ecologist - a scientist concerned with the interrelationship of organisms and their environment.

ecology - a branch of science concerned with the interrelationship of organisms and their environment.

ecosystem - an interconnected and symbiotic grouping of animals, plants, fungi, and microorganisms.

edge cities - cities bounded by water, usually with eroding or polluted waterfront areas.

efficiency - see energy efficiency.

electric vehicles - vehicles which use electricity (usually derived from batteries recharged from electrical outlets) as their power source.

emissions cap - a limit on the amount of greenhouse gases that a company or country can legally emit.

endangered species - species in danger of extinction throughout all or a significant part of its range.

endocrine disruptors - substances that stop the production or block the transmission of hormones in the body.

energy conservation - using energy efficiently or prudently; saving energy.

energy efficiency - technologies and measures that reduce the amount of electricity and/or fuel required to do the same work, such as powering homes, offices and industries.

enrolled bill - the final, certified bill sent to the President; House and Senate versions of a bill must match exactly in order to be enrolled.

equity - in the environmental sense, the planned dispersement of toxic or waste facilities in regions throughout the socioeconomic strata.

estuary - a bay or inlet, often at the mouth of a river, in which large quantities of freshwater and seawater mix together. These unique habitats are necessary nursery grounds for many marine fishes and shellfishes.

eugenics - the study of hereditary improvement of the human race by controlled selective breeding.

Everglades - large and biologically diverse wetland ecosystem in South Florida.

executive session - a congressional meeting closed to the public (and the media).

exurbia - (1) the area of suburbs; (2) the region outside a city and its suburbs where wealthier families live.