LightMySky

Ocean Food Webs

Understand ocean food webs: multiple interconnected food chains where energy flows from phytoplankton (producers) through zooplankton, small fish, and large predators, and that removing one species affects the whole web

No account needed. Progress saves in this browser.

What a learner can do afterwards

  • Distinguish a food web from a simple food chain
  • Trace at least two paths of energy through an ocean food web
  • Explain what could happen if one species in the web were removed

The lesson

You already know a food chain: one line where energy moves from one living thing to the next, like algae to a small fish to a big fish. In the real ocean, most animals eat more than one kind of food, and get eaten by more than one kind of animal. Connect all those chains together and you get a food web.

AlgaeZooplanktonSmall fishTuna
One path through the web: algae make food from sunlight, zooplankton eat the algae, small fish eat the zooplankton, and tuna eat the small fish.
Try it together

Mia looks at the same food web and finds a second path. This time, small fish get eaten by a shark instead of a tuna. Both paths start at the algae, but they end differently. That crossing is what makes it a web instead of a single chain.

AlgaeSmall fishShark
Good to know

If people catch too many small fish, tuna and sharks lose part of their food, and zooplankton have fewer hunters, so their numbers can grow too fast. Removing just one kind of animal can shift the whole web, not only its own chain.

A food web links many ocean food chains together, so changing one species can change the whole web.

Watch it

Where it sits

Where this leads

Jobs that lean on this skill. Follow one to see everything it is built on.

Then practise

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.

Ocean Food Webs · Science, ages 7 to 9 · LightMySky