Botkin Environmental Science Earth as Living Planet 8th txtbk

Glossary G-15
Positive feedback A type of feedback that occurs when an
increase in output leads to a further increase in output.
This is sometimes known as a vicious cycle, since the more
you have, the more you get.
Potential energy Energy that is stored. Examples include
the gravitational energy of water behind a dam; chemical
energy in coal, fuel oil, and gasoline; and nuclear energy (in
the forces that hold atoms together).
Power The amount of energy used per unit of time.
Precautionary principle The idea that even full scientific
certainty is not available to prove cause and effect, we
should still take cost-effective precautions to solve environmental
problems when appears to be a threat of potential
serious and irreversible environmental damage.
Predation-parasitism Interaction between individuals of two
species in which the outcome benefits one and is detrimental
to the other.
Predator An organism that feeds on other live organisms,
usually of other species. The term is usually applied to
animals that feed on other animals.
Premises In science, initial definitions and assumptions.
Primary pollutants Air pollutants emitted directly into
the atmosphere. Included are particulates, sulfur oxides,
carbon monoxide, nitrogen oxides, and hydrocarbons.
Primary production See Production, primary.
Primary succession The initial establishment and development
of an ecosystem.
Primary treatment (of wastewater) Removal of large particles
and organic materials from wastewater through screening.
Probability The likelinood that an event will occur.
Production, ecological The amount of increase in organic
matter, usually measured per unit area of land surface or
unit volume of water, as in grams per square meter (g/m 2 ).
Production is divided into primary (that of autotrophs) and
secondary (that of heterotrophs). It is also divided into net
(that which remains stored after use) and gross (that added
before any use).
Production, primary The production by autotrophs.
Production, secondary The production by heterotrophs.
Productivity, ecological The rate of production; that is, the
amount of increase in organic matter per unit time (for
example, grams per meter squared per year).
Prokaryote A kind of organism that lacks a true cell nucleus
and has other cellular characteristics that distinguish it
from the eukaryotes. Bacteria are prokaryotes.
Pseudoscientific Describes ideas that are claimed to have
scientific validity but are inherently untestable and/or lack
empirical support and/or were arrived at through faulty
reasoning or poor scientific methodology.
Public service functions Functions performed by ecosystems
that benefit other forms of life in other ecosystems.
Examples include the cleansing of the air by trees and
removal of pollutants from water by infiltration through
the soil.
Public trust Grants and limits the authority of government
over certain natural areas of special character.
Qualitative data Data distinguished by qualities or attributes
that cannot be or are not expressed as quantities. For ex-
ample, blue and red are qualitative data about the electromagnetic
spectrum.
Quantitative data Data expressed as numbers or numerical
measurements. For example, the wavelengths of specific
colors of blue and red light (460 and 650 nanometers,
re-spectively) are quantitative data about the electromagnetic
spectrum.
R-to-C ratio A measure of the time available for finding the
solutions to depletion of nonrenewable reserves, where R
is the known reserves (for example, hundreds of thousands
of tons of a metal) and C is the rate of consumption (for
example, thousands of tons per year used by people).
Radiation absorbed dose (RAD) Energy retained by living
tissue that has been exposed to radiation.
Radioactive decay A process of decay of radioisotopes that
change from one isotope to another and emit one or more
forms of radiation.
Radioactive waste Type of waste produced in the nuclear fuel
cycle; generally classified as high-level or low-level.
Radioisotope A form of a chemical element that spontaneously
undergoes radioactive decay.
Radionuclides Atoms with unstable nuclei that undergo
radioactive decay.
Radon A naturally occurring radioactive gas. Radon is colorless,
odorless, and tasteless and must be identified through proper
testing.
Rangeland Land used for grazing.
Rare species Species with a small total population, or
restricted to a small area, but not necessarily declining or in
danger of extinction.
Realms (ecological) Major biogeographic regions of Earth
in which most animals have some common genetic
heritage.
Record of decision Concise statement prepared by the agency
planning a proposed project; it outlines the alternatives
considered and discusses which alternatives are environmentally
preferable.
Recreational justification for the conservation of
nature An argument for the conservation of nature on the
grounds that direct experience of nature is inherently enjoyable
and that the benefits derived from it are important and
valuable to people.
Recycle To collect and reuse resources in the waste stream.
Reduce With respect to waste management, refers to practices
that will reduce the amount of waste we produce.
Reduce, reuse, and recycle The three Rs of integrated waste
management.
Renewable energy Alternative energy sources, such as solar,
water, wind, and biomass, that are more or less continuously
available in a time framework useful to people.
Renewable resource A resource, such as timber, water, or air,
that is naturally recycled or recycled by artificial processes
within a time frame useful for people.
Replacement-level fertility The fertility rate required for the
population to remain a constant size.
Representative natural areas Parks or preserves set aside to
represent presettlement conditions of a specific ecosystem
type.