Recap that an ecosystem has living and non-living parts that depend on one another. Introduce the big idea: all the energy in an ecosystem starts with the Sun.
Using the slide deck, model a simple food chain: Sun → grass → rock wallaby → wedge-tailed eagle. Draw the arrows one at a time, thinking aloud: "The grass uses the Sun's energy to make food — it's a producer. The rock wallaby eats the grass, so I draw the arrow from the grass to the wallaby, because the energy moves that way. The wallaby is a consumer." Stress the rule: the arrow points to the living thing doing the eating.
In small groups, students build a paper-chain food chain — each link is one living thing in the chain. Distribute picture cards of living things from a local Australian ecosystem. Groups arrange them into a sensible chain, then make the paper chain.
Each group shares its chain; the class gives feedback and groups edit (adding or removing links) so every chain: (1) starts with a producer, (2) keeps all living things in the same habitat, and (3) has arrows/links in the right order. Hold a quick hands-up vote — "Are humans producers or consumers?" — and draw out the reasoning.
Students complete the Building Food Chains worksheet: filling the vocabulary blanks, fixing arrow directions on a given chain, deciding whether humans are producers or consumers with a reason, and designing their own three-step food chain from one habitat with correctly directed arrows and labelled roles.
Collect the edited paper chains to reuse in Lesson 3, where they will be joined into a food web.