Creating a Dichotomous Key for Amphibians
suggested grade levels: 9-12/College
view Idaho achievement standards for this lesson
1. The students will learn how to use the Digital Atlas of Idaho.
2. The students will learn how to make a dichotomous key.
3. The students will improve their observational skills and learn how to recognize defining characteristics.
1. To get there: Click on Atlas Home, Biology, Amphibians, Identification Pages, then on Adult Comparator Page.
2. Using the Comparator Page, students will construct a dichotomous key to distinguish these species from each other. Click on the species listed below to see a picture of it. On the other side of the screen, click on another species for a picture of it and then compare the pictures. After comparing these pictures, decide on a characteristic that you could use to distinguish between these species. Each group should decide on its own defining characteristics. Use these defining characteristics to make a key that will distinguish the following species from each other. Teachers can write the names of these species on a blackboard.
1. Long-tailed Salamander
2. Idaho Giant Salamander
3. Rough-skinned Salamander
4. Western Toad
5. Woodhouse's Toad
6. Pacific Treefrog
8. Wood Frog
3. If time permits, have groups exchange papers and see if other groups can distinguish these species using a different group's set of defining characteristics.
These are links to access the handouts and printable materials.
Adult Comparator Page