475Glossary
acid deposition A type of air pollution that includes sulfuric and nitric
acids in precipitation, as well as dry acid particles that settle out
of the air.
acid mine drainage Pollution caused when sulfuric acid and
dangerous dissolved materials such as lead, arsenic, and
cadmium wash from mines into nearby lakes and streams.
active solar heating A system of putting the sun’s energy to use
in which collectors absorb solar energy and pumps or fans
distribute the collected heat.
acute toxicity Adverse effects that occur within a short period after
high-level exposure to a toxicant.
age structure The number and proportion of people at each age in a
population.
air pollution Various chemicals (gases, liquids, or solids) present in
the atmosphere in high enough levels to harm humans, other
organisms, or materials.
aquaculture The growing of aquatic organisms (fishes, shellfish, and
seaweeds) for human consumption.
aquifer depletion The removal of groundwater faster than it can be
recharged by precipitation or melting snow.
artificial eutrophication Overnourishment of an aquatic ecosystem
by nutrients such as nitrates and phosphates due to human
activities such as agriculture and discharge from sewage
treatment plants.
atmosphere The gaseous envelope surrounding Earth.
benthic environment The ocean floor, which extends from the
intertidal zone to the deep-ocean trenches.
biocentric preservationist A person who believes in protecting
nature from human interference because all forms of life deserve
respect and consideration.
biochemical oxygen demand (BOD) The amount of oxygen that
microorganisms need to decompose biological wastes into
carbon dioxide, water, and minerals.
biodiversity hotspots Relatively small areas of land that contain an
exceptional number of endemic species and are at high risk from
human activities.
biological diversity The number and variety of Earth’s organisms;
consists of three components: genetic diversity, species richness,
and ecosystem diversity.
biological diversity The number and variety of Earth’s organisms.
biological magnification The increase in toxicant concentrations
as a toxicant passes through successive levels of the food
chain.
biomass Plant and animal material used as fuel.
biome A large, relatively distinct terrestrial region with similar
climate, soil, plants, and animals, regardless of where it occurs in
the world.
biosphere The layer of Earth that contains all living organisms.
biotic potential The maximum rate at which a population could
increase under ideal conditions.
boreal forest A region of coniferous forest (such as pine, spruce, and
fir) in the Northern Hemisphere; located just south of the tundra.
Also called taiga.
broad-spectrum pesticide A pesticide that kills a variety of
organisms, including beneficial organisms, in addition to the
target pest.
bycatch The fishes, marine mammals, sea turtles, seabirds, and
other animals caught unintentionally in a commercial fishing
catch.
carbon management Ways to separate and capture the CO 2
produced during the combustion of fossil fuels and then
sequester (store) it.
carcinogen Any substance (for example, chemical, radiation, virus)
that causes cancer.
carrying capacity ( K ) The largest population a particular environment
can support sustainably (long term), if there are no changes in that
environment.
chaparral A biome with mild, moist winters and hot, dry summers;
vegetation is typically small-leaved evergreen shrubs and small
trees.
chlorofluoro-carbons (CFCs) Human-made organic compounds that
contain chlorine and fluorine; now banned because they attack
the stratospheric ozone layer.
chronic toxicity Adverse effects that occur after a long period of
low-level exposure to a toxicant.
clear-cutting A logging practice in which all the trees in a stand of
forest are cut, leaving just the stumps.
climate The typical weather patterns that occur in a place over a
period of years.
cogeneration (CHP) An energy technology that involves recycling
“waste” heat.
command and control regulation Pollution control laws that work by
setting limits on levels of pollution.
community A natural association that consists of all the populations
of different species that live and interact together within an area
at the same time.
compact development Design of cities in which tall, multiple-unit
residential buildings are close to shopping and jobs, and all are
connected by public transportation.
competition The interaction among organisms that vie for the same
resources in an ecosystem (such as food or living space).
conservation biology The scientific study of how humans affect
organisms and of the development of ways to protect biological
diversity.
conservation easement A legal agreement that protects privately
owned forest, rangeland, or other property from development for
a specified number of years.
conservation tillage A method of cultivation in which residues
from previous crops are left in the soil, partially covering it and
helping to hold it in place until the newly planted seeds are
established.
contour plowing Plowing that matches the natural contour of the
land.
Coriolis effect The tendency of moving air or water to be deflected
from its path and swerve to the right in the Northern Hemisphere
and to the left in the Southern Hemisphere.
cost–benefit diagram A diagram that helps policy makers make
decisions about costs of a particular action and benefits that
would occur if that action were implemented.
crop rotation The planting of a series of different crops in the same
field over a period of years.