Species Interactions and Population Control in Biodiversity

1. Chapter 5 Biodiversity, Species Interactions, and Population Control

2. Core Case Study: Southern Sea Otters: Are They Back from the Brink of Extinction? • Habitat • Hunted: early 1900s • Partial recovery • Why care about sea otters? • Ethics • Tourism dollars • Keystone species

3. Southern Sea Otter Fig. 5-1a, p. 104

4. 5-1 How Do Species Interact? • Concept 5-1 Five types of species interactions—competition, predation, parasitism, mutualism, and commensalism—affect the resource use and population sizes of the species in an ecosystem.

5. Species Interact in Five Major Ways • Interspecific Competition • Predation • Parasitism • Mutualism • Commensalism

6. Most Species Compete with One Another for Certain Resources • For limited resources • Ecological niche for exploiting resources • Some niches overlap

7. Some Species Evolve Ways to Share Resources • Resource partitioning • Using only parts of resource • Using at different times • Using in different ways

8. Resource Partitioning Among Warblers Fig. 5-2, p. 106

9. Blackburnian Warbler Black-throated Green Warbler Cape May Warbler Bay-breasted Warbler Yellow-rumped Warbler Stepped Art Fig. 5-2, p. 106

10. Specialist Species of Honeycreepers Fig. 5-3, p. 107

11. Most Consumer Species Feed on Live Organisms of Other Species (1) • Predators may capture prey by • Walking • Swimming • Flying • Pursuit and ambush • Camouflage • Chemical warfare

12. Predator-Prey Relationships Fig. 5-4, p. 107

13. Most Consumer Species Feed on Live Organisms of Other Species (2) • Prey may avoid capture by • Run, swim, fly • Protection: shells, bark, thorns • Camouflage • Chemical warfare • Warning coloration • Mimicry • Deceptive looks • Deceptive behavior

14. Some Ways Prey Species Avoid Their Predators Fig. 5-5, p. 109

15. (a) Span worm (b) Wandering leaf insect (c) Bombardier beetle (d) Foul-tasting monarch butterfly (f) Viceroy butterfly mimics monarch butterfly (e) Poison dart frog (g) Hind wings of Io moth resemble eyes of a much larger animal. (h) When touched, snake caterpillar changes shape to look like head of snake. Stepped Art Fig. 5-5, p. 109

16. Science Focus: Threats to Kelp Forests • Kelp forests: biologically diverse marine habitat • Major threats to kelp forests • Sea urchins • Pollution from water run-off • Global warming

17. Purple Sea Urchin Fig. 5-A, p. 108

18. Predator and Prey Interactions Can Drive Each Other’s Evolution • Intense natural selection pressures between predator and prey populations • Coevolution • Interact over a long period of time • Bats and moths: echolocation of bats and sensitive hearing of moths

19. Coevolution: A Langohrfledermaus Bat Hunting a Moth Fig. 5-6, p. 110

20. Some Species Feed off Other Species by Living on or in Them • Parasitism • Parasite is usually much smaller than the host • Parasite rarely kills the host • Parasite-host interaction may lead to coevolution

21. Parasitism: Trout with Blood-Sucking Sea Lamprey Fig. 5-7, p. 110

22. In Some Interactions, Both Species Benefit • Mutualism • Nutrition and protection relationship • Gut inhabitant mutualism • Not cooperation: it’s mutual exploitation

23. Mutualism: Hummingbird and Flower Fig. 5-8, p. 110

24. Mutualism: Oxpeckers Clean Rhinoceros; Anemones Protect and Feed Clownfish Fig. 5-9, p. 111

25. (a) Oxpeckers and black rhinoceros Fig. 5-9a, p. 111

26. (b) Clownfish and sea anemone Fig. 5-9b, p. 111

27. In Some Interactions, One Species Benefits and the Other Is Not Harmed • Commensalism • Epiphytes • Birds nesting in trees

28. Commensalism: Bromiliad Roots on Tree Trunk Without Harming Tree Fig. 5-10, p. 111

29. 5-2 What Limits the Growth of Populations? • Concept 5-2 No population can continue to grow indefinitely because of limitations on resources and because of competition among species for those resources.

