Dichotomous Key Challenge

Dichotomous Key Challenge

Read each question carefully and follow the instructions to complete the dichotomous key activities.

A dichotomous key is a tool used by scientists to identify unknown organisms. It presents a series of choices, each with two options, that lead you to the correct identification. 'Dichotomous' means 'divided into two parts'.

1. What is the main purpose of a dichotomous key?

2. The word 'dichotomous' means divided into   parts.

Use the dichotomous key below to identify the different leaves shown. Write the name of the leaf next to its corresponding letter.

Dichotomous Key for Leaves:

1a. Leaf is simple (one blade per petiole)...................................................Go to 2 1b. Leaf is compound (multiple leaflets per petiole)......................................Leaf F 2a. Leaf has smooth edges...................................................................Go to 3 2b. Leaf has jagged or lobed edges.........................................................Go to 4 3a. Leaf is oval-shaped.......................................................................Leaf A 3b. Leaf is heart-shaped.......................................................................Leaf B 4a. Leaf has deep lobes (like fingers).......................................................Leaf C 4b. Leaf has small jagged teeth.............................................................Go to 5 5a. Leaf is long and narrow...................................................................Leaf D 5b. Leaf is wide and roundish................................................................Leaf E

3. Leaf A:  

4. Leaf B:  

5. Leaf C:  

6. Leaf D:  

7. Leaf E:  

8. Leaf F:  

9. A dichotomous key always gives you two choices at each step.

10. You can skip steps in a dichotomous key if you think you know the answer.