TREE SCIENCE BOX ACTIVITY: . MAKING A DICHOTOMOUS LEAF KEY
Amy Edwards

PURPOSE:

To help students identify different trees and develop an understanding of the scientific process of classification and using a dichotomous key.

MATERIALS:

Two or three examples of the leaves from each type of tree in your school yard Copies of 'Native Trees of Georgia' (and/or other tree guides).

INTRODUCTION:

Classification is a way scientists divide large groups of organisms into smaller closely related groups. Classifications are largely bascd on internal anatomy and development. To classify an organism you must know a lot about it. Scientists of~ten use dichotomous keys written by experts to help them identify plants and animals. This type ol~ key offers the user a series of choices between two alternative descriptions (hence the name dichotomous). This activity is designed to introduce students to the scientific process of classification and using a dichotomous kcy. Give each student or group of students copies of 'Native Trees of Georgia', a list of suggested leaf characteristics, one set of leaves and an activity sheet. Ask them to use the workshect to develop a key to the leaves. After they are done, have them try to use each others keys to identify the leaves. Have the students discuss what leaf characteristics work best to differentiate species.

ADDITIONAL ACTIVITIES:

1. Ask students to list different characteristics or traits that were used in the key.

2. Ask the students to explain how trees from different taxa (families, genera, classes) are different or similar to each other.

3. Ask the students to make an identity card for some of the trees.

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