1. Community Ecology

2. Species Interactions the effects of one species on another may be negative, positive, or neutral five kinds of interactions: POPULATION APOPULATION B COMPETITION PREDATION PARASITISM COMMENSALISM MUTUALISM

3. Intraspecific Competition Intraspecific Competition – members of the SAME species compete for resources

4. Interspecific Competition Interspecific Competition – two or more DIFFERENT species use the same limited resource (food, space, etc.) and adversely affect each other – / – niche overlap Ex: fire ants & native ants in North America

5. High Low Relative population density 024681012141618 Days Each species grown alone Paramecium aurelia Paramecium caudatum No Competition

6. High Low Relative population density 024681012141618 Days Both species grown together Paramecium aurelia Paramecium caudatum Interspecific Competition

8. Resource Partitioning Species with similar resource requirements can coexist because they use limited resources: at different times in different ways in different places © Brooks/Cole Publishing Company / ITP

9. Resource Partitioning

10. Competitive exclusion principle - no two species can occupy the same niche at the same time Dividing resources can be a “truce” in the competition for resources

11. Parasitism One organism (parasite) lives in or on part of another organism (host) + / – Ex: flea living on a dog © Brooks/Cole Publishing Company / ITP

12. Mutualism Two species interact in a way that benefits both + / + Ex: lichens (algae & fungi) Ex: clownfish & anemones Ex: ants & acacias © Brooks/Cole Publishing Company / ITP

13. Commensalism One organism benefits from another, but neither helps nor harms the other organism + / 0 Ex: elephants and cattle egrets

15. Keystone Species Keystone Species: species that play a critical role in an ecosystem Ex: sea otters are keystone species because they prevent sea urchins from depleting kelp beds Ex: flying foxes are keystone species because they pollinate & disperse tropical trees such as durian

16. Keystone Species Increase Biodiversity

17. Primary Succession Primary succession – occurs on surfaces that are initially devoid of soil

18. Pioneer Species – Lichens and Moss

19. Secondary Succession Secondary succession – occurs in areas that have been disturbed, but have not lost their soil

20. http://www.youtube.com/watch?v=1m3a4fdSipw

21. 1988 2001

22. 1988 2001

23. The Secondary Succession Cycle