Level 1
What is the relationship between biodiversity and sustainability?
a) The more biodiversity an ecosystem has, the more stable and sustainable it is
b) Ecosystems with high biodiversity are more fragile
c) Biodiversity does not affect sustainability
d) High biodiversity reduces the number of available resources
Answer: a
Explanation: Biodiversity increases the resilience of ecosystems, allowing them to recover from disturbances and maintain stability over time.
Answer: a
Explanation: Biodiversity increases the resilience of ecosystems, allowing them to recover from disturbances and maintain stability over time.
Why do some ecosystems never reach a climax community?
a) They do not experience succession
b) Continuous disturbances prevent stability
c) The ecosystem is too biodiverse
d) The climate is too stable for succession
Answer: b
Explanation: Repeated disturbances, such as fires or human activities, can prevent ecosystems from reaching equilibrium.
What happens if an ecosystem loses biodiversity?
a) The ecosystem becomes more resilient to changes
b) The ecosystem is less stable and may collapse
c) Succession occurs at a faster rate
d) There is no impact on sustainability
Answer: b
Explanation: A loss of biodiversity makes an ecosystem more vulnerable to disturbances, reducing its sustainability.
What is the final stage of ecological succession?
a) Pioneer species stage
b) Climax community
c) Secondary succession
d) Habitat destruction
Answer: b
Explanation: The climax community is a stable, mature ecosystem that has reached equilibrium after succession.
In a garden, weeds start growing in an area where the soil was disturbed. What type of succession is this an example of?
a) Primary succession
b) Secondary succession
c) Climax community
d) Biodiversity expansion
Answer: b
Explanation: The soil remains, and fast-growing plants like weeds quickly take over, making this secondary succession.
How do natural disasters affect succession?
a) They restart succession by removing organisms
b) They prevent species from adapting to their environment
c) They cause ecosystems to stop functioning permanently
d) They do not impact ecosystems in any way
Answer: a
Explanation: Disasters like fires and floods remove vegetation but allow succession to restart, gradually rebuilding ecosystems.
How does a climax community maintain ecosystem stability?
a) By preventing species diversity
b) By having a balanced food web and nutrient cycles
c) By stopping natural succession
d) By limiting interactions between species
Answer: b
Explanation: A climax community reaches a stable equilibrium where species interactions sustain the ecosystem.
Why do some species disappear during succession?
a) They are outcompeted by new species better suited to the environment
b) The climate changes too drastically for any species to survive
c) The ecosystem prevents new species from growing
d) The presence of decomposers eliminates all plant life
Answer: a
Explanation: Over time, more competitive species replace earlier species, leading to shifts in biodiversity.
Which of the following would most likely lead to primary succession?
a) A hurricane damaging a coastal wetland
b) A flood washing away topsoil
c) A glacier retreating, exposing bare rock
d) A forest fire burning through trees but leaving the soil
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Answer: c
Explanation: The newly exposed land lacks soil, requiring pioneer species to initiate primary succession.
Which of the following best explains why ecological succession occurs?
a) To allow organisms to adapt to climate change
b) Because new species are constantly evolving
c) To restore balance to an ecosystem after a disturbance
d) As a natural way to eliminate invasive species
Answer: c
Explanation: Succession is nature’s way of rebuilding ecosystems after a disturbance, ensuring they return to a stable state over time.
What is one way to restore biodiversity in an ecosystem?
a) Introduce non-native species to fill ecological roles
b) Reduce pollution and conserve natural habitats
c) Prevent natural succession from occurring
d) Eliminate predators from the food web
Answer: b
Explanation: Protecting habitats and reducing pollution supports species diversity and ecosystem sustainability.
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How does a climax community maintain ecosystem stability?
a) By preventing species diversity
b) By having a balanced food web and nutrient cycles
c) By stopping natural succession
d) By limiting interactions between species
How does a climax community maintain ecosystem stability?
a) By preventing species diversity
b) By having a balanced food web and nutrient cycles
c) By stopping natural succession
d) By limiting interactions between species
.
Answer: b
Explanation: A climax community reaches a stable equilibrium where species interactions sustain the ecosystem.
