Build a food chain and read its arrows
A food chain is a simple model of energy transfer from one organism to the next, beginning with a producer.
Core and Extended; Biology 0610, 2026–2028. Use the stated specimen features and evidence. Diagrams are schematic. Written practice is self-checked
Before you begin
- Read energy-transfer arrows and distinguish energy from matter in the 19.1 Energy flow pathway.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
In a food chain, what does an arrow show?
What you will learn
- Construct a simple food chain from feeding evidence
- Interpret arrow direction as the direction of energy transfer
Read the chain from producer to consumer
A food chain models feeding links and energy transfer. Begin with a producer, then list the organism that eats it, followed by the next consumer. In a grassland, grass → grasshopper → frog → snake is one possible chain. Each arrow points from the organism eaten to the organism receiving energy.
An arrow does not mean “is eaten by” when read in the arrow direction. It means that energy is transferred from the first organism to the next when feeding occurs. Add only links supported by the stated habitat or evidence; a possible chain is not a complete description of every interaction.
Construct before interpreting
Use the evidence to identify who eats what, then draw one arrow for each feeding link. Check that the chain starts with a producer and that every arrow points towards the consumer. If a question asks what happens when one population changes, trace the arrows one link at a time before suggesting an indirect effect.
A food chain is a simplified pathway. It does not show every organism’s food source, and it does not show that the same amount of energy is passed at each step. Food webs and ecological pyramids add other kinds of information.
Pause and explain
Given algae are eaten by insect larvae and larvae by fish, which chain is correctly drawn?
Worked example
A record says that a caterpillar eats cabbage leaves and a small bird eats caterpillars. Construct the chain and state what its arrows mean.
Show the worked solution
- Place the plant producer first: cabbage plant.
- Add the eater of the plant, then the eater of that animal.
- Point each arrow from food organism to consumer.
Answer Cabbage plant → caterpillar → small bird. Each arrow shows the direction of energy transfer during feeding, from the organism eaten to the organism receiving energy.
Try a topic test
Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.
Test this topic →From guided practice to a new situation
Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
A pond survey says waterweed is eaten by snails and snails are eaten by perch. Draw and label the chain.
Give me a hint
Begin with the producer and point arrows towards each consumer.
Compare my reasoning
- Waterweed is the producer named in the record.
- Snails eat waterweed; perch eat snails.
- Draw waterweed → snails → perch.
Waterweed → snails → perch. The arrows show energy transfer from the food organism to the organism that eats it.
Look for these in your work
- Producer first
- Both arrows point to consumers
A learner writes “fox → rabbit” after reading “foxes eat rabbits”. Correct the chain and explain.
Give me a hint
Translate “eats” into an arrow from food to eater.
Compare my reasoning
- The rabbit is the organism eaten.
- The fox receives energy by eating the rabbit.
Write rabbit → fox. The original arrow was reversed because the energy-transfer arrow points from food to consumer.
Look for these in your work
- Direction corrected
- Meaning explained
A field note shows hawks eating mice and mice eating seeds. Construct this chain, then name one thing it does not tell you.
Give me a hint
Use only the recorded links; avoid treating the chain as a whole web.
Compare my reasoning
- Seeds → mice → hawks.
- The record gives one feeding route, not every diet or interaction in the field.
Seeds → mice → hawks. This chain does not show all organisms eaten by mice or all prey eaten by hawks.
Look for these in your work
- Chain is supported
- Model limitation stated
Common mistakes
- Pointing arrows from predator to prey
- Starting every chain with an animal
- Assuming a chain shows all feeding links
What can you explain now?
In a food chain, what does an arrow show?
Compare with the explanation
Energy transfer from the organism eaten to its consumer
The arrow follows the feeding link towards the consumer.
After trying it yourself, choose your next review. This is your self-assessment.
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Make it stick
Starting with a producer, explain how you would turn two “eats” statements into a correctly directed food chain.
If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.