Write the word ecosystem on the board and invite students to share what comes to mind. Then give the working definition: an ecosystem is all the living and non-living things in an area that depend on one another.
Model the living / non-living distinction with a few objects from the room, thinking aloud: "A pot plant grows, needs water and light, and can make more plants — so it's living. The pot is non-living, but the plant needs it to hold soil." Emphasise that ecosystems need both living and non-living parts (sun, water, soil, rocks, air).
Take the class on a short schoolground walk. Students carry clipboards and record everything they see — grass, trees, insects, birds, people, playground equipment, taps, soil. Back inside, build a class chart, sorting the observations into living and non-living together.
Then pose "what if" questions to reveal interdependence, taking a few responses each:
- How would our schoolyard change if there were no water?
- What would happen to the birds if all the trees were removed?
- Which living things depend on the non-living things we listed?
Students complete the Ecosystem Explorer worksheet: they use the Living or Non-Living? sorting cards to classify a set of items, then choose a habitat and list its living and non-living parts, and answer a short "what would happen if…" prompt in their own words.
Finish with the exit ticket: "An ecosystem is…" completed in the student's own words, collected as a quick check of understanding.