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Ecology and Ecosystems: Question 1

Syllabus 19.2

Multiple choice Core 1 mark

A tropical pitcher plant has ordinary green leaves that photosynthesise like any other plant. Some of its leaves are also modified into pitcher-shaped traps. Insects are lured inside the pitchers, drown in a pool of digestive fluid, and are broken down. The plant absorbs minerals released from the digested insects, but photosynthesis remains its main source of energy.

Which term correctly describes the pitcher plant's role in a food web, and why?

Choose an answer to check it, then compare with the worked solution below.
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Worked solution

Step 1: Recall the definitions of producer and consumer

A producer is an organism that makes its own organic nutrients, usually using energy from sunlight, through photosynthesis. A consumer is an organism that gets its energy by feeding on other organisms. A decomposer gets its energy from dead or waste organic material.

The key distinction is about energy source, not simply about what an organism does with other living things.

Step 2: Apply this to the pitcher plant

The pitcher plant’s green leaves photosynthesise, so it is already making its own organic nutrients using light energy, exactly like any other plant. The insects trapped in its pitchers are digested and provide extra minerals, not the plant’s main supply of energy. Because photosynthesis remains its main energy source, the pitcher plant is classified as a producer, even though it also captures and digests insects.

Why the other options are wrong

  • A (primary consumer): trapping and digesting insects does not make the plant a consumer, because its energy still comes from photosynthesis, not from feeding.
  • B (decomposer): a decomposer’s energy comes from feeding on dead or waste material; here, the digested insects supply minerals, and the plant’s energy still comes from photosynthesis.
  • D (secondary consumer): this wrongly focuses on what the trapped insects have eaten, rather than on how the pitcher plant itself obtains its energy.

Final answer

The pitcher plant is a producer, because it makes its own organic nutrients by photosynthesis and this remains its energy source, option C.