1. Community Interactions

2. Community All the populations that live together in a habitat Habitat is the type of place where individuals of a species typically live Type of habitat shapes a community’s structure

3. Factors Shaping Community Structure Climate and topography Available foods and resources Adaptations of species in community Species interactions Arrival and disappearance of species Physical disturbances

4. Niche Sum of activities and relationships in which a species engages to secure and use resources necessary for survival and reproduction

5. Species Interactions Most interactions are neutral; have no effect on either species Commensalism helps one species and has no effect on the other Mutualism helps both species

6. Species Interactions Interspecific competition has a negative effect on both species Predation and parasitism both benefit one species at a cost to another

7. Symbiosis Living together for at least some part of the life cycle Commensalism, mutualism, and parasitism are forms of symbiosis

8. Mutualism Both species benefit Many examples in nature Some mutualisms are obligatory; partners depend upon each other

10. Yucca and Yucca Moth Example of an obligatory mutualism Each species of yucca is pollinated only by one species of moth Moth larvae can grow only in that one species of yucca

11. Mycorrhizae Obligatory mutualism between fungus and plant root Fungus supplies mineral ions to root Root supplies sugars to fungus

13. Improved water and mineral uptake in mycorrhizal plants.

15. Commensalism One species benefits other is not harmed Many examples in nature

19. Periwinkle on Seaweed (worksheet study)

20. Competition Interspecific – between different species Intraspecific - between members of the same species Intraspecific competition is most intense

21. Forms of Competition Competitors may have equal access to a resource; compete to exploit resource more effectively One competitor may be able to control access to a resource, to exclude others

22. Competitive Exclusion Principle When two species compete for identical resources, one will be more successful and will eventually eliminate the other

23. Paramecium caudatum Paramecium aurelia

24. Competitive Exclusion Expt Paramecium caudatum Paramecium aurelia

25. Predation Predators are animals that feed on other living organisms Predators are free-living; they do not take up residence on their prey

26. Coevolution Natural selection promotes traits that help prey escape predation It also promotes traits that make predators more successful at capturing prey

27. Prey Defenses Camouflage Warning coloration Mimicry Moment-of-truth defenses

28. Predator Responses Any adaptation that protects prey may select for predators that can overcome that adaptation Prey adaptations include stealth, camouflage, and ways to avoid chemical repellents

29. Parasitism Parasites drain nutrients from their hosts and live on or in their bodies Natural selection favors parasites that do not kill their host too quickly

30. Types of Parasites Microparasites Macroparasites Social parasites Parasitoids

33. Hog Sphinx Moth caterpillar, seen here on Smartweed, has been parasitized by Cotesia congregata, a braconid that lays its eggs in the caterpillar

34. Cobweb Spider (plus Ichneumonid wasp parasite)

35. Balanophora fungosa produces no chlorophyll so it is unable to manufacture its own food from sunlight so it lives parasitically on the roots of certain plants.

36. Immature Spined Assassin bug with what looks like tachinid egg parasites.

37. Hyalophora cecropia caterpillar

38. Tarantula Hawk Wasp

39. Tarantula Hawk Wasp in action!