Primary and Secondary Succession

​4.3 Succession

​I understand how ecosystems change over time

I can describe how ecosystems recover from a disturbance

I can compare succession after a natural disturbance vs a human-caused disturbance​

​Primary and Secondary Succession

​The series of predictable changes that occur in a community over time is called ecological succession. Over the course of succession, the number of different species usually increases.

• ​Primary succession begins in areas with no remnants of an older community. It occurs on bare rock surfaces where no soil exists. The first species to live in an area of primary succession are called pioneer species.

• Secondary succession occurs when a disturbance changes a community without completely destroying it.

Open Ended

Why does ecological succession occur?

​Climax Communities

​A climax community is a mature, relatively stable ecosystem.

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• Secondary succession in healthy ecosystems following natural disturbances often reproduces the original climax community.

• Ecosystems may or may not recover from extensive human-caused disturbances.

Open Ended

What kinds of conditions might prevent a ecological community from returning to its predisturbance state?

Open Ended

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