Biology - M. Murphy
Lab: Vertebrates
Use the key below to identify the vertebrate classification of the organism
shown.  Remember, always start with step one for each new organism.

If you did not yet complete the "Dichotomous Key: Protists" activity, do that
before this to ensure you are familiar with how to follow a dichotomous key.
Dichotomous Key for Vertebrates:

1a. Animal is not a vertebrate ............................................................................... go to 2
1b. Animal is a vertebrate ..................................................................................... go to 3

2a. Animal has a protein-carbohydrate exoskeleton .............................................
Tunicata
2b. Animal does not have an exoskeleton ............................................................ Cephalochordata

3a. Animal reproduces using shelled amniote eggs ............................................. go to 4
3b. Animal does not use shelled amniote eggs in reproduction ........................... go to 5

4a. Animal is an ectotherm ...................................................................................
Reptilia
4b. Animal is an endotherm .................................................................................. Aves

5a. Animal reproduces by placental live birth ....................................................... go to 6
5b. Animal reproduces by spawning ..................................................................... go to 7

6a. Animal is an ectotherm ...................................................................................
Chondrichthyes
6b. Animal is an endotherm .................................................................................. Mammalia

7a. Animal has a cartilage skeleton ...................................................................... Agnathan
7b. Animal has a bony skeleton ............................................................................ go to 8

8a. Animal is a tetrapod ........................................................................................
Amphibia
8b. Animal is not a tetrapod .................................................................................. Osteichthyes