Sorting minibeasts with a key

Science · Insects & Minibeasts · ages 7-9

Name ______________________ Date ____________

Which question best splits minibeasts into insects and spiders?
- Does it have legs?
- Does it have six legs?
- Is it small?
What is a key, in this kind of science activity?
- A set of yes/no questions asked in order
- A drawing of every kind of bug
- A tool for opening a bug's shell
A key can help you name a minibeast you have never seen before.
Circle one: True False
Why doesn't "Does it have legs?" alone tell you if a minibeast is an insect or a spider?
- Both insects and spiders have legs
- Insects have no legs
- Spiders have no legs
A bug has six legs and wings. Follow the key: legs, yes. How many, six. Wings, yes. What is it most likely?
- A spider
- A worm
- An insect
The key asks how many legs a minibeast has. A spider is not an insect because it has how many legs?
Answer: ______________
You find a minibeast you have never seen before. It has eight legs and no wings. What does the key suggest?
- It is a worm, since it has no wings
- It is an insect, since it has legs
- It is not an insect, since insects have six legs
Zara skipped the legs question and jumped straight to "Does it have wings?". She got mixed up about a beetle. What went wrong?
- Beetles never have legs
- She asked the questions out of order
- The key only works on spiders

Answer key

For grown-ups. Fold this page away before handing over the rest.

Does it have six legs? · Both insects and spiders have legs, so you need to count them. Six legs means insect; eight means it is not.
A set of yes/no questions asked in order · A key here means a list of questions, not something that opens a lock. Each yes or no answer leads you closer to naming the minibeast.
True · A key only asks about what you can see, like legs and wings, so it works even on a creature you don't know yet.
Both insects and spiders have legs · Insects and spiders both have legs, so that question alone can't tell them apart. Counting the legs can.
An insect · Six legs and wings match the insect branch of the key.
8 · Spiders have eight legs. Insects have six, so the leg count is what separates them.
It is not an insect, since insects have six legs · Eight legs means it is not an insect, even though it does have legs and you've never seen it before.
She asked the questions out of order · A key works step by step in the same order every time. Skipping ahead can send you down the wrong path.