Succession
• Fire, floods, volcanoes, hurricanes, and other natural disasters can change communities in a short period of time.
• Even without a disaster, communities change.
• Succession– The natural processes by which one community of
organisms slowly replaces another in a certain area.– 2 Types
• Primary• Secondary
Primary Succession
• Primary Succession– The series of changes that occur in an area where no
ecosystem previously existed.
• Steps– Land created by volcanic eruption or retreat of glacier– No soil present– Pioneer Species
• The first organisms to live in an area.• Usually lichens or mosses that grow on rocks• Break up the rocks to form soil.
– Soil development– Seeds of plants land in new soil and begin to grow
• Several hundred-thousand years
Secondary Succession
• Secondary succession– The series of changes that occur after a disturbance in
an existing ecosystem.– Ex. Fires, hurricanes, tornadoes, farming, logging, or
mining.– Occurs in a place where an ecosystem has
previously existed– Occurs more rapidly than primary succession
• Around 100 years
Succession Summary
Succession
Creates new ecosystem
Restores previous
ecosystem
Example:New land created
by volcanic eruption
Example:An area
destroyed by fire
Primary Secondary
Summary Questions
• How are primary and secondary succession different?
• What is a pioneer species?
• Give two examples of natural disturbances and two examples of human disturbances that can result in secondary succession.
• Grass poking through the cracks in a sidewalk is an example of succession. Is this primary or secondary succession? Explain.
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