Students use a magnifying glass to explore the decomposition of leaf litter. Students will observe fungi (the primary consumer) initiating the decomposition process.

Learning objective

Students understand the process of decomposition and how composting is an accelerated form of this natural process.

Curriculum links

Chemical sciences

Nature and development of science
Use and influence of science

Cross-curriculum priority: Sustainability

Decomposition, primary/secondary/tertiary consumers, carbon cycle, food web


This lesson explores decomposition within leaf litter and how decomposers are part of the food web.

All living things will eventually die but this is just the beginning, as the decay and decomposition (rot) which follows provides material for other new life.

When an organism dies, bacteria and fungi both work to break down the organism. This is called decomposition.

There are thousands of types of bacteria and single-celled fungi that live in the soil, while other decomposers live in the guts of dead animals or in the leaves.

Insects, worms and other invertebrates will join in with the decomposition process after the bacteria and fungi have kicked things off.

“Life would end without rot,” observes ecologist Knute Nadelhoffer.  “Decomposition releases the chemicals that are critical for life. Decomposers mine them from the dead so that these recycled materials can feed the living.”

Carbon is the most important element recycled by decomposition. Following death, carbon is released into the air, soil and water through the decomposition process. Living things capture this liberated carbon to build new life. Scientists call this the carbon cycle.

An area containing leaf litter/twigs/branches decomposing (a shaded wet area will provide the best conditions).

Magnifying glass and/or magnifying loupe glass (one per student).

A tray to place and observe decomposing material.

Access to the internet to show a short video.

In the activity area:

  • Instruct students to gently remove the top layer of leaf litter using their fingers to expose the damper litter beneath.
  • A sample of the leaf litter can be placed in the tray for closer observation.


  • Can you observe evidence of decomposition within the leaf litter and on any twigs and/or branches?
  • Can you identify any of the decomposers from the ‘Food web of the compost heap’ image?

Encourage students to compare the surface leaf litter (not yet decomposing) with that buried beneath, as decomposition will then be easier to identify. Evidence may include rotting leaf litter, twigs and branches, and fungi. Partially buried twigs and branches are more likely to have fungal hyphae growing on them.

Please refer to Figure 1 (where gradual leaf decomposition can be identified) and Figure 2 (of fungal hyphae growing on a decomposing branch).