Ecosystem MCQs

1. An ecosystem is best defined as:
A) A group of organisms
B) Interaction between living and non-living components
C) Only plants in an area
D) Only animals in an area
Answer: B
The term ecosystem was first coined by:
A) Charles Darwin
B) Ernst Haeckel
C) A.G. Tansley
D) Mendel
Answer: C
Which of the following is a biotic component?
A) Water
B) Soil
C) Plants
D) Temperature
Answer: C
Which is an abiotic component?
A) Bacteria
B) Fungi
C) Air
D) Animals
Answer: C
Producers in an ecosystem are:
A) Herbivores
B) Carnivores
C) Green plants
D) Decomposers
Answer: C
Primary consumers are:
A) Carnivores
B) Herbivores
C) Omnivores
D) Decomposers
Answer: B
Secondary consumers mainly feed on:
A) Plants
B) Herbivores
C) Sunlight
D) Soil
Answer: B
Tertiary consumers are:
A) Producers
B) Top carnivores
C) Herbivores
D) Decomposers
Answer: B
Decomposers include:
A) Lions
B) Grass
C) Bacteria
D) Fish
Answer: C
Energy enters the ecosystem through:
A) Soil
B) Sunlight
C) Water
D) Air
Answer: B
The process by which plants make food is:
A) Respiration
B) Photosynthesis
C) Digestion
D) Fermentation
Answer: B
Food chain represents:
A) Energy flow
B) Water cycle
C) Gas exchange
D) Soil formation
Answer: A
A food web is:
A) Single food chain
B) Network of food chains
C) Water system
D) Soil system
Answer: B
First trophic level consists of:
A) Carnivores
B) Producers
C) Decomposers
D) Herbivores
Answer: B
Second trophic level includes:
A) Producers
B) Herbivores
C) Carnivores
D) Decomposers
Answer: B
The 10% law was proposed by:
A) Darwin
B) Lindeman
C) Tansley
D) Odum
Answer: B
Energy decreases at each trophic level due to:
A) Growth
B) Respiration loss
C) Photosynthesis
D) Storage
Answer: B
Pyramid of energy is always:
A) Inverted
B) Upright
C) Circular
D) Linear
Answer: B
Pyramid of biomass can be inverted in:
A) Forest
B) Grassland
C) Aquatic ecosystem
D) Desert
Answer: C
Which ecosystem has highest productivity?
A) Desert
B) Forest
C) Tundra
D) Ocean
Answer: B
Ecosystem productivity is:
A) Rate of energy production
B) Rate of energy loss
C) Water usage
D) Soil formation
Answer: A
Gross primary productivity refers to:
A) Total energy fixed
B) Energy lost
C) Net energy
D) Stored energy
Answer: A
Net primary productivity equals:
A) GPP – respiration
B) GPP + respiration
C) Only respiration
D) Only consumption
Answer: A
Detritivores feed on:
A) Living plants
B) Dead organic matter
C) Animals
D) Soil
Answer: B
Ecological niche means:
A) Habitat only
B) Role of organism
C) Food chain
D) Climate
Answer: B
Habitat refers to:
A) Role
B) Place where organism lives
C) Food source
D) Energy source
Answer: B
A stable ecosystem is said to be in:
A) Chaos
B) Balance
C) Growth
D) Decline
Answer: B
Succession is:
A) Sudden change
B) Gradual change in ecosystem
C) Food chain
D) Climate change
Answer: B
Primary succession starts on:
A) Existing soil
B) Bare rock
C) Grassland
D) Forest
Answer: B
Secondary succession occurs after:
A) Volcanic eruption
B) Disturbance
C) Flood
D) Fire
Answer: B
Pioneer species are:
A) Last organisms
B) First colonizers
C) Decomposers
D) Carnivores
Answer: B
Climax community is:
A) First stage
B) Final stable stage
C) Temporary stage
D) Disturbed stage
Answer: B
Biome is:
A) Small ecosystem
B) Large ecological region
C) Organism
D) Habitat
Answer: B
Desert ecosystem has:
A) High rainfall
B) Low rainfall
C) Moderate rainfall
D) No rainfall
Answer: B
Grasslands are dominated by:
A) Trees
B) Grasses
C) Shrubs
D) Moss
Answer: B
Forest ecosystem is rich in:
A) Biodiversity
B) Water only
C) Soil only
D) Animals only
Answer: A
Aquatic ecosystems include:
A) Forest
B) Desert
C) Lakes
D) Grassland
Answer: C
Freshwater ecosystem includes:
A) Ocean
B) Sea
C) River
D) Estuary
Answer: C
Marine ecosystem includes:
A) Pond
B) Lake
C) Ocean
D) River
Answer: C
Estuaries are:
A) Freshwater bodies
B) Saltwater bodies
C) Mixing zones of fresh and salt water
D) Dry lands
Answer: C
Nutrient cycling includes:
A) Carbon cycle
B) Nitrogen cycle
C) Water cycle
D) All of these
Answer: D
Carbon cycle involves:
A) Oxygen only
B) Carbon exchange
C) Nitrogen
D) Hydrogen
Answer: B
Nitrogen fixation is done by:
A) Plants
B) Animals
C) Bacteria
D) Fungi
Answer: C
Water cycle involves:
A) Evaporation
B) Condensation
C) Precipitation
D) All of these
Answer: D
Biodiversity refers to:
A) Species variety
B) Only plants
C) Only animals
D) Only microbes
Answer: A
High biodiversity means:
A) Less stability
B) More stability
C) No stability
D) Temporary stability
Answer: B
Human activities affect ecosystems by:
A) Pollution
B) Deforestation
C) Urbanization
D) All of these
Answer: D
Ecological balance means:
A) No organisms
B) Stable interactions
C) Only plants
D) Only animals
Answer: B
Keystone species are:
A) Least important
B) Most influential
C) Producers
D) Consumers
Answer: B
50. Ecosystem services include:
A) Food
B) Clean air
C) Water purification
D) All of these
Answer: D