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Ecosystems and Biodiversity Practice Tests

These Grade 9 Biology practice tests explore how biodiversity supports ecosystem structure, function, and resilience. Questions cover genetic, species, and ecosystem diversity; keystone species; ecosystem services; habitat loss; invasive species; pollution; climate change; restoration; and conservation.

Skills covered

  • Distinguishing genetic, species, and ecosystem biodiversity and explaining resilience and resistance
  • Analyzing keystone species, indicator species, trophic cascades, decomposers, and ecosystem services
  • Evaluating habitat loss, fragmentation, edge effects, invasive species, eutrophication, plastic pollution, and climate change
  • Connecting ecological footprints, sustainability, protected areas, corridors, restoration, and native species
  • Interpreting population, food-web, biodiversity, and ecosystem-health evidence for conservation decisions

How to use these practice tests

First identify the ecological level or biodiversity type. Then trace the direct and indirect effects of a disturbance and consider which evidence would support a conservation decision. Review the explanations to strengthen environmental science vocabulary and systems thinking.

For more Grade 9 Science practice, return to the Grade 9 Science category.

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Grade 9 Ecosystems and Biodiversity Practice Tests

Practice Grade 9 Science questions about biodiversity, ecosystem structure, keystone species, ecosystem services, habitat loss, pollution, climate change, and conservation.

Choose the best answer. Identify the level of biodiversity or ecosystem process involved, trace direct and indirect effects, and evaluate conservation choices.

10 Questions
0/10 Questions0 %
Correct 0
Incorrect 0
Unanswered 10
1. QuestionMultiple choice

What is habitat loss?

Please select an answer first.

Correct answer: A

The correct answer is The conversion or destruction of natural habitat so that organisms lose living space and resources..

  1. Identify the ecosystem concept: Determine whether the question focuses on biodiversity, ecosystem structure, environmental change, or conservation.
  2. Apply the ecological principle: Habitat loss occurs when development, agriculture, mining, or other activities remove or alter natural habitat.
  3. Check the answer: The correct answer is The conversion or destruction of natural habitat so that organisms lose living space and resources..

Habitat loss occurs when development, agriculture, mining, or other activities remove or alter natural habitat.

2. QuestionMultiple choice

Why is habitat fragmentation harmful to some populations?

Please select an answer first.

Correct answer: B

The correct answer is It isolates groups, reduces habitat area, and can limit movement and gene flow..

  1. Identify the ecosystem concept: Determine whether the question focuses on biodiversity, ecosystem structure, environmental change, or conservation.
  2. Apply the ecological principle: Fragmentation can isolate populations, increase edge effects, and reduce access to food, mates, and shelter.
  3. Check the answer: The correct answer is It isolates groups, reduces habitat area, and can limit movement and gene flow..

Fragmentation can isolate populations, increase edge effects, and reduce access to food, mates, and shelter.

3. QuestionMultiple choice

What is an edge effect?

Please select an answer first.

Correct answer: C

The correct answer is A change in conditions or species interactions near the boundary of a habitat patch..

  1. Identify the ecosystem concept: Determine whether the question focuses on biodiversity, ecosystem structure, environmental change, or conservation.
  2. Apply the ecological principle: Edges can have different light, temperature, wind, predators, and invasive species than interior habitat.
  3. Check the answer: The correct answer is A change in conditions or species interactions near the boundary of a habitat patch..

Edges can have different light, temperature, wind, predators, and invasive species than interior habitat.

4. QuestionMultiple choice

Why can an invasive species spread rapidly in a new ecosystem?

Please select an answer first.

Correct answer: D

The correct answer is It may lack natural predators, parasites, or competitors that control it in its original range..

  1. Identify the ecosystem concept: Determine whether the question focuses on biodiversity, ecosystem structure, environmental change, or conservation.
  2. Apply the ecological principle: Without its usual controls, an introduced species may expand and disrupt native communities.
  3. Check the answer: The correct answer is It may lack natural predators, parasites, or competitors that control it in its original range..

