Classification Keys

Despite the fact that 99.9% of all living organisms, that ever existed, are now extinct there is still a large variety on Earth today. Hence it is important to be able to classify organisms in order to be able to find out their names. Also classification helps scientists to be able to understand the relationships between organisms and to investigate the theory of evolution. Now we will try a simple sorting activity to organize some dogs into groups according to their similarities... Keys

Divide the dogs into two groups Group AGroup B We divide the dogs into groups by asking a question to which there is a yes or no answer... Is the dog large (above 65cm)?

Large DogsSmall Dogs We can now divide each group down into further sub divisions...

white and grey coatsbrown and black coats What question could be used to divide the large dogs down into further groups? Does the dog have a brown and black coat? No Yes

Finally the groups can be divided down into individual dogs to which we can then give the names. What question has been used to separate these two dogs? Does the dog have curly hair? Airedale TerrierRotweiller yes no

By asking questions that divide the dogs we can produce a key. To save space biologists list the questions and give instructions at the end as to which question to go to next. 1. Is the dog over 65cm tall? If yes go to question 2 If no go to question 5 2. Does the dog have a brown and black coat? If yes go to question 3 If no go to question 4 3. Does the dog have a wooly coat? Yes… Airedale Terrier No…Rotweiller

1. Is the dog over 65cm tall? If yes go to question 2 If no go to question 5 2. Does the dog have a brown and black coat? If yes go to question 3 If no go to question 4 3. Does the dog have a wooly coat? Yes… Airedale Terrier No…Rotweiller Copy down the key and then complete it to classify the rest of the large dogs. Hint: you will write question 4 Question: What will question 5 be about? Answer> The small dogs. Activity

Example Answer Does the tail curl upwards? Question 4 Yes No Akita Old English sheepdog

Activity Now complete the key, starting with question 5, for the small dogs. You can make your own questions up.

Does the dog have a snub nose? YesNo Question 5 Go to question 6Go to question 7 Example Answer

Does the dog have long hair? Question 6 YesNo Pekinese Bulldog

Question 7 Does the dog have very long ears? Yes No Basset hound Dachsund

Extension/Homework: Collect worksheet 1 – 4 Complete for homework Using Keys