Chapter 43
Self-Quiz
Unit 6: Interaction with the Environment
Communities of Organisms
Review
Communities
are composed of
of different species in a particular environment.
The feeding relationships of who eats whom in a
community
form the
food
, which comprises a
pyramid,
where
energy
is lost in the form of
at each level.
Primary consumers (herbivores) feed on
, while higher-level consumers feed on
consumers. A
cricket
is an example of a
consumer in the trophic pyramid.
Frequently, there is one
species that helps maintain
balance
within the community. An
example
is the
which helps maintain the population of
in an
intertidal
community.
The species composition in a community can change over time in a process called
.
New
habitats experience
succession, in which species
colonize
new territory.
Disturbed
habitats
experience
succession, in which both new and previous inhabitants recolonize the area. Few communities complete succession to form a
community.
Human activity such as
logging,
pollution,
and
by
livestock
can have long-lasting effects on the community and may even cause the
extinction
of some
species.
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