Without its usual controls, an introduced species may expand and disrupt native communities.

5. QuestionMultiple choice

What is eutrophication?

Please select an answer first.

Correct answer: A

The correct answer is Excess nutrients cause algal growth and oxygen depletion in a body of water..

  1. Identify the ecosystem concept: Determine whether the question focuses on biodiversity, ecosystem structure, environmental change, or conservation.
  2. Apply the ecological principle: Runoff containing nitrogen or phosphorus can fuel algal blooms; decomposition then reduces dissolved oxygen.
  3. Check the answer: The correct answer is Excess nutrients cause algal growth and oxygen depletion in a body of water..

Runoff containing nitrogen or phosphorus can fuel algal blooms; decomposition then reduces dissolved oxygen.

6. QuestionMultiple choice

Why can plastic pollution harm marine ecosystems?

Please select an answer first.

Correct answer: B

The correct answer is Animals may ingest plastic or become entangled, and plastic can persist in the environment..

  1. Identify the ecosystem concept: Determine whether the question focuses on biodiversity, ecosystem structure, environmental change, or conservation.
  2. Apply the ecological principle: Persistent plastic can injure organisms, transport pollutants, and break into small particles that enter food webs.
  3. Check the answer: The correct answer is Animals may ingest plastic or become entangled, and plastic can persist in the environment..

Persistent plastic can injure organisms, transport pollutants, and break into small particles that enter food webs.

7. QuestionMultiple choice

What is bioaccumulation?

Please select an answer first.

Correct answer: C

The correct answer is The buildup of a substance in an individual when intake exceeds removal..

  1. Identify the ecosystem concept: Determine whether the question focuses on biodiversity, ecosystem structure, environmental change, or conservation.
  2. Apply the ecological principle: Some substances accumulate in tissues over an organism's lifetime, especially when they are difficult to break down.
  3. Check the answer: The correct answer is The buildup of a substance in an individual when intake exceeds removal..

Some substances accumulate in tissues over an organism's lifetime, especially when they are difficult to break down.

8. QuestionMultiple choice

How can climate change alter ecosystems?

Please select an answer first.

Correct answer: D

The correct answer is It can shift temperature, precipitation, seasons, ranges, and species interactions..

  1. Identify the ecosystem concept: Determine whether the question focuses on biodiversity, ecosystem structure, environmental change, or conservation.
  2. Apply the ecological principle: Changing climate conditions can alter migration, flowering, breeding, food availability, disease, and geographic ranges.
  3. Check the answer: The correct answer is It can shift temperature, precipitation, seasons, ranges, and species interactions..

Changing climate conditions can alter migration, flowering, breeding, food availability, disease, and geographic ranges.

9. QuestionMultiple choice

What is ocean acidification mainly associated with?

Please select an answer first.

Correct answer: A

The correct answer is Increased absorption of atmospheric carbon dioxide by seawater..

  1. Identify the ecosystem concept: Determine whether the question focuses on biodiversity, ecosystem structure, environmental change, or conservation.
  2. Apply the ecological principle: Carbon dioxide reacts with seawater and can lower pH, making shell formation more difficult for some organisms.
  3. Check the answer: The correct answer is Increased absorption of atmospheric carbon dioxide by seawater..

Carbon dioxide reacts with seawater and can lower pH, making shell formation more difficult for some organisms.

10. QuestionMultiple choice

Why can coral bleaching occur during environmental stress?

Please select an answer first.

Correct answer: B

The correct answer is Corals may lose or expel the symbiotic algae that provide much of their energy..

  1. Identify the ecosystem concept: Determine whether the question focuses on biodiversity, ecosystem structure, environmental change, or conservation.
  2. Apply the ecological principle: Heat and other stressors can disrupt the coral-algae relationship, causing corals to lose color and energy sources.
  3. Check the answer: The correct answer is Corals may lose or expel the symbiotic algae that provide much of their energy..

Heat and other stressors can disrupt the coral-algae relationship, causing corals to lose color and energy sources.

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