1. Do Now:
Identify and describe the different species interactions you can remember from living environment?

2. Aim: 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.

3. Core Case Study: Southern Sea Otters: Are They Back from the Brink of Extinction?
Live in kelp forests
Eat sea urchins
Hunted: early 1900s
1977 declared endangered
increased 300 to 2800
Why care about sea otters?
Ethics
Tourism dollars
Keystone species

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

5. What is competition?
Competition: two species share a requirement for a
limited resource

6. Types of Competition Intraspecific Competition: between
individuals of the SAME species
Interspecific Competition: between
individuals of DIFFERENT species

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

8. Black-throated Green Warbler Yellow-rumped Warbler
Resource Partitioning Among Warblers
Blackburnian Warbler
Black-throated Green Warbler
Cape May Warbler
Bay-breasted Warbler
Yellow-rumped Warbler
Figure 5.2: Sharing the wealth: This diagram illustrates resource partitioning among five species of insect-eating warblers in the spruce forests of the U.S. state of Maine. Each species minimizes competition with the others for food by spending at least half its feeding time in a distinct portion (yellow highlighted areas) of the spruce trees, and by consuming somewhat different insect species. (After R. H. MacArthur, “Population Ecology of Some Warblers in Northeastern Coniferous Forests,” Ecology 36 (1958): 533–536.)
How have the Warblers learned to co-exist?
Fig. 5-2, p. 106

9. Specialist Species of Honeycreepers
Figure 5.3: Specialist species of honeycreepers: Through natural selection, different species of honeycreepers developed specialized ecological niches that reduced competition between these species. Each species has evolved a specialized beak to take advantage of certain types of food resources.
Fig. 5-3, p. 107

10. Predator-Prey Relationships
Figure 5.4: Predator-prey relationship: This brown bear (the predator) in the U.S. state of Alaska has captured and will feed on this salmon (the prey).
Fig. 5-4, 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. 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

13. (b) Wandering leaf insect
(a) Span worm
(b) Wandering leaf insect
(c) Bombardier beetle
(d) Foul-tasting monarch butterfly
(e) Poison dart frog
(f) Viceroy butterfly mimics
monarch butterfly
(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

14. Pause…Write…Discuss
Describe a trait possessed by the southern sea otter that helps it to catch prey and a trait that helps it to avoid being preyed upon.

15. 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

16. 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

17. Importance: Cheetahs are fast which cause antelope to become faster
Co-evolution: Evolution Arms Race Predator and Prey Interactions Can Drive Each Other’s Evolution
Process by which two or more species evolve in response to one another.
Prey and predator can become locked in a duel of escalating adaptation. Example: cheetah and antelope
Importance: Cheetahs are fast which cause antelope
to become faster
in order to survive.

18. Parasitism (+,-)
Some species feed off other species by living on or in them.
Parasite is usually much smaller than the host
Parasite rarely kills the host
Parasite-host interaction may lead to coevolution

19. Mutualism (+,+) Both species benefit
Nutrition and protection relationship
Gut inhabitant mutualism
Not cooperation: it’s mutual exploitation

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

21. Commensalism (+,0) One species benefits and the other is not harmed
Epiphytes
Birds nesting in trees

22. Summary:
What difference would it make if the southern sea otter became extinct mostly because of human activities? What are three things we could do to help prevent the extinction of this species?

23. Do Now:
What factors can limit the growth of a population?

24. Aim: 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.

25. What are populations?
Population: group of interbreeding individuals of the same species

26. Most Populations Live Together in Clumps or Patches (2)
Why clumping?
Cluster where resources are available
Better chance of finding clumped resources
Protects some animals from predators
Packs allow some to get prey
Population of Snow Geese

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

28. Population’s Age Structures
Pre-reproductive age: not mature enough to reproduce
Reproductive age: capable of reproduction
Post-reproductive age: too old to reproduce

29. 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,
Precipitation
Nutrients
Sunlight, etc

30. Limiting Factor
DEFINITION: anything that tends to make it more difficult for a species to live and grow or reproduce in its environment
ABIOTIC: temperature, water, climate/weather, soils
BIOTIC : competition, predation/parasitism, mutualism

31. Trout Tolerance of Temperature
Range of Tolerance: variations in physical and chemical
environment
Figure 5.13: This diagram illustrates the range of tolerance for a population of organisms, such as trout, to a physical environmental factor—in this case, water temperature. Range of tolerance restrictions prevent particular species from taking over an ecosystem by keeping their population size in check. Question: For humans, what is an example of a range of tolerance for a physical environmental factor?
Fig. 5-13, p. 113

32. Limits to Population Growth
Biotic potential: capacity for growth
Intrinsic rate of increase (r): rate at
which a population would grow if it had unlimited resources.
Environmental resistance: all factors that act to limit the growth of a population.
Carrying Capacity (K): maximum # of individuals of a given species that can be sustained indefinitely in a given space (area or volume)

33. Pause…Write…Discuss
What is an example of environmental resistance that humans have not been able to overcome?

34. Exponential and Logistic Growth
Exponential (J shape)
Logistic (S shape)
Population w/few resource
limitations; grows at a fixed rate
Decreased population growth rate as reaches carrying capacity
Rapid exp. growth followed by steady dec. in pop. growth w/time until pop. size levels off

35. Logistic Growth of Sheep in Tasmania
Figure 5.15: This graph tracks the logistic growth of a sheep population on the island of Tasmania between 1800 and After sheep were introduced in 1800, their population grew exponentially, thanks to an ample food supply and few predators. By 1855, they had overshot the land’s carrying capacity. Their numbers then stabilized and fluctuated around a carrying capacity of about 1.6 million sheep.
Fig. 5-15, p. 115

36. 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

37. Pause…Write…Discuss
Some people blame the white tailed deer for invading farms and suburban yards and gardens to eat food. Others say humans are mostly to blame because they have invaded deer territory and eliminated most of their predators. Which view do you hold? Why? Do you have a solution to this problem?