30. Most Populations Live Together in Clumps or Patches (1) • Population: group of interbreeding individuals of the same species • Population distribution • Clumping • Uniform dispersion • Random dispersion

31. Most Populations Live Together in Clumps or Patches (2) • Why clumping? • Species tend to cluster where resources are available • Groups have a better chance of finding clumped resources • Protects some animals from predators • Packs allow some to get prey

32. Population of Snow Geese Fig. 5-11, p. 112

33. Generalized Dispersion Patterns Fig. 5-12, p. 112

34. Populations Can Grow, Shrink, or Remain Stable (1) • Population size governed by • Births • Deaths • Immigration • Emigration • Population change = (births + immigration) – (deaths + emigration)

35. Populations Can Grow, Shrink, or Remain Stable (2) • Age structure • Pre-reproductive age • Reproductive age • Post-reproductive age

36. Some Factors Can Limit Population Size • Range of tolerance • Variations in physical and chemical environment • Limiting factor principle • Too much or too little of any physical or chemical factor can limit or prevent growth of a population, even if all other factors are at or near the optimal range of tolerance • Precipitation • Nutrients • Sunlight, etc

37. Trout Tolerance of Temperature Fig. 5-13, p. 113

38. No Population Can Grow Indefinitely: J-Curves and S-Curves (1) • Size of populations controlled by limiting factors: • Light • Water • Space • Nutrients • Exposure to too many competitors, predators or infectious diseases

39. No Population Can Grow Indefinitely: J-Curves and S-Curves (2) • Environmental resistance • All factors that act to limit the growth of a population • Carrying capacity (K) • Maximum population a given habitat can sustain

40. No Population Can Grow Indefinitely: J-Curves and S-Curves (3) • Exponential growth • Starts slowly, then accelerates to carrying capacity when meets environmental resistance • Logistic growth • Decreased population growth rate as population size reaches carrying capacity

41. Logistic Growth of Sheep in Tasmania Fig. 5-15, p. 115

42. Science Focus: Why Do California’s Sea Otters Face an Uncertain Future? • Low biotic potential • Prey for orcas • Cat parasites • Thorny-headed worms • Toxic algae blooms • PCBs and other toxins • Oil spills

43. Population Size of Southern Sea Otters Off the Coast of So. California (U.S.) Fig. 5-B, p. 114

44. Case Study: Exploding White-Tailed Deer Population in the U.S. • 1900: deer habitat destruction and uncontrolled hunting • 1920s–1930s: laws to protect the deer • Current population explosion for deer • Spread Lyme disease • Deer-vehicle accidents • Eating garden plants and shrubs • Ways to control the deer population

45. Mature Male White-Tailed Deer Fig. 5-16, p. 115

46. When a Population Exceeds Its Habitat’s Carrying Capacity, Its Population Can Crash • A population exceeds the area’s carrying capacity • Reproductive time lag may lead to overshoot • Population crash • Damage may reduce area’s carrying capacity

47. Exponential Growth, Overshoot, and Population Crash of a Reindeer Fig. 5-17, p. 116

48. Species Have Different Reproductive Patterns (1) • Some species • Many, usually small, offspring • Little or no parental care • Massive deaths of offspring • Insects, bacteria, algae

49. Species Have Different Reproductive Patterns (2) • Other species • Reproduce later in life • Small number of offspring with long life spans • Young offspring grow inside mother • Long time to maturity • Protected by parents, and potentially groups • Humans • Elephants

50. Under Some Circumstances Population Density Affects Population Size • Density-dependent population controls • Predation • Parasitism • Infectious disease • Competition for resources