Vocabulary Review
Ch 18
Ecology
The study of the
interactions between
organisms and the other
living and nonliving
components of their
environment
Ecology
The dependence of
every organism on its
connections with other
living and nonliving parts
of its environment
Interdependence
A model that
represents or describes
the relationships
between the components
of an ecological system
Ecological model
The part of the
Earth where life
exists; includes all of
the living organisms
on Earth
Biosphere
A community of
organisms and their
abiotic environment
Ecosystem
A group of various
species that live in
the same habitat and
interact with each
other
Community
A group of organisms
of the same species
that live in a specific
geographical area and
interbreed
Population
The place where an
organism usually lives
Habitat
An environmental factor
that is associated with
or results from the
activities of living
organisms
Biotic factor
An environmental
factor that is not
associated with the
activities of living
organisms
Abiotic factor
A graph of the
performance of an
organism versus the
value of an
environmental variable
Tolerance curve
An organism’s change
in response to a
change in the
organism’s
environment
Acclimation
A state in which seeds,
spores, bulbs, and other
reproductive organs stop
growth and development
and reduce their
metabolism, especially
respiration
Dormancy
In general, any movement of
individuals or populations from
one location to another;
specifically, a periodic group
movement that is
characteristic of a given
population or species
Migration
The unique position
occupied by a species,
both in terms of its
physical use of its habitat
and its function within an
ecological community
Niche
An organism that can make
organic molecules from
inorganic molecules; a
photosynthetic or
chemosynthetic autotroph
that serves as the basic food
source in an ecosystem
Producer
The production of
carbohydrates
through the use of
energy from inorganic
molecules instead of
light
Chemosynthesis
The rate at which
organic matter is
assimilated by plants
and other producers
during a period of time
over a certain area
Gross primary
productivity
Any organic material
that has been
produced in an
ecosystem
Biomass
The rate at which
biomass accumulates
in an ecosystem
Net primary
productivity
An organism that eats
other organisms or organic
matter instead of
producing its own nutrients
or obtaining nutrients from
inorganic sources
Consumer
An organism that
eats only plants
Herbivore
An organism that
eats animals
Carnivore
An organism that
eats a variety of
other organisms,
including animals and
plants
Omnivore
A consumer that
feeds on dead
organisms or on the
parts of wastes of
other organisms
Detritivore
An organism that
feeds by breaking
down organic matter
from dead organisms;
examples include
bacteria and fungi
Decomposer
An organism’s relative position
in a sequence of energy
transfers in a food chain or
food pyramid, examples
include producers and
primary, secondary, and
teriary consumers
Trophic level
The pathway of energy
transfer through
various stages as a
result of the feeding
patterns of a series of
organisms
Food chain
A diagram that shows
the feeding
relationships among
organisms in an
ecosystem
Food web
Cycle the circulation
of substances through
living organisms from
or to the environment
Biogeochemical
cycle
The water that is
beneath the Earth’s
surface
Groundwater
The continuous
movement of water
between the
atmosphere, the land,
and the oceans
Water Cycle
The process by which
plants release water vapor
into the air through
stomata; also, the release
of water vapor into the air
by other organisms
Transpiration
The movement of
carbon from the
nonliving environment
into living things and
back
Carbon cycle
The process in which
nitrogen circulates
among the air, soil,
water, plants, and
animals in an
ecosystem
Nitrogen cycle
The process by which
gaseous nitrogen is
converted into nitrates,
compounds that organisms
can use to make amino
acids and other nitrogencontaining organic
molecules
Nitrogen fixation
A bacterium that
converts atmospheric
nitrogen into ammonia
Nitrogen-fixing
bacteria
The formation of
ammonia compounds in
the soil by the action
of bacteria on
decaying matter
Ammonification
The process by which
nitrites and nitrates
are produced by
bacteria in the soil
Nitrification
The liberation of
nitrogen from
nitrogen-containing
compounds by
bacteria in the soil
Denitrification
The cyclic movement of
phosphorus in different
chemical forms from the
environment to organisms
and then back to the
environment
Phosphorus cycle