What is a key?

A key contains a series of questions which are designed to identify an animal or plant that you cannot name. The questions are normally in pairs and you choose the right answer that leads you onto the next pair of questions. At the end of the question session, you end up with the name of the animal or plant you are trying to identify.

Keys that use this 'two question' system are called Dichotomous keys.

How do you use a key?

The key is rather like a detective trying to identify a criminal where he asks the witness a series of questions which gradually narrow down the suspect to one person.

An example is shown below:

The criminal is one of the seven people shown in the picture. A policeman needs to identify a person that a witness has observed at the scene of the crime but the interview has to be carried out over the phone. The policeman will read out the following key to identify the suspect.

The actual criminal is Mr. Uglow!! and your witness saw the real criminal

         Question                               Answer 

1. a)Did he/she wear a dress?                go to question 2
   b)Did he/she wear trousers?               go to question 3

2. a)Did he/she wear glasses?                This is Miss Sully
   b)Did he/she not wear glasses?            This is Miss Tickle

3. a)Was he/she bald?                        This is Mr. Ladd
   b)Did he/she have hair?                   go to question 4

4. a)Was his/her hair dark?                  go to question 5
   b)Was his/her hair blonde                 This is Mr. Earnest

5. a)Did he/she wear glasses?                This is Mr.Rims
   b)Did he/she not wear glasses?            go to question 6

6. a)Was his/her hair parted to one side?    This is Mr. Twit
   b)Was his/her hair parted in the middle?  This is Mr. Uglow

Try the key out: you play role of the policeman and interview a friend who is the witness

Go to the Full Scientific key or the Graphic key.