Acclimation - adjustment to
slowly changing new conditions.
Adaptation - any genetically
controlled structural, physiological, or behavioral characteristic
that enhances members of a population's chances of surviving and
reproducing in its environment. It usually results from a
Adaptive radiation - period of
time (usually millions of years) during which numerous new species
evolve to fill vacant and new ecological niches in changed
environments, usually after a mass extinction.
Autotrophic succession- most
common type in nature; begins in a predominantly inorganic
environment and is characterized by early and continued dominance
of green plants.
Barrier islands - Long, thin,
low, offshore islands of sediment that generally run parallel to
the shore along some coasts.
Biological diversity - variety of
different species (species diversity), genetic variability among
individuals within each species (genetic diversity), and variety
of ecosystems (ecological diversity).
Biome - terrestrial regions
inhabited by certain types of life, especially vegetation.
Examples are various types of deserts, grasslands, and
Bioregion - a unique life-place
with its own soils, landforms, watersheds, climates, native plants
and animals, and many other distinct natural characteristics.
Biotic potential - maximum rate
at which the population of a given species can increase when there
are no limits of any sort on its rate of growth.
Carrying capacity (K) - maximum
population of a particular species that a given habitat can
support over a given period of time.
Clear-cutting - method of timber
harvesting in which all trees in a forested area are removed in a
Coastal wetland - Land along a
coastline, extending inland from an estuary that is covered with
salt water all or part of the year. Examples are marshes, bays,
lagoons, tidal flats, and mangrove swamps.
Competition - two or more
individual organisms of a single species (intraspecific
competition) or two or more individuals of different species
(interspecific competition) attempting to use the same scarce
resources in the same ecosystem.
Consumer - organism that cannot
synthesize the organic nutrients it needs and gets its organic
nutrients by feeding on the tissues of producers or of other
consumers; generally divided into primary consumers (herbivores),
secondary consumers (carnivores), tertiary (higher-level)
consumers, omnivores, and detritivores (decomposers and detritus
Consumption overpopulation -
situation in which people in the world or in a geographic region
use resources at such a high rate and without sufficient pollution
prevention and control that significant pollution, resource
depletion, and environmental degradation occur.
Controlled burning - deliberately
set, carefully controlled surface fires to reduce flammable litter
and decrease the chances of damaging crown fires.
Coral reef - formation produced
by massive colonies containing billions of tiny coral animals,
called polyps, which secrete a stony substance (calcium carbonate)
around themselves for protection. When corals die, their empty
outer skeletons form layers that cause the reef to grow. They are
found in the coastal zones of warm tropical and subtropical
Crown fire - extremely hot forest
fire that burns ground vegetation and tree tops.
Debt-for-nature-swap - agreement
in which a certain amount of foreign debt is cancelled in exchange
for local currency investments that will improve natural resource
management or protect certain areas from harmful development in
the debtor country.
Deforestation - removal of trees
from a forested area without adequate replanting.
Desert - biome where evaporation
exceeds precipitation and the average mount of precipitation is
less than 25 centimeters (10 inches) a year. Such areas have
little vegetation or have widely spaced, mostly low
Desertification - conversion of
rangeland, rain-fed cropland, or irrigated cropland to desertlike
land, with a drop in agricultural productivity of 10% or more. It
is usually caused by a combination of overgrazing, soil erosion,
prolonged drought, and climate change.
Ecological diversity - the
variety of forests, deserts, grasslands, oceans, streams, lakes,
and other biological communities interacting with one another and
with their nonliving environment.
Ecological niche - total way of
life or role of a species in an ecosystem. It includes all
physical, chemical, and biological conditions a species needs to
live and reproduce in an ecosystem.
Ecology - study of the
interactions of living organisms with one another and with their
nonliving environment of matter and energy; study of the structure
and function of nature.
Environmental degradation -
depletion or destruction of a potentially renewable resource such
as soil, grassland, forest, or wildlife by using it at a faster
rate than it is naturally replenished. If such use continues, the
resource can become nonrenewable on a human time scale or
Environmental science - study of
how we and other species interact with each other and with the
nonliving environment of matter and energy. It is a holistic
science that uses and integrates knowledge from physics,
chemistry, biology (especially ecology), geology, geography,
resource technology and engineering, resource conservation and
management, demography (the study of population dynamics),
economics, politics, and ethics.
Estuary - partially enclosed
coastal area at the mouth of a river where its fresh water,
carrying fertile silt and runoff from the land, mixes with salty
Extinction - complete
disappearance of a species from the earth. This happens when a
species cannot adapt and successfully reproduce under new
environmental conditions or when it evolves into one or more new
Food web - complex network of
many interconnected food chains and feeding relationships.
Forest - biome with enough
average annual precipitation (at least 76 centimeters,or 30
inches) to support growth of various species of trees and smaller
forms of vegetation.
Gene pool - the sum total of all
genes found in the individuals of the population of a particular
Grassland - biome found in
regions where moderate annual average precipitation (25 to 76
centimeters, or 10 to 30 inches) is enough to support the growth
of grass and small plants, but not enough to support large stands
Habitat - place or type of place
where an organism or a population of organisms lives.
characterized by early dominance of heterotrophs; occurs in cases
where environment is primarily organic.
Immature community - community at
an early stage of ecological succession. It usually has a low
number of species and ecological niches and cannot capture and use
energy and cycle critical nutrients as efficiently as more
complex, mature ecosystems.
Indicator species - species that
serve as early warnings that a community or an ecosystem is being
Inland wetland - land away from
the coast, such as a swamp, marsh, or bog, that is covered all or
part of the year with fresh water.
Keystone species - species that
play roles affecting many other organisms in an ecosystem.
Limiting factor - single factor
that limits the growth, abundance, or distribution of the
population of a species in an ecosystem.
Mature community - fairly stable,
self-sustaining community in an advanced stage of ecological
succession; usually has a diverse array of species and ecological
niches; captures and uses energy and cycles critical chemicals
more efficiently than simpler, immature communities.
Native species - species that
normally live and thrive in a particular ecosystem.
Natural selection - process by
which a particular beneficial gene or set of genes is reproduced
more than others in a population, through adaptation and
differential reproduction. It is the major mechanism leading to
Old-growth forest - virgin and
old, second-growth forests containing trees that are often
hundreds, sometimes thousands, or years old.
Overpopulation - state in which
there are more people than can live on Earth or in a geographic
region in comfort, happiness, and health and still leave the
planet or region a fit place for future generations. It is a
result of growing numbers of people, growing affluence (resource
consumption), or both.
Pioneer community - first
integrated set of plants, animals, and decomposers found in an
area undergoing primary ecological succession.
Pioneer species - first hardy
species, often microbes, mosses, and lichens, that begin
colonizing a site as the first stage of ecological
Primary succession - sequential
development of communities in a bare area that has never been
occupied by a community of organisms.
Riparian zones - thin strips and
patches of vegetation that surround streams. They are very
important habitats and resources for wildlife.
Secondary succession - sequential
development of communities in an area in which natural vegetation
has been removed or destroyed but the soil is not destroyed.
Successional Theory - Current
theory holds that ecosystem development results from modification
of the physical environment by the biotic community acting as a
whole (the holistic component); the interaction of competition and
coexistence between component populations (the individualistic
component); and a shift in energy flow from production to
respiration as more and more of the available energy is required
to support the increasing organic structure (the community