1. A ‘key’ is the name given to a means of identifying plants and animals. It usually consists of a set of written descriptions which have a starting point which is very general and then the descriptions become more and more specific until the description can only fit one animal or plant. It is very difficult to find an example of a simple branched key. Most keys produced commercially cover a wide range of organisms and are very complicated.

In order to use a key, you must have a very good description of the animal or plant and have looked at it closely.

Worksheets C21a (G) and C21b (G) show a selection of invertebrates - animals which don’t have a backbone. C21c (G) is a simple key which can be used to identify these animals. Choose an animal to start e.g. number 2. Look at the picture then start at number one on the key. No, it does not have wings so go to 2. Yes it does have a shell so go to 10. Yes it does have a large shell which sits on top of its body so it is a snail.

You must follow the questions strictly in order. Give the children copies of the key in pairs or groups and perhaps three or four animals from the worksheets for them to identify.

The names of the invertebrates are given below.