Build a labelled energy-flow pathway
A clear pathway labels each energy form and points arrows in the direction of transfer.
Mapped to the named 0654 section using teaching from the corresponding single-science course. A 0654-specific review of every Core and Supplement objective is still in progress. Written practice is self-checked; it does not demonstrate supervised laboratory competence or award an official Cambridge grade.
Before you begin
- Food chains are addressed in 19.2; this drawing practises the energy labels required for 19.1.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
What three kinds of label make a basic energy-flow diagram clear?
What you will learn
- Construct a simple energy-flow route through organisms
- Label light, chemical energy and transfer to the environment
Original qualitative energy-flow schematic; arrows show direction, not measured amounts.
Construct the route in stages
Begin with the incoming light energy from the Sun. Show a photosynthetic organism absorbing some light and storing energy as chemical energy in organic material. If a consumer feeds, continue the route with chemical energy transferring in food material to that organism.
Add an outward arrow to show energy eventually transferring to the environment. Label the form or process when known, such as heat transferred during respiration. Keep the arrow direction consistent with the transfer.
Make the diagram answer the question
A diagram about organisms may use organism names, while a diagram about energy should also label energy forms. A chain of names alone can show feeding order but not fully describe the requested energy flow.
Do not add a closed arrow from the environment back to the Sun. New sunlight is an input; energy that reaches the environment is not the same energy returning unchanged to the original input.
Sources for this lesson
Pause and explain
Which pathway best represents light entering grass and then reaching a rabbit?
Worked example
Construct an energy pathway for sunlight entering grass, a rabbit eating the grass and energy eventually reaching the surroundings.
Show the worked solution
- Start with Sunlight → grass.
- Label chemical energy in grass, transfer by feeding to rabbit, then an outward transfer to the environment.
Answer Sunlight (light energy) → grass (chemical energy in organic material) → rabbit (chemical energy transferred by feeding) → environment (eventual transfer, including heat).
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.
Write a labelled energy pathway from sunlight to a leaf-eating insect, then to the environment.
Give me a hint
Show light input, chemical store, feeding and outward transfer.
Compare my reasoning
- Sunlight supplies light energy to the plant.
- Chemical energy in the leaf transfers to the insect; some energy later transfers to the environment.
Sunlight (light energy) → plant leaf (chemical energy in organic material) → insect by feeding (chemical energy transfer) → environment (eventual transfer, for example as heat).
Look for these in your work
- Incoming form
- Feeding and environment arrows
A food diagram reads “oak → caterpillar → bird.” Add two energy labels that make the energy transfer explicit.
Give me a hint
Add the incoming and feeding forms.
Compare my reasoning
- Show light energy from the Sun entering the oak.
- Label chemical energy in oak material transferred to caterpillar, then in caterpillar material transferred to bird.
Add sunlight (light energy) → oak, and label the feeding arrows as chemical energy in organic material transferring to each consumer.
Look for these in your work
- Sunlight input
- Chemical transfers
A student draws plant → deer → environment, with every arrow labelled “energy”. Improve the model without inventing quantities.
Give me a hint
Name energy forms, direction and endpoint.
Compare my reasoning
- Identify light energy entering the plant and chemical energy stored in organic material.
- Label feeding transfer and an eventual outward transfer such as heat to the environment.
Show Sunlight (light energy) → plant (chemical energy in organic material) → deer by feeding (chemical energy transfer) → environment (eventual transfer, including heat). No quantity is supplied.
Look for these in your work
- Energy forms added
- No false numbers
Common mistakes
- Drawing only organisms and omitting energy forms
- Using arrows without direction or labels
- Adding a return arrow that makes energy look cyclic
What can you explain now?
What three kinds of label make a basic energy-flow diagram clear?
Compare with the explanation
Energy form, organism or store, and transfer direction
These show where energy is and how it moves.
After trying it yourself, choose your next review. This is your self-assessment.
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Make it stick
Construct a simple labelled energy route from sunlight through a producer and consumer to the environment.
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.