs, which can also be home to a wide variety of birds, squirrels, rabbits and other animals.
To an ecologist, any external force, condition, or substance that can affect an organism is an ecological factor. The sum of all factors constitutes the environment. The physical place where an organisms lives is known as its habitat, a specific set of environmental conditions that are ideal for survival of that organism.
Ecologists also classify the surrounding environment in biotic and abiotic factors. Biotic factors include the other organisms one encounters, from one's own and different species. Abiotic factors included such physical conditions as temperature, atmosphere and other non-living aspects.
What is clear to ecologists is that human beings have had a tremendous impact on the environment, perhaps more than any other species on Earth. Various human activities that degrade the environment have impacted all other forms of life, including plants, animals, and even microbes. Further, human beings also affect the abiotic factors, including resource depletion and pollution.