Changes in Ecosystems: Ecological Succession

1. Changes in Ecosystems:Ecological Succession 1.5

2. Changes by Fire • Naturally occurring catastrophic events can change the planet we live on. Earth is constantly changing. • Sometimes these changes take millions of years, but sometimes they happen in just minutes…

4. MOST DEADLY AND DESTRUCTIVE VOLCANO IN THE UNITED STATES: MOUNT ST. HELENS

5. Definition of Succession • Natural, gradual changes in the types of species that live in an area • The gradual replacement of one plant/animal community by another through natural processes over time • Can be primary or secondary

6. Primary Succession • Begins in a place without any soil • Sides of volcanoes • Land uncovered by retreating glacier • After flooding when soil was washed away • Starts with the arrival of living things such as lichens that do not need soil to survive • Called PIONEER SPECIES

7. Lichen: A combination of algae and fungus that can survive on bare rock, tree bark, and other surfaces. Lichen is a “pioneer species”

8. Other early species include mosses and ferns. They begin the breakdown of rocks into soil These rocks are slowly becoming the soil!

9. 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 tiny amounts of soil

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

12. Primary Succession • The simple plants die, adding more organic material • The soil layer thickens, and grasses, wildflowers, and other plants begin to take over

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

14. Primary Succession • Insects, small birds, and mammals have begun to move in • What was once bare rock now supports a variety of life I’m cute!

15. Primary Succession: Starts on Bare Rock! No SOIL yet.

16. Secondary Succession • Begins in a place that already has soil & was once the home of living organisms • Occurs faster than primary succession • Examples • after forest fires • after agriculture/cultivation

17. Secondary Succession: Soil already in place

18. Climax Community • A stable group of plants and animals that is the end result of the successionprocess • AFTER SUCCESSION THE POPULATION AND NUMBER OF SPECIES INCREASES!! • Nature is all about a balance (equilibrium).

19. Today’s Reading/Questions • 1. What is ecological succession? • A. The gradual change of an ecosystem over time; the gradual change of the types of species that live in an area

20. Today’s Reading/Questions • 2. Explain the difference between primary and secondary succession. • A. Primary succession begins on bare rock/rocky surface with no existing soil, plants, etc. (“new” land)Secondary succession begins with soil already in place (nature takes over)

21. Ecological Succession Create a Venn Diagram comparing primary and secondary succession and underneath write a Notes Summary! Summary of the notes and information learned