Distinguish producers from consumers
Producers make organic nutrients, usually by photosynthesis; consumers get energy by feeding on other organisms.
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
- 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
Which description best defines a producer?
What you will learn
- Describe the roles of producers and consumers
- Classify organisms using how they obtain organic nutrients and energy
Producers make organic nutrients
A producer makes its own organic nutrients. In most examples at this level, a green plant or alga uses light energy in photosynthesis to make organic molecules. It is called a producer because it makes material that can support feeding relationships, not because it produces energy from nothing.
Use “usually” when linking producers with sunlight and photosynthesis. A producer is defined by making its own organic nutrients; do not identify an organism as a producer solely because it is green or because it lives at the water surface.
Consumers feed on other organisms
A consumer obtains energy by feeding on other organisms. Consumers include animals that eat plants or other animals. In a chain, a consumer appears after the organism that supplies its food. One species can be a consumer at different levels in different feeding routes, especially when it eats more than one kind of organism.
Food provides both matter and chemical energy. In this section, use the feeding link to identify which organism is the producer and which is the consumer. Decomposers also obtain energy from organic material, but their role is considered separately.
Sources for this lesson
Pause and explain
In phytoplankton → krill → whale, which organism is the consumer that eats the producer?
Worked example
In a chain algae → zooplankton → small fish, identify the producer and two consumers.
Show the worked solution
- Algae make organic nutrients by photosynthesis.
- Zooplankton feed on algae; the fish feed on zooplankton.
Answer Algae is the producer. Zooplankton and the small fish are consumers.
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 diagram shows grass making organic material and a rabbit eating it. Identify both roles and justify them.
Give me a hint
Base roles on how each obtains organic nutrients.
Compare my reasoning
- Grass makes organic nutrients, usually by photosynthesis.
- The rabbit gets energy by feeding on the grass.
Grass is the producer because it makes its own organic nutrients; the rabbit is a consumer because it obtains energy by feeding on the grass.
Look for these in your work
- Producer role linked to making nutrients
- Consumer role linked to feeding
A learner says “a tree produces energy for a squirrel.” Rewrite the sentence precisely.
Give me a hint
Separate energy transfer from the producer’s role.
Compare my reasoning
- The tree makes organic nutrients by photosynthesis.
- The squirrel obtains chemical energy by feeding on material from the tree.
The tree makes organic nutrients, usually using light energy in photosynthesis; the squirrel gets energy by feeding on organic material from the tree.
Look for these in your work
- Organic nutrients described
- No claim that energy is created
A pond producer is an alga that is eaten by insect larvae. Which organism makes its own organic nutrients, and which feeds on another organism?
Give me a hint
Apply the definitions to the stated feeding link.
Compare my reasoning
- The alga makes its own organic nutrients.
- The larvae feed on the alga.
The alga is the producer; the insect larvae are consumers.
Look for these in your work
- Correct role assigned to each
- Evidence used
Common mistakes
- Calling a producer an organism that creates energy
- Defining a consumer only as an animal
- Ignoring that producers usually, rather than invariably, use sunlight
What can you explain now?
Which description best defines a producer?
Compare with the explanation
An organism that makes its own organic nutrients, usually by photosynthesis
This describes how producers supply organic material to food chains.
After trying it yourself, choose your next review. This is your self-assessment.
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Make it stick
Define producer and consumer, and explain why “producer creates energy” is not an accurate description.
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.