1. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh Edition Solomon Berg Martin Chapter 52 Community Ecology

2. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 52 Community Ecology Ecological niche Distinctive lifestyle and role of an organism in a community Takes into account all abiotic and biotic aspects For example, an organism’s habitat is one parameter used to describe the niche

3. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 52 Community Ecology Connections to the size of the acorn crop

4. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 52 Community Ecology Fundamental niche Potential ecological niche for an organism Realized niche Niche an organism actually occupies Limiting resources Environmental factors that restrict a realized niche

5. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 52 Community Ecology Effect of competition on an organism’s realized niche

6. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 52 Community Ecology Competition Two or more individuals attempting to use the same resource Intraspecific competition –Among individuals within a population Interspecific competition –Between different species

7. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 52 Community Ecology Interspecific competition

8. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 52 Community Ecology Competitive exclusion principle Two species cannot occupy the same niche in the same community for an indefinite period One species is excluded by another as a result of competition

9. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 52 Community Ecology Some species reduce competition by resource partitioning Competition among species is reduced by character displacement Structural ecological and behavioral characteristics diverge where ranges overlap

10. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 52 Community Ecology Resource partitioning

11. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 52 Community Ecology Predation Consumption of one species (the prey) by another (the predator) Coevolution Predator and prey both evolve more efficient ways to interact

12. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 52 Community Ecology Ecological interactions among species

13. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 52 Community Ecology Defenses Mechanical defenses Associating in groups Cryptic coloration Warning coloration Müllerian mimicry

14. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 52 Community Ecology Cryptic coloration

15. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 52 Community Ecology Symbiosis Mutualism –Both partners benefit Commensalism –One partner benefits and the other is unaffected Parasitism –One partner benefits while the other is harmed

16. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 52 Community Ecology Mutualism

17. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 52 Community Ecology Commensalism

18. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 52 Community Ecology Parasitism

19. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 52 Community Ecology Keynote species Present in small numbers but are crucial in determining the species composition and ecosystem functioning Dominant species Affect the community because they are so common

20. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 52 Community Ecology Species richness Number of species within a community Species diversity Relative importance of each species within a community

21. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 52 Community Ecology Effect of community complexity on species richness

22. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 52 Community Ecology Ecological succession Primary succession –Occurs in an area not previously inhabited Secondary succession –Occurs where there is a pre-existing community and well-formed soil

23. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 52 Community Ecology Intermediate disturbance hypothesis Disturbance affects succession and species richness Species richness is greatest at moderate levels of disturbance

24. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 52 Community Ecology Intermediate disturbance hypothesis

25. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 52 Community Ecology The nature of communities Organismic model –Views a community as a superorganism that goes through stages of development (succession) Individualistic model –Abiotic environmental factors are primary determinants of species composition –Organisms are independent