1. 21.4 Changes in communities, page 731
Key Concepts: How do primary and secondary succession differ?
Key terms: succession, primary succession, pioneer species, secondary succession

2. Succession
A series of predictable changes that occur in a community over time

3. Primary succession
Primary succession is the series of changes that occur in an area where no soil or organisms exist
Like a new island recently formed or a rock uncovered recently by ice
Pioneer species – the first species to populate an area
Usually mosses or lichens (fungi and algae growing in a symbiotic relationship)
Break up the rocks, then die and enrich the soil
Then plants come in and grow

4. Secondary succession
A series of changes that occur in an area where the ecosystem has been disturbed, but where soil and organisms still exist
Fires, hurricanes, tornadoes
Farming, logging, mining
Occurs where an ecosystem already exists
Occurs more rapidly than primary.

5. Please complete
Assessment section 4 pg 733
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