1. Changes in Ecosystems: Ecological Succession

2. What is Ecological Succession?
Natural, gradual changes in the types of species that live in an area
Can be primary or secondary
The gradual replacement of one plant community by another through natural processes over time

3. Primary Succession Begins in a place without any soil:
Sides of volcanoes
Landslides
Flooding
First, lichens that do not need soil to survive grow on rocks
Next, mosses grow to hold newly made soil
Known as PIONEER SPECIES

4. Pioneer Species
Low growing moss plants trap moisture and prevent soil erosion.
Lichens break down rock to form soil.

5. Primary Succession
Soil starts to form as lichens and the forces of weather and erosion help break down rocks into smaller pieces
When lichens die, they decompose, adding small amounts of organic matter to the rock to make soil

7. Primary Succession
Simple plants like mosses and ferns can grow in the new soil

8. Primary Succession
The simple plants die, adding more organic material (nutrients to the soil)
The soil layer thickens, and grasses, wildflowers, and other plants begin to take over.

9. Primary Succession
These plants die and they add more nutrients to the soil.
Shrubs and trees can survive now.

10. Primary Succession
Insects, small birds, and mammals have begun to move into the area.
What was once bare rock, now supports a variety of life.

11. Secondary Succession
Begins in a place that already has soil and was once the home of living organisms
Occurs faster and has different pioneer species than primary succession
Example: after forest fires

12. Ecological Succession
Stages of Secondary Succession

13. Stages of Secondary Succession
Annual plants (weeds)
Annual and perennial plants and weeds
Shrubs
Young pine
forest
5. Mature pine

16. Ecological Succession
Old-field succession is a type of secondary succession that occurs when farmland is abandoned.
When a farmer stops cultivating a field, grasses and weeds quickly grow and cover the abandoned land.
Over time, taller plants, such as perennial grasses, shrubs, and trees take over the area.

17. Climax Community
A stable group of plants and animals that is the end result of the succession process
Does not always mean big trees
Grasses in prairies
Cacti in deserts

18. Write the term or phrase that matches the description
Write the term or phrase that matches the description. Write the statement and the answer. Circle or highlight your answer
a common type of succession that occurs on a surface where an ecosystem has previously existed
2. the first organisms to colonize any newly available area and begin the process of ecological succession
3. a final and stable community
4. a type of succession that occurs on a surface where no ecosystem existed before
5. a type of succession that occurs on abandoned farmland
6. a gradual process of change and replacement of the types of species in a community