Look at these four Irish animals: a robin, a frog, a bat and a hedgehog. Split them into two groups using one thing you can see. Then try a different split. Which split would help someone else find each one again?

A branching key is a path of yes-or-no questions that ends on a name. Every question splits what is left into two.

Here is one for four vehicles: a bicycle, a bus, a boat and an aeroplane.

Question 1: does it have wheels that touch the ground?
No: the boat and the aeroplane... but an aeroplane has wheels too. A key needs an answer you can be sure of.

Better question 1: does it travel on water?
Yes: the boat.
No: the bicycle, the bus, the aeroplane.

Question 2: does it have an engine?
No: the bicycle.
Yes: the bus and the aeroplane.

Question 3: does it fly? And now every one has its own end.

Your wildlife cards are next, and the questions are yours to choose.

In your group, build a branching key for the eight Irish animal cards. Follow these steps:

1. Spread out all eight cards.
2. Find one feature you can see that some cards have and some do not. The best one splits the cards into two groups of about the same size.
3. Write it as a yes-or-no question on a sticky note. Check that every card gets a sure Yes or a sure No.
4. Put the Yes cards on one side of the note and the No cards on the other.
5. Take one group and do the same again. Keep going until every card is on its own.
6. Write the animal's name at the end of each branch.
7. Test it: pick a card, start at the top and follow the questions. Do you land on the right name?

Then record your finished key on your Investigation Journal page: each question in order, and which animal sits at each end point.

On the board you will see the same eight Irish wildlife cards you sorted on paper. We will answer one clear yes-or-no feature question at a time and send each living thing to its own end point, until every card sits on its own. Watch where each card goes and say if you agree or if you would have answered differently.

A mystery Irish wildlife photo is on the board. It is not one of the eight cards you sorted. We will follow our shared class key below. Answer each question from what you can see, not by guessing a name, and record each decision and the name you reach on your Investigation Journal page.

1. Does it have feathers?
2. Does it have six legs?
3. Does it have wings made of skin?
4. Does it have fins and scales?
5. Does it have spines or prickles?
6. Does it have a hard spiral shell?
7. Does it have smooth damp skin?
8. Does it have fur?
9. Does it have a black-and-white striped face?