- Grade Level:
- Upper Elementary: Third Grade through Fifth Grade
On this field trip, students will learn the basics of tree identification at Great Sand Dunes and how to use a dichotomous key.
Large sheets of paper and markers for teacher and each group; different kinds of similar things (i.e. beans, paper clips, buttons, etc.); Tree Classification Key (.pdf); flagging to mark teaching sites; Great Sand Dunes Plant Handbook (optional, pdf)
Part 1: Bean classification
Students will learn the concepts of classification and organization with a dichotomous key.
- Divide students into small groups (three to four students/group) and distribute paper clips, beans, or other small objects.
- Have students sort their pile into two classification groups based on some characteristic that is logical to them.
- Students will write down a name for each group based on the characteristic that was used to split them.
- Have students divide each primary classification group into further splits, until all the 'species' of small objects have been classified and charted on paper.
- Call on several groups to share with the class what characteristics they used to classify their objects. Different group may have used different criteria, such as size, shape, color, or composition.
- How could you use your chart/key?
- How do you classify in every day life? (library, silverware drawer, fishing box, etc.).
Part 2: Keying out trees
Students will use dichotomous keys to identify common trees.
- Introduce the idea that scientists have classified plants in the same way as the students classified their small objects. Scientists use already-developed keys to help discover the identity of plants. Using keys helps scientists from different regions or countries make sure they are talking about the same plant.
- Tell the class that they are now botanists. What characteristics/clues would they use to classify plants? Generate a list as the students name characteristics, such as needles or broadleaf leaves, deciduous or evergreen, leaves scaly or needle-like, cones or flowers, needles in clusters or singly, etc.
- If performing this at Great Sand Dunes use this Tree Classification Key at the picnic area or on the Montville or Mosca Pass Trail. At school, create a dichotomous key for the species in your area.
- Mark the teaching area with flagging or establish boundaries. Have each group find a tree and key it out. Rotate groups among different trees for practice using the key.
Questions for student discussion:
Why do people classify things in their world? What are some problems with classifying? Should we classify things?