A class stacks a tower, pulls labelled blocks as species disappear, and watches it sway: that is the biodiversity jenga activity in a single sitting, with a debrief to follow.
Quick answer: write a species name on every block, build the tower, and let students remove blocks as species are lost. Give a few blocks keystone rules, stop when the tower falls or a clear pattern appears, then run the debrief below. For wider lesson planning, see our guide to teaching biodiversity to students.
Before you start: goal, materials and standards
This activity suits middle school classes that already know what a food web is. The outcome is a shared, visible model in which students see that removing species can weaken an ecosystem, and then discuss why the model is imperfect. NSTA’s Science Scope describes a modified version of the Jenga game as a hands-on, inquiry-based model of a balanced ecosystem, and the protocol here follows that idea.
You need a Jenga set for each group, permanent markers or small labels, a species list for one ecosystem, and a recording sheet. Choose a Maine habitat your students know, such as a pond, a forest or a tidal shore, so the names on the blocks mean something to them.
Standards this lesson supports
The Next Generation Science Standards give you three useful anchors for grades 6-8:
- MS-LS2-4: construct an argument supported by empirical evidence that changes to physical or biological components of an ecosystem affect populations. The tower and the recording sheet supply the evidence.
- MS-LS2-5: evaluate competing design solutions for maintaining biodiversity and ecosystem services. Use this in the extension, when students propose how to protect the tower.
- Core ideas: LS2A (interdependent relationships in ecosystems), LS2C (ecosystem dynamics, functioning and resilience) and LS4D (biodiversity and humans) describe the ideas the game dramatises.
MS-LS4-1 covers the existence, diversity, extinction and change of life forms through the history of life on Earth. Treat it as a separate follow-up on species extinction, because the tower does not model the fossil record.
The simplest version: label, stack and pull
Start here with every class. This version needs no special rules and shows the basic link between species loss and instability.
- Pick the ecosystem. Write a list of plants, animals, fungi and decomposers that belong to it. Aim for a mix of producers, consumers and decomposers so a food web can be drawn afterwards.
- Label the blocks. Lay the blocks out in rows and write one species name on the end of each, so the name stays visible after stacking. Give related species neighbouring blocks if you want students to spot links later.
- Build the tower. Stack it the standard way, mixing the labelled blocks so no group of related species sits together by accident.
- Take turns. A student removes any block they can without toppling the tower and reads the species name aloud. That species is now lost from the ecosystem.
- Record each loss. One student logs the species removed, the order, and what the tower looks like after each turn.
- Stop at collapse. The round ends when the tower falls. Keep the fallen blocks on the table for the debrief.
Checkpoint before escalating
Move on only when students can say, in their own words, which removals changed the tower and which seemed to do nothing. If they treat it purely as a dexterity game, pause and ask them to name the species before each pull. Early removals often leave the tower looking fine, which is a useful starting point for a talk about how losses can go unnoticed.
Escalation: keystone species and linked losses
In the plain version every block has equal weight, so the tower shows the number of losses rather than their kind. A keystone rule fixes that. Wooden blocks are physically identical, so no block is a keystone species by nature. The designation is a rule you add, and you decide which blocks carry it.
Which blocks should represent keystone species?
Choose a small number of species whose role in your chosen ecosystem you can explain in a sentence, and mark their blocks with a star or a coloured dot. Seed them toward the lower and middle layers of the tower, where pulling a block is riskier and the effect is more visible. Keep a card for each keystone species that states what it does for the habitat, so students can check the logic when you debrief.
Linked-loss rule
When a keystone block is removed, the group must also remove the blocks for the species named on its card as dependent on it. This turns a single loss into a chain and shows the idea in LS2A, that species in an ecosystem depend on one another. Add this rule only after a plain round, so students can compare the two towers.
A keystone lesson for a food web
If students have already drawn a food web, have them place arrows between the labelled species before play. After the keystone round, they redraw the web with the lost species crossed out. The comparison between the two diagrams is the evidence for MS-LS2-4, and it feeds the class’s own view of ecosystem resilience.
