Ecology · Make

A food web with labelled assumptions

How do arrows and evidence change the meaning of a simple food web?

Build a food-web diagram from supplied fictional feeding records and keep a proposed link different from a reported one.

15–25 minutes, or one chain for a first try. More time is optional.

Five solid arrows run from Plant to Leaf-eater and Snail, then to Lizard and from Lizard to Bird. A dashed Snail-to-Bird link is labelled not supplied.
Constructed food web: five reported links. Open full-size diagram ↗

Start here

Use these invented records: Plant feeds Leaf-eater and Snail; Leaf-eater and Snail feed Lizard; Lizard feeds Bird. Arrows point from food to consumer.

Use your idea or the example below. Talk, write, draw, point or listen first. You can stop after one step.

Try it your way.

  1. Write the arrow key

    An arrow A → B means material and energy from A can reach B when B consumes A. It does not mean A actively helps or chases B.

  2. Draw five supplied links

    Draw Plant → Leaf-eater, Plant → Snail, Leaf-eater → Lizard, Snail → Lizard and Lizard → Bird. Keep every direction consistent with the key.

  3. Label a new question

    Someone proposes that Bird also consumes Snail. Draw that optional idea as a dashed link labelled ‘not supplied’, rather than adding it to the five solid recorded links.

  4. Explain what the model leaves open

    Name a missing detail such as quantities, seasonal change or other foods. The web does not tell you exactly how any population would change.

One possible version

Constructed food web: five reported links

The feeding statements are invented model records, not observations of real animals or universal species diets.

  • Solid links: Plant → Leaf-eater; Plant → Snail; Leaf-eater → Lizard; Snail → Lizard; Lizard → Bird.
  • Each arrow runs from the consumed resource to its consumer.
  • Snail → Bird is a separate proposed link, shown dashed and marked not supplied.

The model omits amounts and many relationships. It does not establish actual diets, complete energy budgets or a definite population outcome.

A different way.

Follow only Plant → Snail → Lizard, or read the links aloud. No animals, food, samples or outdoor visit are required.

If you want more.

Remove one supplied link in a newly labelled model. Describe which route disappears without asserting a measured population change.

Something to keep?

Could someone distinguish a supplied relationship from a proposed one in my drawing?

You can keep a question, a sketch or a change of mind. A finished product is optional.

This opens an editable starter in your project tools. It asks before replacing open work. Choosing it does not save or share your work automatically.

← Choose another activityBring your own idea ↗