1. Vertebrate (has a backbone)
 *GO TO 2*

Invertebrate (does not have a backbone)
*GO TO 7*

2. Body covered with hair or fur
MAMMAL

Body not covered with hair or fur
*GO TO 3*

3. Body covered with feathers
BIRD

Body not covered with feathers
*GO TO 4*

4. Body covered with leathery, hairless skin
REPTILE

Body not covered with leathery, hairless skin
*GO TO 5*

5. Has gills
FISH

Does not have gills
*GO TO 6*

7. Has an exoskeleton - arthropod
*GO TO 8*

Does not have an exoskeleton
*GO TO 12*

8. Has six legs and three parts to the body
INSECT

Does not have six legs
*GO TO 9*

9. Has eight legs and two parts to the body
SPIDER

Does not have eight legs
*GO TO 10*

10. Many pairs of legs, some 'feathery' and used as gills
CRUSTACEAN

Many pairs of legs. No gills. Long, segmented body
*GO TO 11*

11. One pair of legs on each segment.
CENTIPEDE

Two pairs of legs on each segment
MILLIPEDE

12. Star-shaped with five 'arms'
STARFISH

Does not have five 'arms'
*GO TO 13*

13. Long, soft body; sometimes segmented; no legs or antennae
WORM

Soft body, sometimes protected by a shell. May have eight 'arms'; may have antennae
MOLLUSC