38. Population Crash: Exceeding a Habitats Carrying Capacity,
A population exceeds the area’s carrying capacity
Reproductive time lag may lead to overshoot
Population crash
Damage may reduce area’s carrying capacity

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

40. 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

41. Several Different Types of Population Change Occur in Nature
Stable
Irruptive
Population surge, followed by crash
Cyclic fluctuations, boom-and-bust cycles
Top-down population regulation
Bottom-up population regulation
Irregular: no pattern

42. Population Cycles for the Snowshoe Hare and Canada Lynx
Figure 5.18: This graph represents the population cycles for the snowshoe hare and the Canadian lynx. At one time, scientists believed these curves provided evidence that these predator and prey populations regulated one another. More recent research suggests that the periodic swings in the hare population are caused by a combination of top-down population control—through predation by lynx and other predators—and bottom-up population control, in which changes in the availability of the food supply for hares help to determine their population size, which in turn helps to determine the lynx population size. (Data from D. A. MacLulich)
Fig. 5-18, p. 118

43. Humans Are Not Exempt from Nature’s Population Controls
Ireland
Potato crop in 1845
Bubonic plague
Fourteenth century
AIDS
Global epidemic

44. Summary:
Can we continue to expand the Earth’s carrying capacity for humans? Explain your answer in complete sentences.

45. Do Now: Movie Clip
Answer the following questions while watching the clip:
1) What is ecological succession?
2) What is the difference between primary and secondary ecological succession?

46. Aim: How Do Communities and Ecosystems Respond to Changing Environmental Conditions?
Concept 5-3 The structure and species composition of communities and ecosystems change in response to changing environmental conditions through a process called ecological succession.

47. Communities and Ecosystems Change over Time: Ecological Succession
Natural ecological restoration
Primary succession
Secondary succession

48. Some Ecosystems Start from Scratch: Primary Succession
No soil in a terrestrial system
No bottom sediment in an aquatic system
Takes hundreds to thousands of years
Need to build up soils/sediments to provide necessary nutrients

49. Primary Ecological Succession
Figure 5.19: Primary ecological succession: Over almost a thousand years, these plant communities developed, starting on bare rock exposed by a retreating glacier on Isle Royal, Michigan (USA) in northern Lake Superior. The details of this process vary from one site to another. Question: What are two ways in which lichens, mosses, and plants might get started growing on bare rock?
Balsam fir, paper birch, and white spruce forest community
Jack pine, black spruce, and aspen
Heath mat
Small herbs and shrubs
Lichens and mosses
Exposed rocks
Time
Fig. 5-19, p. 119

50. Some Ecosystems Do Not Have to Start from Scratch: Secondary Succession (1)
Some soil remains in a terrestrial system
Some bottom sediment remains in an aquatic system
Ecosystem has been
Disturbed
Removed
Destroyed

51. Secondary Succession Mature oak and hickory forest
Figure 5.20: Natural ecological restoration of disturbed land: This diagram shows the undisturbed secondary ecological succession of plant communities on an abandoned farm field in the U.S. state of North Carolina. It took 150–200 years after the farmland was abandoned for the area to become covered with a mature oak and hickory forest. A new disturbance such as deforestation or fire would create conditions favoring pioneer species such as annual weeds. In the absence of new disturbances, secondary succession would recur over time, but not necessarily in the same sequence shown here. See an animation based on this figure at CengageNOW. Questions: Do you think the annual weeds (left) would continue to thrive in the mature forest (right)? Why or why not?
Mature oak and hickory forest
Young pine forest with developing understory of oak and hickory trees
Shrubs and small pine seedlings
Perennial weeds and grasses
Annual weeds
Time
Fig. 5-20, p. 120

52. Secondary Ecological Succession in Yellowstone Following the 1998 Fire
Figure 5.21: These young lodgepole pines growing around standing dead trees after a 1998 forest fire in Yellowstone National Park are an example of secondary ecological succession.
Fig. 5-21, p. 120

53. Some Ecosystems Do Not Have to Start from Scratch: Secondary Succession (2)
Primary and secondary succession
Tend to increase biodiversity
Increase species richness and interactions among species
Succession can be interrupted by
Fires
Hurricanes
Clear-cutting of forests
Plowing of grasslands
Invasion by nonnative species

54. Succession Doesn’t Follow a Predictable Path
Traditional view
Balance of nature and a climax community
Current view
Ever-changing mosaic of patches of vegetation
Mature late-successional ecosystems
State of continual disturbance and change

55. Living Systems Are Sustained through Constant Change
Inertia, persistence
Ability of a living system to survive moderate disturbances
Resilience
Ability of a living system to be restored through secondary succession after a moderate disturbance
Some systems have one property, but not the other: tropical rainforests

56. Three Big Ideas
Certain interactions among species affect their use of resources and their population sizes.
There are always limits to population growth in nature.
Changes in environmental conditions cause communities and ecosystems to gradually alter their species composition and population sizes (ecological succession).