2. This lecture will help you understand:
Species interactions
Feeding relationships, energy flow, trophic levels, and food webs
Keystone species
The process of succession
Potential impacts of invasive species
Restoration ecology
Terrestrial biomes

3. By 2010, they had invaded 30 states
Central Case Study: Black and White and Spread All Over: Zebra Mussels Invade the Great Lakes
In 1988, zebra mussels were accidentally introduced to Lake St. Clair in discharged ballast water
By 2010, they had invaded 30 states
No natural predators, competitors, or parasites
They cause millions of dollars of damage to property each year

6. Species Interactions Natural species interactions: Competition?
Exploitative = one species benefits and the other is harmed
What are examples of exlploitative relationships?
Mutualism?

7. Competition can occur when resources are limited
In competition, multiple organisms seek the same limited resources and all competitors suffer (/ interaction)
What are some examples that organisms will be in competition for?
Intraspecific competition?
Low or high population density leads to decreased or increased competition

8. Competition can occur when resources are limited
Interspecific competition?
Strongly affects community composition
Leads to competitive exclusion or species coexistence

9. Competition can occur when resources are limited
Competitive exclusion
Species coexistence?
What does species coexistence produce?
How do species minimize competition?

10. Competition can occur when resources are limited
Fundamental niche?
Realized niche?

12. Competition can occur when resources are limited
Resource partitioning?

14. Competition can occur when resources are limited
Character displacement?
What is an example of character displacement?
Competition is reduced when two species become more different

15. Several types of interactions are exploitative
Exploitation = process by which one member exploits another for its own gain (/ interactions)
Predation, parasitism, herbivory
Predation?
What does it structure?

16. Parasites exploit living hosts
Parasitism?
What happens to the host with a parasite?
Some parasites are ________________
Infrequent contact with their hosts
Some________________within the host
What are pathogens? 16

17. Parasites exploit living hosts
Parasitoids?
Coevolution?
Has been called an________________________ 17

18. Herbivores exploit plants
Herbivory?
Defenses against herbivory include:
What are some examples of defenses?
Like in parasitism, herbivore–plant interaction can result in coevolution. 18

19. Mutualists help one another
Mutualism?
Symbiosis?
Examples?
Pollination? 19

20. Energy passes among trophic levels
Matter and energy move through the community
Trophic level?
List the trophic levels in order? 20

22. Producers Producers, or autotrophs (“self-feeders”)?
What are examples of producers? 22

23. Consumers Primary consumers? Secondary consumers?
Organisms that consume producers
Herbivores? What are some examples?
Secondary consumers?
Organisms that prey on primary consumers
Carnivores? What are some examples? 23

24. Consumers Tertiary consumers? Omnivores?
Predators at the highest trophic level
Consume secondary consumers
What are some examples of tertiary consumers?
Omnivores?

25. Detritivores and decomposers
What do these organisms do?
Detritivores? What are some examples?
Decomposers? What are some examples? 25

26. Energy, biomass, and numbers decrease at higher trophic levels
Most energy organisms use is lost as waste heat through cellular respiration
Less and less energy is available in each successive trophic level
Each level contains only about 10% of the energy of the trophic level below it
There are also far fewer organisms and less biomass (mass of living matter) at each higher trophic level
A human vegetarian’s ecological footprint is smaller than a meat-eater’s footprint 26

28. Food webs show feeding relationships and energy flow
Food chain?
Food web? 28

30. Some organisms play outsized roles in communities
Community dynamics are complex
Species interactions differ in strength
Keystone species?
Removal of a keystone species has substantial ripple effects
What happens when keystone species are removed?

32. Some organisms play outsized roles in communities
Trophic cascade?

33. Communities respond to disturbance in various ways
What are some examples?

34. Communities respond to disturbance in various ways
Communities have different ways of maintaining themselves when disturbed
Resistance?
Resilience?
A disturbed community may never return to its original state

35. Succession follows severe disturbance
Primary succession?
Pioneer species?

36. Succession follows severe disturbance
Secondary succession?
The remaining organisms and soil form “building blocks” that help shape the process of succession
Fires, hurricanes, farming, logging
Climax community?

