Module F Review: Energy in Ecosystems

Which of the following best defines a trophic level in an ecosystem?

• The amount of sunlight an area receives

• The position an organism occupies in a food chain

• The number of species in an ecosystem

• The rate at which plants grow

What is the primary source of energy for most ecosystems?

• Wind

• Sunlight

• Water

• Soil

Which organisms are considered producers in a food web?

• Herbivores

• Carnivores

• Plants and algae

• Decomposers

What term describes animals that eat only plants?

• Omnivores

• Herbivores

• Carnivores

• Decomposers

Which of the following best describes the flow of energy through trophic levels?

• Energy increases at higher trophic levels

• Energy is recycled and never lost

• Energy decreases as it moves up trophic levels

• Energy remains constant at all levels

If a food chain is grass → grasshopper → frog → snake, which organism is the secondary consumer?

• Grass

• Grasshopper

• Frog

• Snake

Which statement best explains why there are usually fewer top predators than primary consumers in an ecosystem?

• Top predators reproduce faster

• Energy is lost at each trophic level

• Top predators eat only plants

• Primary consumers are less important

If 10,000 J of energy is available at the producer level, and only 10% of energy is transferred to the next trophic level, how much energy is available to primary consumers?

• 1,000 J

• 100 J

• 10 J

• 10,000 J

A food chain is: phytoplankton → zooplankton → small fish → large fish → eagle. If the eagle receives 1 kcal of energy, how much energy was present at the phytoplankton level, assuming 10% energy transfer at each step?

• 10 kcal

• 100 kcal

• 1,000 kcal

• 10,000 kcal

Analyze the following scenario: In a grassland ecosystem, a disease wipes out most of the primary consumers. Predict and explain the likely impact on producers and secondary consumers.

• Producers decrease, secondary consumers increase

• Producers increase, secondary consumers decrease

• Both producers and secondary consumers increase

• No change in either group