What factor determines how quickly succession occurs in an ecosystem?
a) The presence of water and soil
b) The number of predators in the ecosystem
c) The amount of human development in the area
d) The temperature of the ecosystem
Answer: a
Explanation: The availability of water and soil helps plants establish themselves, speeding up succession.
How do humans negatively impact ecological succession?
a) By protecting endangered species
b) By introducing invasive species that disrupt ecosystems
c) By preventing deforestation
d) By restoring natural habitats
Answer: b
Explanation: Invasive species compete with native species, slowing down or changing natural succession patterns.
How does biodiversity contribute to the sustainability of an ecosystem?
a) By limiting the number of species to prevent overcrowding
b) By providing various species that can perform different ecological roles
c) By reducing the number of organisms that can compete for resources
d) By preventing succession from occurring in the ecosystem
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Answer: b
Explanation: Biodiversity increases an ecosystem’s resilience, ensuring that different species contribute to food chains, nutrient cycles, and habitat stability.
How can humans disrupt ecological succession?
a) By replanting trees in deforested areas
b) By preventing invasive species from spreading
c) By clearing land for agriculture or urban development
d) By protecting natural habitats
Answer: c
Explanation: Human activities like deforestation and urbanization disrupt succession by removing vegetation and altering landscapes.
In a newly formed volcanic island, which organisms would appear first?
a) Large trees
b) Lichens and mosses
c) Fish and amphibians
d) Carnivores
Answer: b
Explanation: Lichens and mosses help break down rock to form soil, allowing later plant species to grow.
How can human activities speed up succession?
a) By introducing invasive species
b) By planting native trees and restoring habitats
c) By removing biodiversity from an ecosystem
d) By disrupting the food web
Answer: b
Explanation: Humans can accelerate succession by restoring ecosystems through reforestation and conservation efforts.
Why does secondary succession occur faster than primary succession?
a) The climate is better suited for plant growth
b) Soil is already present, allowing plants to regrow more quickly
c) Animals return first and help rebuild the ecosystem
d) Humans actively speed up the process
Answer: b
Explanation: Since soil already exists, plants can grow quickly without waiting for rock to break down.
What type of event would most likely lead to secondary succession?
a) Lava hardening into rock
b) A glacier retreating and exposing bare land
c) A wildfire burning through a forest
d) An asteroid impact wiping out all life in an area
Answer: c
Explanation: A wildfire destroys vegetation but leaves the soil intact, allowing plants to regrow, making it an example of secondary succession.
Why is succession important for the environment?
a) It restores ecosystems after natural disasters
b) It removes species diversity from an ecosystem
c) It eliminates competition between organisms
d) It prevents the growth of new plant species
Answer: a
Explanation: Succession ensures that ecosystems recover from disturbances and maintain biodiversity.
How does ecological succession impact species diversity over time?
a) It decreases species diversity permanently
b) It increases species diversity as new organisms colonize the area
c) It keeps species diversity the same
d) It eliminates biodiversity from ecosystems
Answer: b
Explanation: As succession progresses, more species establish themselves, leading to greater biodiversity.
What role do decomposers play in ecological succession?
a) They compete with pioneer species for resources
b) They break down dead organisms, returning nutrients to the soil
c) They cause disturbances that slow succession
d) They prevent biodiversity from increasing
Answer: b
Explanation: Decomposers recycle nutrients, helping soil development and allowing new plant growth.
Answer: b
Explanation: Decomposers recycle nutrients, helping soil development and allowing new plant growth.
Which of the following is a pioneer species in primary succession?
a) Oak trees
b) Grass
c) Lichens
d) Insects
Answer: c
Explanation: Lichens are one of the first organisms to colonize bare rock, helping to create soil for other plants
What is the main difference between primary and secondary succession?
a) Primary succession occurs only in water, while secondary occurs on land
b) Primary starts without soil, while secondary starts with soil already present
c) Primary succession is caused by humans, while secondary is caused by natural disasters
d) Secondary succession is faster but results in fewer species than primary succession
Answer: b
Explanation: In primary succession, soil must form before plants can grow, making it a much slower process. In secondary succession, since soil remains, plants can quickly reestablish themselves.