Timed classification challenge
The student is handed a tray of specimens — leaves, shells, insects, seeds, pictures of animals — and a clock. Working against time, they look closely at each one, pick out the traits that matter, and follow a dichotomous key step by step to sort and name them. At the end they say what each specimen is and back it up with the traits they saw. There is nothing to copy: the specimens are real, the time is real, and the identification has to hold up.
| Criterion | Not yet | Approaching | Mastered |
|---|---|---|---|
| Systematic sorting | Sorts at random and loses track of which specimen is which. | Has a rough plan but jumps around the key or forgets which specimens are already done. | Works through the specimens in order, follows the key one step at a time, and keeps every specimen tracked without confusion. |
| Observing traits carefully | Guesses from a quick glance and misses the traits that matter. | Notices big traits like size or color but overlooks smaller ones like leg count or leaf edges. | Looks closely with a hand lens, notices the traits the key asks about — number of legs, body symmetry, leaf shape, presence of a backbone — and describes them clearly. |
| Using a dichotomous key | Cannot follow the two-choice steps, or picks whichever branch looks easier. | Follows the key for a few steps but takes a wrong branch and doesn’t notice. | Reads each either/or step, chooses the branch the evidence supports, and follows the key all the way to a name. |
| Working carefully under time pressure | Rushes, mixes up specimens, or skips steps as the clock runs down. | Generally careful but gets sloppy near the end — skims a step or double-handles specimens. | Stays deliberate under pressure: handles each specimen once, checks the key, and keeps the tray organized throughout. |
| Identification & justification | Names a specimen with no trait to back it up. | Names the specimen but cites only one trait, or hedges between two groups. | Names each specimen and justifies it by chaining the traits and the key steps into a single, clear conclusion. |
“This one has six legs, three body parts, and a pair of antennae, so the key sends it to ‘insect’ — not the spider, which would have eight legs. I checked the leg count twice before I wrote it down.”
“It’s a bug of some kind. It has legs, so maybe an insect? I’d have to guess which group without looking it up.”
This assessment is AI-proof by design: it happens at the bench, with real specimens, against a real clock. No chatbot can turn a leaf over, count an insect’s legs, or pick the next branch of the key while the timer runs. The trays differ from student to student, so there is no answer to look up — mastery is shown by sorting and justifying in person, not by submitting.