The completed activity has five directed links and three routes from producer P to large consumer L. Removing grazer G leaves two links and one route, P→S→L. Students can check each connection as they build, then use the changed web to explain exactly what remains connected.
Start with the feeding cards
Use four fictional roles: P is a producer, G a grazer, S a small consumer, and L a large consumer. P uses an external energy source in this model; it does not create energy. The letters keep attention on the supplied relationships. They are not real species or a claim that body size determines diet.
Give students these five statements before showing the answer key:
| Feeding card | Correct energy arrow |
|---|---|
| G eats P | P→G |
| S eats P | P→S |
| S eats G | G→S |
| L eats G | G→L |
| L eats S | S→L |
For a paper version, cover the right column and draw four labeled circles. For the interactive version, each card offers two arrow directions. A correct choice adds its link to the diagram and the text list. A reversed choice gives a clue and leaves the web unchanged.
Ask partners to finish this sentence before choosing: “The food is __, so energy moves toward __.” For “S eats G,” the blanks are G and S. NOAA's aquatic food webs explanation uses the same prey-to-predator direction for energy arrows.
Build five links, then find every route
Count distinct arrows after all five cards are complete. Selecting the same answer again cannot create another link. The finished set is P→G, P→S, G→S, G→L, and S→L.
Now have students trace from P to L, following arrowheads at every step. There are three routes: P→G→L, P→S→L, and P→G→S→L. The last route is easy to miss because it travels through both middle nodes. Enter 3 in the route-count box and check the answer to reveal the complete list.
An indirect route does not add a direct feeding link. P→L is absent because none of the cards says “L eats P.” Ask a student proposing that shortcut to identify its feeding card. Without one, the shortcut stays off the diagram, even though energy can travel from P to L through other nodes.
Remove G and explain the change
Before pressing “Remove G,” ask students to write down every arrow touching G. The three affected arrows are P→G, G→S, and G→L. Removing G deletes those connections together. P→S and S→L remain, so the changed web still contains P→S→L.
Use the remaining route as an exit question: “What can this web tell us about L?” A supported answer is that L still has a route from P through S in this model. A claim that L's population will stay constant, increase, or disappear goes beyond the supplied information. There are no population counts, feeding rates, or energy amounts to calculate from.
The activity keeps the completed feeding-card answers visible while showing the smaller network. Reset starts a fresh attempt with four nodes and no student links. Answers last only while the page remains open; use students' written explanations if you need a class record.
Copy a prompt for your activity
Create a complete US-English food-web classroom activity as one self-contained HTML file. Use four fictional nodes: P producer, G grazer, S small consumer, L large consumer. P uses an external energy source; do not say it creates energy. Display these five feeding cards: G eats P; S eats P; S eats G; L eats G; L eats S.
Start with four labeled nodes and no learner links. For each feeding card, provide two accessible buttons offering the correct food-to-consumer arrow and its reverse. The correct set is P→G, P→S, G→S, G→L, S→L. Correct choices add a unique arrow to the diagram and a readable text list; reversed choices explain which node supplies food and allow another attempt. Keep completed answers visible. Do not add P→L.
After all five cards are correct, let learners enter the number of P-to-L routes. Check their answer against 3 and show all routes: P→G→L, P→S→L, P→G→S→L. Include a Remove G button that deletes P→G, G→S, G→L and leaves P→S, S→L, with the remaining route P→S→L. Preserve the original feeding-card answers for comparison. Reset restores four nodes and clears the attempt.
Use a warm paper background, dark readable text, a prominent arrow-direction reminder, and a responsive diagram beside the cards. Stack sections on narrow screens, with readable text and generous button spacing. Use click handlers and type="button" controls so the game works inside a scripts-only iframe. Include a teacher key and an exit question distinguishing connectivity from population predictions. Use no external libraries, network requests, saved grades, or download promises. Return the finished HTML.
Before the next lesson, try a reversed arrow and the Remove G round yourself, then choose which explanation you want students to write. If you use NOS to view the prepared HTML activity, its HTML preview lets you inspect the cards and diagram before class. Keep the five feeding statements beside the screen so students can justify each arrow from the evidence.