Escalation: adapt it to a local species
The NSTA description notes the activity can focus on a locally endangered plant or animal, which can be determined by contacting local governmental agencies. That makes it a strong second lesson. Ask the agency or a local conservation group which species are of concern near your school, then build the block list around that species and the organisms it depends on.
This version works well with older students or a class that has completed the plain round. Students can then take on the MS-LS2-5 task: propose and compare ways to protect the species, and decide which proposal best maintains biodiversity. For ways to build that kind of questioning into fieldwork, see our guide to inquiry based science teaching outdoors.
When to stop or change the game
- Stop when the tower falls. A collapse is the natural end of a round and the best prompt for discussion, so do not rebuild and restart before the debrief.
- Stop early if play turns into a contest. If students are racing or competing to topple the tower, pause and return to naming species and recording losses.
- Simplify if the tower is unstable from the start. A poorly stacked tower falls for reasons unrelated to ecology, which undermines the model. Rebuild it before play.
- Do not add rules mid-round. Introduce the keystone and linked-loss rules at the start of a new round so each tower tests one change.
Fallen blocks are the moment most classes want to react to. Leave them where they landed.
Debrief script
The debrief is where the activity becomes science. Ask these questions in order, and ask students to answer using their recording sheets as evidence rather than memory.
- Describe the pattern. Which removals did the tower tolerate, and which made it noticeably less stable?
- Connect to the web. Which lost species were linked to others on your food web, and what happened to those links?
- Test the keystone idea. Did removing a starred block change the tower more than an ordinary block? What would you expect in the real habitat?
- Argue from evidence. Make a claim about how species loss affects a population, and support it with a specific moment from your log. This matches MS-LS2-4.
- Propose a fix. What could a community do to keep this ecosystem’s biodiversity intact? Compare at least two ideas and say which you prefer and why.
Students who like to reflect in writing can continue in a field notebook; our guide on how to teach nature journaling shows how to structure those entries.
Where the Jenga model misleads
Tell students plainly that the tower is a model, and models simplify. A strong debrief includes a short critique, because MS-LS2-4 asks for arguments built on evidence, and that includes the limits of your own evidence. Raise these points:
- Physics, not ecology, decides. The tower falls because of balance and the player’s hand. Which species a food web can lose depends on how the species relate to each other, as LS2A describes. A block that is easy to pull says nothing about how important a species is.
- One outcome only. The tower either stands or falls. Ecosystems can change gradually, and LS2C is about dynamics and resilience, not a single switch. Ask students what a partial collapse might look like in a real pond or forest.
- Species are not interchangeable bricks. Every block is the same shape, but real species differ in numbers, roles and how many others rely on them. The keystone rule is something you add by hand to make up for that.
- Nothing can recover. Removed blocks stay removed, and no species moves in or adapts. Ask students what a real ecosystem might do that the tower cannot.
- Humans are missing. The game has no pressure from people, though LS4D connects biodiversity and human activity. The fix-it question in the debrief brings people back in.
Finishing on these limits keeps the activity honest. Students learn the content and also learn how scientists judge a model.
Frequently asked questions
How do I set up a Jenga game to model species loss?
Label each block with a species from one ecosystem, stack the tower, and have students remove blocks in turn, logging each lost species. Add keystone and linked-loss rules only in a later round.
Can I use the activity with a local endangered species?
Yes. NSTA’s description says the focus can be a locally endangered plant or animal, which you can identify by contacting local governmental agencies. Build the block list around that species and its relationships.
Which standards does the lesson match?
MS-LS2-4 fits the evidence-based argument, MS-LS2-5 fits the protection proposals, and LS2A, LS2C and LS4D supply the core ideas. All are middle school, grades 6-8.
What if the tower falls on the first few turns?
Rebuild it and check the stacking. A tower that fails early is usually unstable rather than informative, so it does not model species loss well.