1. End Show 4-2 What Shapes an Ecosystem? Slide 1 of 39 Copyright Pearson Prentice Hall Community Interactions What interactions occur within communities?

2. End Show 4-2 What Shapes an Ecosystem? Slide 2 of 39 Copyright Pearson Prentice Hall Community Interactions Competition Competition occurs when organisms of the same or different species attempt to use an ecological resource in the same place at the same time. A resource is any necessity of life, such as water, nutrients, light, food, or space.

3. End Show 4-2 What Shapes an Ecosystem? Slide 3 of 39 Copyright Pearson Prentice Hall Community Interactions Direct competition in nature often results in a winner and a loser—with the losing organism failing to survive. The competitive exclusion principle states that no two species can occupy the same niche in the same habitat at the same time.

4. End Show 4-2 What Shapes an Ecosystem? Slide 4 of 39 Copyright Pearson Prentice Hall Community Interactions The distribution of these warblers avoids direct competition, because each species feeds in a different part of the tree. Yellow-Rumped Warbler Bay-Breasted Warbler Feeding height (m) 0 6 12 18 Cape May Warbler

5. End Show 4-2 What Shapes an Ecosystem? Slide 5 of 39 Copyright Pearson Prentice Hall Community Interactions Predation An interaction in which one organism captures and feeds on another organism is called predation. The organism that does the killing and eating is called the predator, and the food organism is the prey.

6. End Show 4-2 What Shapes an Ecosystem? Slide 6 of 39 Copyright Pearson Prentice Hall Community Interactions Symbiosis Any relationship in which two species live closely together is called symbiosis. Symbiotic relationships include: mutualism commensalism parasitism

7. End Show 4-2 What Shapes an Ecosystem? Slide 7 of 39 Copyright Pearson Prentice Hall Community Interactions Mutualism: both species benefit from the relationship. Commensalism: one member of the association benefits and the other is neither helped nor harmed. Parasitism: one organism lives on or inside another organism and harms it.

8. End Show 4-2 What Shapes an Ecosystem? Slide 8 of 39 Copyright Pearson Prentice Hall Ecological Succession What is ecological succession?

9. End Show 4-2 What Shapes an Ecosystem? Slide 9 of 39 Copyright Pearson Prentice Hall Ecological Succession This series of predictable changes that occurs in a community over time is called ecological succession. Sometimes, an ecosystem changes in response to an abrupt disturbance. At other times, change occurs as a more gradual response to natural fluctuations in the environment.

10. End Show 4-2 What Shapes an Ecosystem? Slide 10 of 39 Copyright Pearson Prentice Hall Ecological Succession Primary Succession When organisms inhabit an area for the first time. No soil Occurs when: 1. Volcanic Rock hardens 2. Glacier Melts and exposes new rock

11. End Show 4-2 What Shapes an Ecosystem? Slide 11 of 39 Copyright Pearson Prentice Hall Ecological Succession In this example, a volcanic eruption has destroyed the previous ecosystem.

12. End Show 4-2 What Shapes an Ecosystem? Slide 12 of 39 Copyright Pearson Prentice Hall Ecological Succession The first organisms (Pioneer Species) to appear are lichens.

13. End Show 4-2 What Shapes an Ecosystem? Slide 13 of 39 Copyright Pearson Prentice Hall Ecological Succession Mosses soon appear, and grasses take root in the thin layer of soil.

14. End Show 4-2 What Shapes an Ecosystem? Slide 14 of 39 Copyright Pearson Prentice Hall Ecological Succession Eventually, tree seedlings and shrubs sprout among the plant community.

15. End Show 4-2 What Shapes an Ecosystem? Slide 15 of 39 Copyright Pearson Prentice Hall Ecological Succession Secondary Succession Components of an ecosystem can be changed by natural events or human disturbances. When the disturbance is over, community interactions tend to restore the ecosystem to its original condition through secondary succession.

16. End Show 4-2 What Shapes an Ecosystem? Slide 16 of 39 Primary succession (1000s of years) is a much longer process than secondary succession(100s of years) because primary has no soil or seeds to start. Copyright Pearson Prentice Hall

17. End Show - or - Continue to: Click to Launch: Slide 17 of 39 Copyright Pearson Prentice Hall 4-2

18. End Show Slide 18 of 39 Copyright Pearson Prentice Hall 4-2 Which of the following is a biotic factor in a bullfrog's niche? a.water b.a heron c.climate d.day length

19. End Show Slide 19 of 39 An organism’s niche is different from its habitat because a.The niche does not include the place where the organism lives. b.the niche includes all the conditions under which the organism lives. c.the niche includes only abiotic factors. d.the niche includes only biotic factors. Copyright Pearson Prentice Hall 4-2

20. End Show Slide 20 of 39 Copyright Pearson Prentice Hall 4-2 The attempt by organisms of the same or different species to use a resource at the same time in the same place is called a.competition. b.predation. c.symbiosis. d.cooperation.

21. End Show Slide 21 of 39 Copyright Pearson Prentice Hall 4-2 An association between two species in which one species benefits and the other is neither helped nor harmed is called a.symbiosis. b.mutualism. c.commensalism. d.parasitism.

22. End Show Slide 22 of 39 Copyright Pearson Prentice Hall 4-2 When a volcano erupts and completely destroys an ecosystem, the first species to populate the area are usually a.grasses and shrubs. b.pioneers such as lichens. c.small plants such as mosses. d.small animals such as rodents.

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