1. Unit 12 Our Last Unit!! Dichotomous Key

2. Dichotomous = branched into TWO divisions

3. Dichotomous Key = a key that helps scientists organize and identify organisms

4. How to use a Dichotomous Key: 1. Read first set of questions. 2. Decide which one best describes your organism. 3. Follow directions for that question.

5. Example:

6. 1a. With a holeGo to Question 2 1b. Without a holeGo to Question 3 2a. Six sidedIt is Species #1 2b. Four sidedIt is Species #6 3a. With threadingGo to Question 4 3b. Without threadingIt is Species #8 4a. Pointy tipGo to Question 5 4b. No pointy tipGo to Question 6 5a. Rounded headIt is Species #4 5b. Not rounded headIt is Species #7 6a. Flat headGo to Question 7 6b. Not flat headIt is Species #2 7a. Body length twice the width of headIt is Species #5 7b. Body length not twice the width of head It is Species #3

8. Common Plant Terms: Compound Leaf = a leaf separated into leaflets Simple Leaf = a leaf that is NOT separated into leaflets

9. Common Plant Terms: Palmate leaflets= leaflets arranged like the fingers on your hand Pinnate leaflets= leaflets arranged like a feather.

10. Common Plant Terms: Jagged Leaf Margin = rough edge of leaf Smooth Leaf Margin = smooth edge of leaf