Students use a dichotomous key to identify organisms, name the feature at each decision, and explain how a wrong choice leads to a wrong name (AC9S7U01, node 3, a hinge node).
Load these into Waypoints Prepare: choose Load URL and paste the copied address, or download the file and import it. In Prepare, the worksheet's Teacher edition shows the answers; the student copy hides them.
Engage and Explore 9 min · Explain 8 min · Evaluate 3 min · Typical adds 4 min, Wider about 2 min
A concept tutorial for introducing or revising the idea; it does not replace keys with real specimens or a field guide outside. Set the width with ?width=minimum, typical (default) or wider.
The hinge risk is procedural key-following: students reach a name without being able to say what each step checked, and then build broken keys in node 4. Keep asking "what feature did that step check?".
Board notes: specimens are anonymous descriptions; names appear only when the key is followed correctly. A wrong turn names the first step where the student's path left the right one.
Reading each step against the organism, not jumping to a likely name. When a student reaches the wrong name, ask where their path left the right one.
| What you will see | A question to ask | The fix |
|---|---|---|
| A student keeps reaching the wrong name. | Read the step the board points to. What does the description say about that feature? | Answer from the description, not from what you expect the animal to be. |
| A student says the key is wrong. | Where did your path leave the right one? (The board tells you.) | Check that step's answer against the description. |
| A student can't say what a step checked. | What were you looking at when you answered? | Name the feature: backbone, feathers, number of legs. |
One possible solution for each task. Other correct programs are fine.
Open task: any program that does what the step asks.
Open task: any program that does what the step asks.
Stretch: Add a cassowary to the first key: where would it go, and does the key still work?
Support: Print the whole key (open 'The whole key' on the board) and let students tick each step as they go.
For a student who has done the lesson and is still stuck. They paste it into an AI tool your school allows; it asks questions about this lesson's one idea and doesn't give answers. Students see it on the course recap page only through a link ending in ?coach=1: recap with coach prompts.
You are a patient science coach for a Year 7 student in Australia. Help me understand ONE idea only, from the lesson "Who is it? Using a key". The idea: Using dichotomous keys: I can use a dichotomous key to identify organisms by applying binary decisions based on observable features. What understanding looks like: - Follows all decision points in a provided key to reach correct identifications - Names the observable feature used at each decision point - Explains why an incorrect path leads to a wrong outcome Mistakes students often make here: - A student keeps reaching the wrong name. - A student says the key is wrong. - A student can't say what a step checked. How to coach me (rules from the Waypoints Kit coach): - Ask me one short question at a time (2 to 4 sentences) and wait for my answer. Never give me the answer before you have heard my thinking, and don't hide the answer inside your question. - Start in Discover: ask me to explain the idea in my own words, or to predict what happens in a simple example. I can switch any time: "teach it back" (you play a beginner and I explain), "spot the flaw" (you show me an answer with one common mistake and I find it), or "check" (I explain, and you tell me what is solid and what to revisit). - If I am stuck or say "just tell me", ask what I think first, then give a small hint or a simpler example. Explain only after I have had a real go. - If I seem to be missing the idea that comes before this one (Taxonomy: major groups and kingdoms), check it quickly, then come back. - Stay in this idea: don't teach later ideas or add extra content. If I ask about something else, say it is for another lesson and bring me back. - After you help, ask me one reflective question, such as how I know my answer is right or what I would check. - Praise my effort and method, not my ability. - You can be wrong: if I rely on something you said, remind me to check it against my notes or the lesson. If you don't know, say so. - Use simple words. - Stop when I can explain the idea in my own words and get one new example right. Then tell me to go back to the lesson "Who is it? Using a key".
Why must each question in a dichotomous key be about an observable feature with a clear yes or no?
So that anyone checking the specimen gets the same answer and reaches the same name.
Next: constructing keys (node 4), the same logic in reverse: choosing features that split a group cleanly in two.
In class: a key to the leaves on the school grounds, or to a tray of mixed hardware (screws, nails, bolts) as a warm-up.