E

Earth's average temperature: the temperature of the planet as averaged from thousands of readings taken from thermometers on weather stations, ships and balloons, as well as from satellites that measure microwave radiation emitted from oxygen molecules which vary according to temperature.

Ebola: a severe, infectious and often fatal disease in humans and other primates (monkeys and chimpanzees) caused by the Ebola virus; characterized by high fever and severe internal bleeding.

eco-label: a seal or logo suggesting that a product is environmentally friendly.

ecological community: biotic communities that are identified through a combination of parameters including species composition, structure and habitat.

ecological footprint: a calculation that estimates the area of Earth's productive land and water required to supply the resources that an individual or group demands, as well as to absorb the wastes that the individual or group produces.

ecological or ecosystem services: valuable services provided by natural systems. Examples of ecological services include flood control, air purification and climate control.

ecological restoration: the process whereby an entire ecosystem is brought back to health.

ecoregion: a relatively large unit of land or water that is characterized by a distinctive climate, ecological features and plant and animal communities e.g., Everglades Flooded Grasslands and the Great Basin Lakes and Streams.

ecosystem: a community of plants, animals and microorganisms that are linked by energy and nutrient flows and that interact with each other and with the physical environment. Rain forests, deserts, coral reefs, grasslands and a rotting log are all examples of ecosystems.

ecotoxicology: an area of study that examines the connection between environmental health and human health.

effluent: an outflowing of liquid waste into a body of water.

emissions: release of pollutants into the air from a source.

endangered species: species threatened with extinction. The Florida panther and the California condor are both examples of endangered species.

endemic: describes an animal or plant species that naturally occurs in only one area or region. For example, the redfin darter is a fish endemic to the rivers of the Ozark forests and the Joshua tree is a plant endemic to the Mojave Desert.

endocrine disruptors: substances that stop the production or block the transmission of hormones in the body and often interfere with development.

endocrine system: an integrated system of organs within the body that through the release of hormones controls tissue function, metabolism, growth, puberty and development.

Energy Star: a program of the US Government that certifies and labels products that are energy efficient.

environmental health: wellbeing based on the health of the surrounding environment.

epicenter: the point on Earth's surface directly above the focus of an earthquake.

epidemiologist: one who studies the presence of disease in populations.

epiphany: the feast on the 6th of January associated with the visit of the three wise men to the infant Jesus; the 12th day of Christmas; a sudden, intuitive realization through an ordinary circumstance.

erosion: wearing away of the land by the action of water, ice or wind.

estrogen: a female hormone produced by the ovaries responsible for secondary sexual characteristics in females and for the preparation of the uterus for implantation of the fertilized egg.

ethanol: the alcohol, found in alcoholic beverages, produced by the fermentation of sugars from such crops as corn. Currently being trialed as a replacement fuel for petroleum

euphausiids: tiny crustaceans that resemble shrimp from the genus Euphausia, whose literal definition translates to "whale food."

evolution: the process of change in the traits of organisms or populations over time. Evolution, through the process of natural selection, can lead to the formation of new species.

excess nutrients: the over abundance of certain chemicals, typically nitrogen and phosphorous in an ecosystem. In marine environments, this is usually caused by excess fertilizer runoff, creating algal blooms and leading to dead zones.

exhaust: gases ejected from an engine as waste products.

exotic species: introduced species not native or endemic to the area in question.

externalities: in economics, benefits or costs that are not included in the market price of goods or services. For example, the cost of natural resource depletion, pollution and other environmental and social factors are externalities that often are not factored into the market price of a product.

extinct: refers to a species that no longer exists. Local extinction occurs when every member of a particular population has died. Global extinction occurs when every member of a species has died. The passenger pigeon and the dodo are examples of globally extinct birds.