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Quiz: Biodiversity and Ecosystem Services

Test your understanding of biodiversity, ecosystem services, island biogeography, ecological tolerance, and succession with these review questions.

1. What are the two components that together determine species diversity?

  1. Species size and species lifespan
  2. Species richness and species evenness
  3. Species abundance and species distribution range
  4. Species age and species reproduction rate
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The correct answer is B. Species diversity has two components: species richness (the total number of different species in an area) and species evenness (how equally individuals are distributed among those species). An area with many species but extreme dominance by one species has lower diversity than an area with the same number of species in more balanced proportions.

Concept Tested: Species Diversity

2. Which category of ecosystem services includes pollination, flood control, and water purification?

  1. Provisioning services
  2. Cultural services
  3. Regulating services
  4. Supporting services
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The correct answer is C. Regulating services are ecosystem processes that regulate environmental conditions. Pollination by insects and birds enables plant reproduction, wetlands absorb floodwaters, and soil and plant roots filter pollutants from water. These services differ from provisioning services (tangible products), cultural services (non-material benefits), and supporting services (foundational processes like nutrient cycling).

Concept Tested: Regulating Services

3. According to island biogeography theory, which island would be expected to have the highest species richness?

  1. A small island far from the mainland
  2. A large island far from the mainland
  3. A small island close to the mainland
  4. A large island close to the mainland
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The correct answer is D. According to MacArthur and Wilson's theory of island biogeography, species richness is determined by the balance between immigration and extinction rates. Large islands support more species because they have more habitats and larger populations, reducing extinction rates. Islands close to the mainland receive more colonists, increasing immigration rates. A large, nearby island maximizes both factors.

Concept Tested: Island Biogeography

4. What distinguishes primary succession from secondary succession?

  1. Primary succession occurs only in aquatic environments while secondary succession occurs on land
  2. Primary succession takes place on bare substrate with no soil while secondary succession occurs where soil remains
  3. Primary succession is caused by human activity while secondary succession is caused by natural events
  4. Primary succession involves only plants while secondary succession involves both plants and animals
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The correct answer is B. Primary succession begins on bare rock or new surfaces where no soil exists, such as after a volcanic eruption or glacier retreat. Pioneer species like lichens and mosses must build soil from scratch, making the process very slow (500-1,000+ years). Secondary succession occurs where soil is already present after a disturbance like fire or abandoned farmland, allowing much faster recovery (100-200 years).

Concept Tested: Primary Succession

5. What traits make pioneer species effective at colonizing disturbed environments?

  1. Slow growth, deep root systems, and shade tolerance
  2. Large body size, long lifespans, and specialized diets
  3. Rapid reproduction, high tolerance for extreme conditions, and effective dispersal
  4. Dependence on mycorrhizal fungi, narrow ecological tolerance, and low seed production
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The correct answer is C. Pioneer species share key traits that enable them to colonize harsh or bare environments: rapid reproduction and growth, high tolerance for extreme conditions such as full sun and poor soil, effective dispersal mechanisms like wind-blown seeds or spores, and the ability to survive on minimal nutrients. These traits allow them to establish first, but they are gradually replaced by better competitors as conditions improve.

Concept Tested: Pioneer Species

6. Why does the species-area relationship matter for conservation?

  1. It proves that all species can survive in any size habitat
  2. It shows that reducing habitat area leads to predictable loss of species
  3. It demonstrates that species richness is independent of habitat size
  4. It indicates that smaller reserves are more effective than larger ones
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The correct answer is B. The species-area relationship (S = cA^z) shows that as habitat area decreases, the number of species it can support also decreases in a predictable way. A tenfold decrease in area roughly halves species richness. This principle is critical for conservation because habitat loss and fragmentation effectively create smaller "islands" of habitat, leading to species loss. It guides decisions about the size of nature reserves and wildlife corridors.

Concept Tested: Species-Area Relationship

7. What is the difference between a generalist species and a specialist species in terms of ecological tolerance?

  1. Generalists have broad tolerance ranges for many factors while specialists have narrow tolerance ranges
  2. Generalists are always larger than specialists and need more resources
  3. Generalists are found only in temperate biomes while specialists live in tropical biomes
  4. Generalists reproduce more slowly than specialists but live longer
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The correct answer is A. Generalist species like raccoons and dandelions have broad tolerance ranges for many environmental factors, allowing them to survive in diverse conditions. Specialist species like koalas (eucalyptus only) and giant pandas (bamboo only) have narrow tolerance ranges and are adapted to specific conditions. Specialists are often more vulnerable to environmental change because they have less ability to adjust to new conditions.

Concept Tested: Ecological Tolerance

8. Which of the following is an example of a supporting ecosystem service?

  1. Harvesting timber from a managed forest
  2. Enjoying a scenic mountain view during a hike
  3. Nutrient cycling through decomposition of organic matter
  4. Wetlands filtering pollutants from agricultural runoff
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The correct answer is C. Supporting services are the foundational processes that make all other ecosystem services possible. Nutrient cycling through decomposition recycles essential elements like carbon, nitrogen, and phosphorus, enabling primary production and soil formation. Timber harvest is a provisioning service, scenic enjoyment is a cultural service, and water filtration is a regulating service.

Concept Tested: Supporting Services

9. Why do most ecologists today question the concept of a true climax community?

  1. Because no ecosystem has ever been observed to reach a stable state
  2. Because disturbances occur too frequently and climate change continuously shifts conditions
  3. Because pioneer species always prevent later species from establishing
  4. Because succession only occurs in tropical ecosystems with high rainfall
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The correct answer is B. While the climax community concept is useful for understanding succession, most ecologists now recognize that true stability is rare. Disturbances such as fires, storms, and droughts occur frequently enough to reset succession before a stable endpoint is reached. Additionally, ongoing climate change continuously shifts the conditions that determine which species can thrive in any given location. A more modern view sees ecosystems as always in flux.

Concept Tested: Climax Community

10. How does ecosystem diversity provide resilience at the landscape level?

  1. All ecosystems within a landscape respond identically to disturbances
  2. Ecosystem diversity eliminates the need for species diversity within individual habitats
  3. Different ecosystems respond differently to stress, so some continue functioning when others are damaged
  4. Ecosystem diversity increases the frequency of natural disruptions across the landscape
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The correct answer is C. A landscape with high ecosystem diversity contains many different habitat types -- forests, wetlands, grasslands, and others. When a drought devastates grasslands, nearby wetlands and forests may continue functioning and providing services. This variety acts as nature's backup plan, ensuring that the landscape as a whole maintains ecological function even when individual ecosystems are stressed or damaged.

Concept Tested: Ecosystem Diversity