Succession 4.3Respond to questions in red.

Key Questions

1. How do communities change over time?2. Do ecosystems return to normal following a

disturbance?

Ecological Succession

• An observable, predictable change in species and community structure over time.

Two types of succession

• Primary succession begins in an area that has no existing community.

• The first species to colonize are the pioneer species.

Two types of succession

• Secondary succession happens when an existing community is destroyed or disturbed by a natural or man-made disaster.

• Examples fire, hurricane, clear cut logging.• This process occurs faster in secondary

succession than in primary succession.

Climax communities

• The end product of succession is usually a specific and stable community called a climax community.

• What happens to the number of species as succession progresses towards the climax community?

Why does the process of succession occur?

• The Earth is a dynamic, ever changing landscape.

• As change occurs, opportunities for new species present themselves.

• What process between species allows certain species to be more successful?

• Why are the “winners” more successful?

Ecosystem recovery

• Healthy ecosystems often respond by replacing the original community after a natural disturbance.

• Human disturbance may be too great for this process to take place.

Looks and sounds like

• Secondary succession• What is the difference between primary and

secondary succession? Give examples of each.