1. How do ecosystems change?
C22L3 Quiz

2. How Ecosystems Change
How do land ecosystems change over time?
How do aquatic ecosystems change over time?

3. How Land Ecosystems Change
Ecological succession is the process of one ecological community gradually changing into another.
The final stage of ecological succession in a land ecosystem is a climax community – a stable community that no longer goes through major ecological changes.

4. Ecological succession

5. How Land Ecosystems Change (cont.)
In a tropical forest biome, a mature tropical forest is a climax community.
Climax communities are usually stable for hundreds of years.

6. How Land Ecosystems Change (cont.)
Ecological succession in new areas of land with little or no soil, such as a lava flow or sand dune, is primary succession.
The first species that colonize new or undisturbed land are pioneer species.

9. How Land Ecosystems Change (cont.)
In areas where existing ecosystems have been disturbed or destroyed, secondary succession can occur.

11. Ecological Succession

12. How Freshwater Ecosystems Change
Freshwater ecosystems change over time in a natural, predictable process called aquatic succession.
In aquatic succession the buildup of decomposed remains accumulate over time as soil.
Eventually the water disappears and the area becomes land.

14. How Freshwater Ecosystems Change (cont.)
Eutrophication is the process of a body of water becoming nutrient-rich.

15. Eutrophication

16. How Freshwater Ecosystems Change (cont.)
Eutrophication is a natural process, but humans contribute to it by introducing fertilizer, waste, and other nutrient-rich pollution to a body of water.
High nutrient levels support large populations of algae and other microscopic organisms that end up using most of the dissolved oxygen in the water, leaving less available for fish and other organisms.

17. Succession Song – Mr. Parr