Like many complex systems, ecosystems tend to have cyclic fluctuations
around a state of rough equilibrium. In the long run, however, ecosystems
always change when climate changes or when one or more new species appear
as a result of migration or local evolution.
NSES Content Standard C
Life Science: The interdependence of organisms Grades 9-12, page 186 Organisms both cooperate and compete in ecosystems. The interrelationships and interdependencies of these organisms may generate ecosystems that are stable for hundreds or thousands of years. No closely related standards have been identified.
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