Look at these seven Irish living things: badger, heron, earthworm, bee, fern, oak and frog. They are all different. What features could we use to put them into clear groups?

Look at our seven cards again. When we classify, we sort living things into groups that share a clear feature, and we say why each one belongs.

Try a quick first split with me: plant or animal? Oak and fern go one way; badger, heron, earthworm, bee and frog go the other.

The feature we just used is our criteria: the thing we chose to sort by. Which other feature could split the animal group next?

Now watch a branching key at work. A branching key is a set of yes-or-no questions. Each question splits the living things into two groups, and the key keeps going until every one stands alone with its own name.

Here are five minibeasts: worm, ladybird, spider, snail and ant. We will send each one down the key below, one question at a time.

Why would "Is it colourful?" be a bad question for a key?

Watch the key as we go. It starts almost empty: each answer opens the next question, and a name appears only when a card reaches it.

Your group has seven Irish living things: badger, heron, earthworm, bee, fern, oak and frog. Choose the criteria you will sort by, from the four under Think about below, and use a feature you can check by looking.

Turn your criteria into Question 1: a yes-or-no question you can answer by looking. Sort all seven cards into a YES pile and a NO pile, and be ready to say why each living thing sits where it does. Every card must have a home.

Write the criteria you chose, and your Question 1 with its YES pile and NO pile, on your Investigation Journal page.