1. Competition

2. Coastal sage scrub – note bare spots near shrubs

3. Rabbit grazing – source of apparent competition

4. Species Coexistence Serengeti National Park

5. Species Coexistence Competition is a common feature of species interactions, yet often we find very similar species coexisting in nature, species that seem to need the same resources. How do they coexist? Refuge from competition Predation keeps populations of each species low enough that they do not compete Resources may be variable in space and time, so that the species coexist because both do not find resource at same time

6. Dung – a valuable, variable resource Dung Beetles Dung Fly

7. Predation Great White Shark and Fur Seal

9. Lions hunting – True Predator

10. Moose Browsing – Partial Predator

11. Parasitoid Wasp

12. Specialists and Generalist Predators Advantages to being a specialist 1. Avoid interspecific competition 2. Allows evolution to overcome chemical defense 3. Allows evolution of cryptic coloration that matches prey - mostly for insects on plants 4. Increases chance of mate encounter Advantages of being a generalist 1. Flexibility in face of environmental uncertainty 2. Broad diet needed to get all necessary nutrients and vitamins 3. Avoid overdosing on any one toxin - mostly for animals grazing on chemically defended plants

14. Pied Wagtail

16. Caribou eating lichens

17. Edible mussel – Mytilus edulis

20. Black oystercatcher

21. Bluegill sunfish

23. Mink Muskrat

25. Red grouse in heather

26. Tawny Owl Bank vole

28. Cinnabar Moth and Caterpillar on Ragwort Tansy

29. Snowshoe hare and Lynx

32. Lynx Ruffed GrouseSnowshoe hare

33. Sea Otter

34. Sea Urchin

35. Kelp Forest

36. Sea Otter eating Sea Urchin in Kelp Forest

37. Comparison of kelp and urchin biomass with and without sea otters

38. Kelp forest ecsystems with and without sea otters