Chapter 53 Community Ecology

1. Chapter 53 Community Ecology

2. Community Ecology • The study of the interactions between the species in an area.

3. Succession-good link for review • http://www.restoringearth.co.uk/education/science/geography/ecology/succession/succession.shtm

4. chameleons • Almost half of the world’s chameleon species live on the island of Madagascar. • Go to pbs. org • Type in chameleons and find out why they really change color!

5. Community Hypothesis 1. Individualistic 2. Interactive

6. Individualistic Hypothesis • H.A. Gleason • Community as a chance assemblage of species because of similar abiotic requirements.

7. Interactive Hypothesis • F.E. Clements • Community as a linked assemblage of species that function as an integrated whole.

8. Predictions • Individualistic - fuzzy borders • Interactive - sharp borders • Robert Whittaker – tested the two ideas against each other.

10. Results • If abiotic factors form a continuum, then borders are fuzzy. • Individualistic Hypothesis is correct.

11. Comment • Abiotic factors may form sharp borders. • Ex: soil types • Result – the Community may look very much like the Interactive Hypothesis.

12. Interspecific Interactions • Interaction between species. • May be positive, negative, or neutral. • Ex: 1. Coevolution 2. Predation 3. Mimicry 4. Competition 5. Symbiosis

13. When two species have reciprocal evolution to each other. Ex: Flowers and their pollinators. Coevolution

14. Predator and prey relationships. Ex – Lynx and Hares Predation (+/-)

15. Predation • Often results in interesting defenses or adaptations. • Ex: • Plant defenses • Cryptic coloration • Aposematic coloration

16. Cryptic Coloration • A passive defense where the prey is camouflaged against its environment.

17. The use of conspicuous colors in toxic or unpalatable organisms to warn off predators. poison arrow frogs Aposematic Coloration

18. Homework • Reading – Chapters 53, 55 • Chapter 52 - today • Chapter 52 – Fri. 4/25 • Aquatic Productivity – wait until data is posted

19. Mimicry • Defense mechanism where the mimic has a resemblance to another species, the model. • Types: • Batesian • Mullerian

20. Batesian Mimicry • Palatable species mimics an unpalatable model. Hawk moth larva Snake

21. Mullerian Mimicry • Two unpalatable species resemble each other. Yellow Jacket Cuckoo Bee

22. Competition • When two species rely on the same limiting resource. • Intraspecific competition usually more severe than Interspecific competition. • Why?

23. Competitive Exclusion Principle • Predicts that two species with the same requirement can not co-exist in the same community. • One species will survive and the second will go extinct.

24. Ecological Niche • The n-hyperspace of requirements for a species. • How a species “fits into” an ecosystem. • Species can not have niche overlap, the Competitive Exclusion Principle

25. Niche Types • Fundamental - what a species is theoretically capable of using. 2. Realized - what a species can actually use.

27. Resource Partitioning • A way that species avoid niche overlap by splitting up the available resources. • Ex: Anolis lizards

28. A. distichus A. insolitus

30. Symbiosis • When two different species live together in direct contact. • Types: 1. Parasitism 2. Commensalism 3. Mutualism

31. Parasitism (+/-) • Parasite harms the host. • Parasites may be external or internal. • Well adapted parasites don't kill the host.

32. Parasitic behavior: A female Nasonia vitripennis laying a clutch of eggs into the pupa of a blowfly (Phormia regina)

33. One partner benefits while the other is unchanged. Ex. – Cattle and Egrets Commensalism (+/o)

34. Both partners benefit from the interaction. Ex: Pollinators and flowers Mutualism (+/+) Acacia Tree and Ants

35. Changes in species composition over time. Succession

36. Succession Stages • Sere: unstable stage usually replaced by another community. • Climax: stable stage, self-reproducing.

37. Succession Types 1. Primary 2. Secondary

38. Primary Succession • Building a community from a lifeless area. • Ex: volcanic islands glaciated areas road cuts

39. Comment • The first example of primary succession was worked out on the Indiana Dunes. • Stages: • Open Beach • Beach Grasses • Conifers (Junipers and Pines) • Oaks • Beech-Maple forest (Climax)

40. Secondary Succession • Where a community has been disturbed and the soil is mostly intact. • Ex: • Cutting down a forest • Blow-outs on the Dunes

41. Causes of Succession 1. Autogenic Factors 2. Allogenic Factors

42. Autogenic Factors • Changes introduced by the organisms themselves. • Ex: toxins acids

43. Outside disturbances Ex: Fire Floods Allogenic Factors Prairie Restoration Project Upland, IN

44. Biogeography • Study of the past and present distributions of individual species and communities.

45. Range Limitations 1. Lack of dispersion. 2. Failure to survive in new areas. 3. Retraction from former range area.

46. Proof • Fossil Evidence • Pollen Studies • Transplant Experiments

47. Islands • Special cases in Biogeography. • Must be colonized from other areas.

48. Island Species Factors • Island size. • Distance from mainland.