Functioning Ecosystems Questions

Objective Questions

What is the primary source of energy in an ecosystem?

A) Plants B) Soil C) Sun D) Water

Correct Answer: C) Sun

What is an ecosystem?

A) A group of plants living together B) A fundamental unit consisting of living organisms and their environment C) A collection of food chains D) A region with a specific climate

Correct Answer: B) A fundamental unit consisting of living organisms and their environment

Decomposers break down organic matter into:

A) Proteins B) Carbohydrates C) Soluble inorganic compounds D) Lipids

Correct Answer: C) Soluble inorganic compounds

Which of the following is an example of a macro-decomposer?

A) Bacteria B) Mushrooms C) Algae D) Protozoa

Correct Answer: B) Mushrooms

Decomposers help maintain ecosystem balance by:

A) Preventing herbivores from overgrazing B) Returning nutrients to the environment C) Storing energy from the sun D) Absorbing water from dead organisms

Correct Answer: B) Returning nutrients to the environment

What is the main function of micro-decomposers like bacteria and fungi?

A) Fixing nitrogen into plants B) Breaking down complex organic matter C) Absorbing carbon dioxide D) Providing food for carnivores

Correct Answer: B) Breaking down complex organic matter

What is an autotroph?

A) A primary consumer B) A producer that makes its own food C) A decomposer D) An omnivore

Correct Answer: B) A producer that makes its own food

Which of the following is a primary consumer?

A) Snake B) Grasshopper C) Hawk D) Mushroom

Correct Answer: B) Grasshopper

Secondary consumers primarily feed on:

A) Decomposers B) Primary consumers C) Plants D) Soil nutrients

Correct Answer: B) Primary consumers

In a food web, which of these organisms is a tertiary consumer?

A) Grasshopper B) Frog C) Hawk D) Earthworm

Correct Answer: C) Hawk

Which of these represents a correct food chain?

A) Grass → Rabbit → Hawk → Snake B) Grass → Grasshopper → Frog → Snake C) Grasshopper → Snake → Grass → Frog D) Rabbit → Grass → Snake → Hawk

Correct Answer: B) Grass → Grasshopper → Frog → Snake

What percentage of energy is typically transferred from one trophic level to the next?

A) 90% B) 50% C) 25% D) 10%

Correct Answer: D) 10%

Why does energy decrease as it moves up the trophic levels?

A) Energy is destroyed B) Energy is lost as heat and through metabolic activities C) Energy is transferred back to producers D) Organisms at higher levels store all the energy

Correct Answer: B) Energy is lost as heat and through metabolic activities

The Pyramid of Numbers represents:

A) Total biomass at each trophic level B) Number of organisms at each trophic level C) Energy flow in an ecosystem D) The amount of oxygen produced

Correct Answer: B) Number of organisms at each trophic level

The Pyramid of Biomass shows:

A) The total weight of living organisms at each trophic level B) The number of organisms at each level C) The energy produced by autotrophs D) The total number of species in an ecosystem

Correct Answer: A) The total weight of living organisms at each trophic level

The Pyramid of Energy is always:

A) Inverted B) Upright C) Circular D) Linear

Correct Answer: B) Upright

The First Law of Thermodynamics states that:

A) Energy can be created and destroyed B) Energy cannot be created or destroyed, only transformed C) Energy is constantly lost in an ecosystem D) Producers absorb more energy than they need

Correct Answer: B) Energy cannot be created or destroyed, only transformed

The Second Law of Thermodynamics explains:

A) Energy transfer between organisms is always efficient B) No energy is lost in a food chain C) Some energy is lost as heat at each trophic level D) All energy is passed from producers to consumers

Correct Answer: C) Some energy is lost as heat at each trophic level

Why are food chains usually limited to 3-5 trophic levels?

A) Energy is used up by decomposers B) The sun provides less energy at higher levels C) There is insufficient energy to sustain more levels D) Consumers at higher levels grow too large

Correct Answer: C) There is insufficient energy to sustain more levels

What happens to energy not transferred to the next trophic level?

A) It disappears B) It is converted into new organisms C) It is lost as heat and metabolic waste D) It is stored in producers

Correct Answer: C) It is lost as heat and metabolic waste

Theory Questions

State the various ways energy is lost in an ecosystem

Briefly explain why a food chain is never longer than 5 trophic levels

Explain the following terms; Autotrophs, Heterotrophs and Decomposers.

What is a “Food chain”?

State two characteristics of decomposers