Reading Food Web Diagrams
Read and interpret food web diagrams — identify producers, primary and secondary consumers, and decomposers; trace energy flow along food chains within the web; predict the effect of removing or adding a species
What a learner can do afterwards
- Identify the producer, herbivore, and carnivore in a food web from a diagram
- Trace two food chains through the same food web and identify shared species
- Predict what would happen to fox numbers if rabbits were removed from a food web diagram
The lesson
You've read diagrams with arrows before, like circuit diagrams. A food web is a diagram too, but its arrows mean something different: they show who eats whom. Each arrow points from the food to the animal that eats it.
Every food web has roles. The producer makes its own food, like the plant. The herbivore eats only plants, like the insect. A carnivore eats other animals, like the frog and the hawk. There are also decomposers, like worms and mushrooms, that break down dead plants and animals.
A food web is more than one chain. In this web, the insect is eaten by the frog, but the hawk eats the insect too, directly. So the insect is shared by two food chains: Plant to Insect to Frog to Hawk, and Plant to Insect to Hawk.
To predict what happens if an animal disappears, ask two questions: what did it eat, and who ate it? If frogs vanished, insects would have one less predator, and the hawk would need to rely more on eating insects directly.
Arrows in a food web point from food to eater, and tracing every chain that connects to a species tells you what happens if it disappears.
Watch it
Where it sits
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Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.