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?

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.

Turn your sort into a branching key on one A4 sheet for your group, laid out like this example (it uses the minibeasts from the board, not your cards):

Your key is ready when every one of your seven living things ends alone, at its own name. Another group will follow it without your cards, so ask only what they can see.

Then copy one full path of your key, from Question 1 to a name, into the box on your Investigation Journal page.