Classification and Dichotomous Keys (Grade 7)
Free printable Grade 7 science worksheet on classification and dichotomous keys. Students work through a printed key to identify small animals, with a full answer key.
Classification and Dichotomous Keys
Use the dichotomous key below. Start at step 1, choose (a) or (b), and follow it until you reach a name. Then answer the last questions about classification.
KEY TO SOME SMALL SCHOOLYARD ANIMALS
1 (a) No legs ... go to step 2
1 (b) Legs present ... go to step 3
2 (a) Body protected by a coiled shell ... Garden snail
2 (b) No shell, soft body made of many rings ... Earthworm
3 (a) Six legs (three pairs) ... go to step 4
3 (b) More than six legs ... go to step 6
4 (a) Wings present ... go to step 5
4 (b) No wings ... Garden ant
5 (a) One pair of wings ... House fly
5 (b) Two pairs of wings ... European honey bee
6 (a) Eight legs (four pairs) ... Redback spider
6 (b) More than eight legs ... go to step 7
7 (a) Seven pairs of legs, body covered in overlapping plates ... Slater
7 (b) Long body of many similar segments, each carrying legs ... go to step 8
8 (a) One pair of legs on each body segment, flattened body ... Centipede
8 (b) Two pairs of legs on each body segment, rounded body ... Portuguese millipede
- 1.An animal has no legs, a soft body made of many rings. Work through the key. What is it?
- 2.An animal has seven pairs of legs, a body covered in overlapping plates. Work through the key. What is it?
- 3.An animal has six legs, one pair of wings. Work through the key. What is it?
- 4.An animal has a long body of many segments with two pairs of legs on each segment. Work through the key. What is it?
- 5.An animal has no legs, a coiled shell. Work through the key. What is it?
- 6.An animal has six legs, no wings. Work through the key. What is it?
- 7.An animal has a long body of many segments with one pair of legs on each segment. Work through the key. What is it?
- 8.Classification groups living things from largest to smallest. Which group is larger, a genus or a species?
- 9.Why do scientists use scientific names instead of common names?
- 10.Why must every step of a dichotomous key offer exactly two choices?