Glossary - Environmental Science - page 323

drift netting The practice of dragging large nets through the water to catch fish.
Dust Bowl A period in the 1930s in the Midwestern United States during which drought and overuse of the
land led to dust storms and desertification.
earthquakes Vibrations in the Earth's crust due to plate movements created by the sudden release of pressure
built up at plate boundaries. Localized earthquakes also can be due to magma intrusions in volcanic areas.
ecological pyramids Diagrams that are used to show relative biomass or productivity (and, thus, energy loss)
at each trophic level in an ecosystem; also called energy pyramids.
ecological succession The process by which a community of plants and animals replaces a less complex com-
munity of plants and animals or develops in an uninhabited area.
economics The production, distribution, regulation, and consumption of goods and services.
ecosystem The interconnected interactions of all living and nonliving things in a specific area at the same time.
ecosystem services Services provided by our ecosystems that help to support life on Earth.
ED 50 The dose of a substance at which 50 percent of a test population is affected.
El Niño The warming phase of ENSO in the eastern Pacific Ocean, accompanied by higher air surface pressure
in the western Pacific Ocean.
El Niño/La Niña-Southern Oscillation cycle (ENSO) A periodic climate pattern in the tropical Pacific Ocean
with an approximately five-year cycle (varying from three to seven years), characterized by variations in the
surface temperature of the tropical eastern Pacific Ocean and the air pressure in the tropical western Pacific
Ocean.
electric cars Cars that run solely on electricity stored in batteries.
electrical energy Energy produced by the movement of electrons, typically moving through a wire. Usable
electrical energy is produced by a generator in which relative motion of coiled copper wire and a magnetic
field results in a flow of electrons.
electromagnetic energy Nonmechanical energy that travels in waves, including the entire electromagnetic
spectrum, from low-energy radio waves, through microwaves, ultraviolet waves, through the visible light spec-
trum (ROYGBIV), through the ultraviolet waves, X-rays, and highest-energy gamma rays.
emissions Common term for the gases discharged into the atmosphere from burning of fossil fuels. The
primary sources include coal and natural gas electric power plants and emissions from transportation (cars,
trucks, buses, trains, and planes).
endemic Localized, or occurring only in one location on the planet; commonly used to describe species that
live in only one place.
endocrine disruptor A substance that alters the hormone (endocrine) system by binding to substances that
would normally bind specific hormones, thus blocking the hormone and impeding normal reactions.
environmental resistance All limiting factors acting on a population, restricting an organism's biological po-
tential.
epicenter The point directly above the focus of an earthquake.