Lesson 3: Food Chains & Interconnected Food Webs in NZ Native Bush
Exploring NZ ecosystems, biodiversity, energy flow, invasive pests, kaitiakitanga, and field restoration projects.
🎯 Ngā Whāinga Akoranga | Learning Intentions
Food chains vs food webs, arrows indicating energy flow direction, interdependency between species, and cascade effects when a key species is removed.
Construct a complex NZ native forest food web linking honeydew, bellbirds, kererū, invertebrates, and falcons, and predict ripple effects of species removal.
🎥 Media Anchor & Pedagogical Scaffold
Food Webs & Trophic Cascades in Forest Ecosystems
Video Clip: Energy flow in food chains & webs — Khan Academy (Watch in full — declared full-watch).
🧠 1. Before Viewing (Activate & Predict)
What do the arrows in a food web diagram actually represent, and why are food webs more realistic than food chains?
👁️ 2. During Viewing (Watch With a Job)
- As you watch: Which direction do food web arrows point — from eater to food, or from food to eater? What does the arrow represent?
- Note: How are food webs more realistic than simple food chains? What happens when one species is removed?
- Apply to Aotearoa: Think about a NZ beech forest — scale insects → honeydew → tūī/kākā. How would a trophic cascade unfold if bird numbers collapsed?
🗣️ 3. After Viewing & Kaiako Move (Process & Apply)
Kaiako Move: Facilitate a 'Yarn Web of Life' activity where students hold string connections; dropping one string pulls down connected partners.
Immediate Task: Complete Section 3 of your Ecology Field Journal: NZ Bush Food Web Diagram & Cascade Prediction Log.
⚡ Whakaoho | Do Now: Pyramid From Memory (10 mins)
Without opening your journal, sketch last lesson's energy pyramid: producer → primary consumer → secondary consumer, with one NZ native example at each level. Then answer underneath: if the producers halved, what happens at the top — and why does the effect get worse the higher you go? Check against Section 2 when you finish.
📖 Activity 1: Yarn Web of Life — Beech Forest (25 mins)
- Cards out (5 min): each person takes a beech-forest species card: beech tree, scale insect (honeydew), tūī, kākā, bellbird/korimako, kererū, wētā, pīwakawaka, kārearea, fungi/decomposers — plus rat and stoat cards held back for step 3.
- Build the web (10 min): stand in a circle. Pass the ball of yarn from each species to something it eats or feeds, saying the link aloud ("I am the scale insect — I feed on beech sap"). Keep passing until everyone holds at least two strands.
- Break the web (5 min): kaiako removes one species — that person tugs their strands. Everyone who feels a tug raises a hand: count the ripple. Rebuild, then introduce the rat and stoat cards and watch where their strands attach. Remove the birds this time — count again.
- Record (5 min): at desks, draw the web you just built with arrows showing the direction energy flows (from eaten to eater).
📝 Activity 2: Field Journal Section 3 — Food Web & Cascade Prediction (20 mins)
Write up Section 3 of your Ecology Field Journal: your NZ bush food web diagram with correctly-directed arrows, then a cascade prediction — choose one species, remove it on paper, and trace every knock-on effect through at least three other species. Use food web, trophic cascade and interdependence correctly, and finish with the yarn-circle evidence: which removal caused the biggest ripple, and what does that say about which species this forest can least afford to lose?
🏫 Kaiako Planning & Pedagogy Notes
Prep: species cards (write them on card in two minutes if needed) and a ball of yarn. Run the removal twice — a bird collapse and a decomposer collapse — so ākonga see that ripple size depends on how connected a species is, not how big it is. Leave the yarn web on the floor while they sketch; it is the diagram. Curriculum anchoring for the unit sits on the unit page (verbatim Te Mātaiaho statements).