37. Communities may undergo shifts
The dynamics of community change are more variable and less predictable than thought
Competition may inhibit progression to another stage
Chance factors also affect movement between stages
Climax community may not be based on climate alone
Phase (regime) shift?
Some crucial threshold is passed, a keystone species is lost, or an exotic species invades
Novel or no-analog communities?

38. Invasive species pose new threats to community stability
Introduced species?

40. Prevention, rather than control, is the best policy
We can respond to invasive species through control, eradication, or prevention
Techniques to control invasive species
Removing them manually
Applying toxic chemicals
Introducing native predators or diseases
Stressing them with heat, sound, electricity, carbon dioxide, or ultraviolet light
Control and eradication are hard and expensive
Understanding the biology of invasive species can help predict where they will be a problem
Prevention, rather than control, is the best policy

41. Altered communities can be restored
Humans have dramatically changed ecological systems
Severely degraded systems cease to function
Ecological restoration = efforts to restore communities
Restoration is informed by restoration ecology = the science of restoring an area to an earlier condition to restore the system’s functionality (e.g., filtering of water by a wetland)
It is difficult, time-consuming, and expensive
It is best to protect natural systems from degradation in the first place

42. Earth’s Biomes
Widely separated regions share similarities
Biome?

44. Climate influences the location of biomes
The type of biome depends on abiotic factors
Temperature, precipitation, soil type, atmospheric circulation
Climatograph?
Similar latitudes have similar climates
Similar biomes occupy similar latitudes

46. Aquatic and coastal systems resemble biomes
Various aquatic systems comprise distinct communities
Coastlines, continental shelves
Open ocean, deep sea
Coral reefs, kelp forests
Freshwater lakes and rivers
Some coastal systems (estuaries, marshes, etc.) have both aquatic and terrestrial components

47. Aquatic and coastal systems resemble biomes
Aquatic systems are shaped by
Water temperature, salinity, and dissolved nutrients
Wave action, currents, depth, light levels
Substrate type and animal and plant life

48. Biomes For each biome construct a chart with characteristics. Location
Climate
Soil
Plants
Animals

49. Temperate deciduous forest
Deciduous trees lose their leaves each fall
They remain dormant during winter
Mid-latitude forests in Europe, eastern China, eastern North America
Even, year-round precipitation
Fertile soils
Dominant forests trees are often oak, beech, maple

51. Temperate grasslands Less precipitation Also called steppe or prairie
More extreme temperature difference between winter and summer than temperate deciduous forest
Less precipitation
Also called steppe or prairie
Once widespread, but has been converted to agriculture
Bison, prairie dogs, ground-nesting birds, pronghorn

53. Temperate rainforest Coastal Pacific Northwest
Great deal of precipitation
Coniferous trees: cedar, spruce, hemlock, fir
Moisture-loving animals
Banana slug
Erosion and landslides affect the fertile soil
Logged for lumber and paper
Most old growth is gone

55. Tropical rainforest
Southeast Asia, west Africa, Central and South America
Year-round rain and warm temperatures
Forest floor is dark and damp
Lush vegetation
Diverse species
But species in low densities
Very poor, acidic soils

57. Tropical dry forest Also called tropical deciduous forest
Plants drop leaves during the dry season
India, Africa, South America, north Australia
Wet and dry seasons
Warm, but seasonal rainfall and less overall than rainforest
Converted to agriculture
Severe soil erosion

59. Savanna Grassland interspersed with trees
Africa, South America, Australia, India
Precipitation is only during the rainy season
Animals gather near water holes
Zebras, gazelles, giraffes, lions, hyenas

61. Desert Minimal precipitation Some are bare, with sand dunes (Sahara)
Some are vegetated (Sonoran)
They are not always hot
Temperatures vary widely during the day
Saline soils
Animals are often nocturnal, nomadic
Plants may have thick skins, spines to protect their water

63. Tundra Russia, Canada, Scandinavia Minimal precipitation
Extremely cold winters
Extreme variation in day length
Permafrost = permanently frozen soil
Melting due to climate change
Few animals: polar bears, musk oxen, caribou, migratory birds
Lichens, low vegetation, few trees

65. Boreal forest Also called taiga Canada, Alaska, Russia, Scandinavia
Extends for large continuous areas
A few evergreen tree species
Cool and dry climate
Long, cold winters
Short, cool summers
Nutrient-poor, acidic soil
Moose, wolves, bears, lynx, migratory birds

