Botkin Environmental Science Earth as Living Planet 8th txtbk

G-12 Glossary
Minimum viable population The minimum number of
individuals that have a reasonable chance of persisting for a
specified time period.
Missing carbon sink The unknown location of substantial
amounts of carbon dioxide released into the atmosphere
but apparently not reabsorbed and thus remaining
unaccounted for.
Mitigated negative declaration A special type of negative
declaration that suggests that the adverse environmental
aspects of a particular action may be mitigated through
modification of the project in such a way as to reduce the
impacts to near insignificance.
Mitigation A process that identifies actions to avoid, lessen, or
compensate for anticipated adverse environmental impacts.
Mobile sources Sources of air pollutants that move from place
to place; for example, automobiles, trucks, buses, and trains.
Model A deliberately simplified explanation, often physical,
mathematical, pictorial, or computer-simulated, of complex
phenomena or processes.
Monitoring Process of collecting data on a regular basis at
specific sites to provide a database from which to evaluate
change. For example, collection of water samples from
beneath a landfill to provide early warning should a
pollution problem arise.
Monoculture (Agriculture) The planting of large areas with
a single species or even a single strain or subspecies in
farming.
Moral justification for the conservation of nature An argument
for the conservation of nature on the grounds that
aspects of the environment have a right to exist, independent
of human desires, and that it is our moral obligation
to allow them to continue or to help them persist.
Multiple use Literally, using the land for more than one purpose
at the same time. For example, forestland can be used
to produce commercial timber but at the same time serve
as wildlife habitat and land for recreation. Usually multiple
use requires compromises and trade-offs, such as striking a
balance between cutting timber for the most efficient production
of trees at a level that facilitates other uses.
Mutation Stated most simply, a chemical change in a DNA
molecule. It means that the DNA carries a different
message than it did before, and this change can affect the
expressed characteristics when cells or individual organisms
reproduce.
Mutualism See Symbiosis.
Natural capital Ecological systems that provide public service
benefits.
Natural catastrophe Sudden catastrophic change in the
environment, not the result of human actions.
Natural gas Naturally occurring gaseous hydrocarbon (predominantly
methane) generally produced in association
with crude oil or from gas wells; an important efficient and
clean-burning fuel commonly used in homes and industry.
Natural hazard Any natural process that is a potential threat
to human life and property.
Natural selection A process by which organisms whose
biological characteristics better fit them to the environment are
represented by more descendants in future generations than
those whose characteristics are less fit for the environment.
Nature preserve An area set aside with the primary purpose
of conserving some biological resource.
Negative declaration A document that may be filed if an
agency has determined that a particular project will not
have a significant adverse effect on the environment.
Negative feedback A type of feedback that occurs when the
system’s response is in the opposite direction of the output.
Thus negative feedback is self-regulating.
Net growth efficiency Net production efficiency (P/A),
or the ratio of the material produced (P ) to the material
assimilated (A) by an organism. The material assimilated is
less than the material consumed because some food taken
in is egested as waste (discharged) and never used by an
organism.
Net production (biology) The production that remains after
utilization. In a population, net production is sometimes
measured as the net change in the numbers of individuals.
It is also measured as the net change in biomass or in stored
energy. In terms of energy, it is equal to the gross production
minus the energy used in respiration.
New forestry The name for a new variety of timber harvesting
practices to increase the likelihood of sustainability, including
recognition of the dynamic characteristics of forests and of
the need for management within an ecosystem context.
Niche (1) The “profession,” or role, of an organism or species;
or (2) all the environmental conditions under which the
individual or species can persist. The fundamental niche is
all the conditions under which a species can persist in the
absence of competition; the realized niche is the set of conditions
as they occur in the real world with competitors.
Nitrogen cycle A complex biogeochemical cycle responsible
for moving important nitrogen components through the
biosphere and other Earth systems. This is an extremely
important cycle because nitrogen is required by all living
things.
Nitrogen fixation The process of converting inorganic,
molecular nitrogen in the atmosphere to ammonia. In
nature it is carried out only by a few species of bacteria, on
which all life depends.
Nitrogen oxides Occur in several forms: NO, NO 2 , and
NO 3 . Most important as an air pollutant is nitrogen
dioxide, which is a visible yellow brown to reddish brown
gas. It is a precursor of acid rain and produced through the
burning of fossil fuels.
Noise pollution A type of pollution characterized by
unwanted or potentially damaging sound.
Non-linear process Characterized by system operation in
which the effect of adding a specific amount of something
changes, depending upon how much has been added
before.
Nonmarine evaporites With respect to mineral resources,
refers to useful deposits of materials such as sodium and
calcium bicarbonate, sulfate, borate, or nitrate produced by
evaporation of surficial waters on the land, as differentiated
from marine waters in the oceans.