1 Mon. Tues. Wed. Thurs. Fri. Week of Nov. 10 Independent project analysis Week of Nov. 17 River ecology lab – dress for weather Lab Exam T lab switch? Week of Nov. 24 No lab – Thanksgiving No lecture Week of Dec. 1 Independent project presentations

2 Structure of course Environmental variability Organisms Ecosystems Populations Species interactions Communities Applied Ecological Issues

3 Consumer/resource interactions 1.Predation 2.Herbivory 3.Parasitism 4.Dynamics of C/R interactions

4 Why don’t herbivores drive plants extinct? Or Why is the world green? 1.Plant defense - physical - chemical 2. Plants can hide too 3. Herbivores have predators

5 Constitutive defense

6 Figure Induced defense

7 Why don’t herbivores drive plants extinct? Or Why is the world green? 1.Plant defense 2.Plants can hide too 3.Herbivores have predators

8 Figure 17.1 Spatial refuge

9 Index of cone production Production of population not individuals Cost

10 Why don’t herbivores drive plants extinct? Or Why is the world green? 1.Plant defense 2.Plants can hide too 3.Herbivores have predators

11 Predator Herbivore Algae

12 Consumer/resource interactions 1.Predation 2.Herbivory 3.Parasitism 4.Dynamics of C/R interactions

13 How is a parasite different from a predator?

14 Parasites are incredibly diverse Examples?

15

16 Challenges for a parasite

17 Figure 17.14

18 tapeworm in a crow pillbug = intermediate host tapeworm changes pillbug behavior

19 Consumer/resource interactions 1.Predation 2.Herbivory 3.Parasitism 4.Dynamics of C/R interactions

20 Dynamics of consumer/resource interactions Consumers can reduce resource populations Examples of cycles Models of consumer/resource interactions

21 Figure Effect on growth rate

22

23 Dynamics of consumer/resource interactions Consumers can reduce resource populations Examples of cycles Models of consumer/resource interactions

24 Figure 18.4 size of measles population Cause of cycle?

25 Figure 18.2

26 Lynx Hare + -

27 Dynamics of consumer/resource interactions Consumers can reduce resource populations Examples of cycles Models of consumer/resource interactions - math helps understand mechanisms

28 For prey (R): dR/dt = rR – predation For predators (P): dP/dt = rate at which prey are converted to new predators – death of predators

29 Species interactions Introduction Consumer/resources interactions (predation, herbivory, parasitism) Competition Mutualism

30 Interspecific Competition Introduction Competitive exclusion How do species coexist?

Competitive interactions AB

32 What are some resources that organisms compete for?

33 Intraspecific competition – competition between individuals of the same species Interspecific competition – competition between individuals of different species

34 Two methods of competition Interference competition Exploitation competition

35 Figure Exploitation Interference

36 Interspecific exploitation competition Intraspecific exploitation competition Intraspecific interference competition

Competition may be asymmetric AB

38 Figure A B

39 AB Species A has a bigger effect on B than B has on A How would you draw this?

40 Which one of the following is not an example of competition between species? a. Blowflies and fleshflies breed in the same types of carcasses, and both species experience reduced reproduction rates when densities within carcasses are high. b. Sage plants produce a ring of bare ground surrounding them. c. Wolverines and mountain lions fight each other for deer carcasses. d. Spotted owls and great horned owls occupy the same type of habitat.

41 Competition Introduction Competitive exclusion How do species coexist?

42 Figure 19.6

43 Figure 19.2

44 Competitive exclusion principle: two species that use the same limiting resource in the same way cannot coexist Limiting resource – a resource which is scarce relative to the demand for it

45 Competitive exclusion is difficult to witness outside of laboratory experiments Why??

46 Figure parasitoids – all use resource same way

47 Competition Introduction Competitive exclusion How do species coexist?

48 How do species coexist? 1.Resource partitioning 2.Predation on one or more species

49 How do species coexist? 1.Resource partitioning -different species aren’t using the same resource exactly the same way

50 Eats small to medium seeds Eats medium to big seeds

warbler species all eat insects in spruce trees

52 How do species coexist? 2. Predation on one or more species

AB

AB Consumer - +

55 Mussel = dominant competitor Bob Paine experiments