Glossary 477monoculture Ecological simplification in which only one type of plant
is cultivated over a large area.
municipal solid waste Solid materials discarded by homes, offices,
stores, restaurants, schools, hospitals, prisons, libraries, and
other commercial and institutional facilities.
national income accounts Measures of the total income of a nation’s
goods and services for a given year.
natural capital Earth’s resources and processes that sustain living
organisms, including humans; includes minerals, forests, soils,
water, clean air, wildlife, and fisheries.
natural selection The tendency of better-adapted individuals—those
with a combination of genetic traits best suited to environmental
conditions—to survive and reproduce, increasing their proportion
in the population.
neritic province The part of the pelagic environment that overlies the
ocean floor from the shoreline to a depth of 200 m (650 ft).
nonmunicipal solid waste Solid waste generated by industry,
agriculture, and mining.
nonpoint source pollution Pollution that enters bodies of water over
large areas rather than being concentrated at a single point of
entry.
nonrenewable resources Natural resources that are present in limited
supplies and are depleted as they are used.
nuclear energy The energy released by nuclear fission or fusion.
nuclear reactor A device that initiates and maintains a controlled
nuclear fission chain reaction to produce energy for electricity.
nutrient cycling The pathway of various nutrient minerals or
elements from the environment through organisms and back to
the environment.
oceanic province The part of the pelagic environment that overlies
the ocean floor at depths greater than 200 m (650 ft).
optimum amount of pollution The amount of pollution that is
economically most desirable.
overburden Soil and rock overlying a useful mineral deposit.
overgrazing A situation that occurs when too many grazing animals
consume the plants in a particular area, leaving the vegetation
destroyed and unable to recover.
overnutrition A type of malnutrition in which an overconsumption of
calories leaves the body susceptible to disease.
ozone thinning The removal of ozone from the stratosphere by
human-produced chemicals or natural processes.
passive solar heating A system of putting the sun’s energy to use
that does not require mechanical devices to distribute the
collected heat.
pathogen An agent (usually a microorganism) that causes disease.
persistent organic pollutants (POPs) Persistent toxicants that
bioaccumulate in organisms and travel through air and water to
contaminate sites far from their source.
pesticide A toxic chemical used to kill pests.
photochemical smog A brownish-orange haze formed by
chemical reactions involving sunlight, nitrogen oxides, and
hydrocarbons.
photosynthesis The biological process that captures light energy
and transforms it into the chemical energy of organic molecules,
which are manufactured from carbon dioxide and water.
photovoltaic (PV) solar cell A wafer or thin film of solid-state
materials, such as silicon or gallium arsenide, that is treated withgrowth rate (r) The rate of change (increase or decrease) of a
population’s size, expressed in percentage per year.
gyres Large, circular ocean current systems that often encompass an
entire ocean basin.
habitat corridor A protected zone that connects isolated unlogged
or undeveloped areas.
habitat fragmentation The breakup of large areas of habitat into
small, isolated patches.
hazardous waste A discarded chemical that threatens human health
or the environment.
high-level radioactive wastes Radioactive solids, liquids, or gases
that initially give off large amounts of ionizing radiation.
highly developed countries Countries with complex industrialized
bases, low rates of population growth, and high per person
incomes.
hydraulic fracturing The use of pressurized water and chemicals to
extract natural gas from deep layers of shale.
hydropower A form of renewable energy that relies on flowing or
falling water to generate electricity.
incentive-based regulation Pollution control laws that work by
establishing emission targets and providing industries with
incentives to reduce emissions.
industrialized agriculture Modern agricultural methods that require
large capital inputs and less land and labor than traditional
methods.
infant mortality rate The number of deaths of infants under age 1 per
1000 live births.
infrared radiation Electromagnetic radiation with wavelengths longer
than those of visible light but shorter than microwaves; perceived
as invisible waves of heat.
integrated waste management A combination of the best waste
management techniques into a consolidated program to deal
effectively with solid waste.
intertidal zone The area of shoreline between low and high tides.
invasive species Foreign species that spread rapidly in a new area if
free of predators, parasites, or resource limitations that may have
controlled their population in their native habitat.
landscape A region that includes several interacting ecosystems.
less developed countries Countries with low levels of industrialization,
very high rates of population growth, very high infant mortality
rates, and very low per person incomes relative to highly
developed countries.
low-level radioactive wastes Solids, liquids, or gases that give off
small amounts of ionizing radiation.
marginal cost of pollution abatement The added cost of reducing one
unit of a given type of pollution.
marginal cost of pollution The added cost of an additional unit of
pollution.
mass burn incinerator A large furnace that burns all solid waste
except for unburnable items such as refrigerators.
microirrigation A type of irrigation that conserves water by piping it
to crops through sealed systems.
minerals Elements or compounds of elements that occur naturally in
Earth’s crust.
moderately developed countries Countries with medium levels of
industrialization and per person incomes lower than those of
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