67. Chaparral Occurs in small patches around the globe
Mediterranean Sea, coastal Chile, California, southern Australia
Highly seasonal biome
Mild, wet winters
Warm, dry summers
Frequent fires
Densely thicketed, evergreen shrubs

69. Altitudes create patterns analogous to latitudinal
Vegetative communities change along mountain slopes
The climate varies with altitude in the same way it varies with latitude
A mountain climber in the Andes begins in the tropics and ends on a glacier
Rainshadow effect = phenomenon that occurs when air going over a mountain releases moisture on one side, creating an arid region on the other side
Hiking up a mountain in the southwest U.S. is like walking from Mexico to Canada

71. Conclusion
Biomes and communities help us understand how the world functions
Species interactions affect communities
Predation, parasitism, competition, mutualism
Cause weak and strong, direct and indirect effects
Feeding relationships are represented by trophic levels and food webs
Humans have altered many communities
Ecological restoration attempts to undo the negative changes that we have caused

72. QUESTION: Review Mutualism is a form of species interaction where
both species are harmed.
one species benefits, but the other is harmed.
both species benefit.
one species excludes another from a particular area.
Answer: c

73. QUESTION: Review
Which of the following is NOT an exploitative interaction?
Predation
Herbivory
Parasitism
All of these are exploitative interactions.
Answer: d

74. QUESTION: Review An example of resource partitioning is
one species eating larger berries and another species eating smaller berries.
one species moving out of an area to find new resources.
a host species becoming more vulnerable to parasitism.
a pine tree evolving thicker pinecones to reduce consumption by squirrels.
Answer: a

75. QUESTION: Review Which statement about trophic levels is NOT true?
Plants are autotrophs and occupy the first trophic level.
Detritivores consume waste products or dead bodies.
Biomass and energy decrease going up the food chain.
There are more predator individuals than prey individuals in a typical area.
Answer: d

76. QUESTION: Review
Primary succession would take place on all of the following EXCEPT
the slopes of a newly formed volcanic island.
a forest in northwest Oregon after it had been logged.
a receding glacier.
a drying lake.
Answer: b

77. QUESTION: Review
Because communities can undergo phase (regime) shifts, we must remember that
secondary succession results in a predictable series of stages.
we can count on being able to reverse damage caused by human disturbance.
we cannot count on being able to reverse damage caused by human disturbance.
changes humans set in motion will not be permanent.
Answer: c

78. QUESTION: Review
All of the following are ways to control invasive species EXCEPT
removing individuals from the area.
stressing them by noise.
introducing a predator.
encouraging them to hybridize with another species.
Answer: d

79. QUESTION: Review
Which biome has year-round rain and warm temperatures, is dark and damp, and has lush vegetation?
Tropical rainforest
Temperate grasslands
Chaparral
Taiga
Answer: a

80. QUESTION: Review
Which biome is dominated by a few evergreen species, has long, cold winters, and has moose, wolves, bear, and lynx?
Tropical rainforest
Temperate grasslands
Temperate rainforest
Taiga
Answer: d

81. QUESTION: Weighing the Issues
Would you be willing to decrease the amount of meat you consume (i.e., eat lower on the food chain) to decrease your ecological footprint?
Yes, if the extra food was sent to countries with starving people.
Yes, because it would decrease environmental degradation.
I don’t eat meat now.
No, I don’t see the need to eat lower on the food chain.
Answer: any

82. QUESTION: Weighing the Issues
Although mustangs are not native to the United States, they exist in several western states on federally owned land. As an introduced species, what should be done with them?
As an exotic species, they should immediately be removed and adopted or killed.
Although they are an exotic species, they are part of our heritage and should be allowed to stay.
They have been here so long, we should just leave them alone.
Many countries eat horse flesh, so we should round them up and export them to horse-eating countries.
Answer: any

83. QUESTION: Interpreting Graphs and Data
What does this figure illustrate?
A predator–prey cycle
Competitive exclusion
Resource partitioning
Succession
Answer: c

84. QUESTION: Interpreting Graphs and Data
According to this climatograph for Vaigach, Russia, in the tundra biome, winters are
long and warm.
short and cool.
long and cold.
short and warm.
Answer: c