Practice - 1.4 Food Chains and Food Webs: Tracing Energy Flow
Practice Questions
Test your understanding with targeted questions
In a food chain, what do the arrows represent?
* Answer: The direction of energy flow.
* Hint: Where does the energy go?
💡 Hint: Where does the energy go?
What is the trophic level of a producer?
* Answer: Level 1.
* Hint: They are at the very beginning of the energy path.
💡 Hint: They are at the very beginning of the energy path.
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Interactive Quizzes
Quick quizzes to reinforce your learning
A Hawk eats a Snake, and the Snake eats a Frog. The Frog eats a Grasshopper. Which organism is the Secondary Consumer?
* Type: mcq
* Options: Grasshopper, Frog, Snake, Hawk
* Correct Answer: Frog
* Explanation: The grasshopper is primary (eats producer), the frog is secondary (eats grasshopper), and the snake is tertiary (eats frog).
* Hint: Follow the chain: Producer → Grasshopper (1st) → Frog (2nd) → Snake (3rd).
💡 Hint: Follow the chain: Producer → Grasshopper (1st) → Frog (2nd) → Snake (3rd).
True or False: A food web shows only one pathway of energy flow in an ecosystem.
* Type: boolean
* Options: True, False
* Correct Answer: False
* Explanation: A food web shows many interconnected pathways and multiple feeding relationships.
💡 Hint: No hint provided
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Challenge Problems
Push your limits with advanced challenges
A small lake ecosystem consists of algae, zooplankton, small fish, and kingfishers.
* a) Draw a food chain for this lake and label each trophic level.
* b) If the algae population crashes due to pollution, explain the immediate and long-term consequences for the other levels.
* c) How might a diverse food web buffer the ecosystem against this crash?
* Solution:
* a) Algae (Producer) → Zooplankton (Primary Consumer) → Small Fish (Secondary Consumer) → Kingfisher (Tertiary Consumer).
* b) Immediate: Zooplankton starve. Long-term: Small fish and then kingfishers decline as the food shortage cascades up the chain.
* c) Alternative food sources (e.g., small fish eating insect larvae) provide more pathways for energy, making the ecosystem more resilient and less dependent on a single producer.
💡 Hint: No hint provided
Why is protecting a large area crucial for sustaining top predators like wolves or cougars?
* Solution: According to the 10% rule, energy is lost at every level. A single top predator requires a massive biomass base of prey (secondary and primary consumers), which in turn requires an even larger base of producers. A small habitat cannot support enough lower-level biomass to provide the necessary energy for a viable population of apex predators. Large, contiguous habitats ensure the sustainability of the entire food web.
* Hint: Think about the base of the energy pyramid. If the top needs a lot, what does the bottom need?
💡 Hint: Think about the base of the energy pyramid. If the top needs a lot, what does the bottom need?
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