Sorting Plants by the Creation of a Dichotomous Key

Part of the "Which Plant is Which?" Collection

Back to Collection

Goal

Students will classify organisms into groups and relate the determined groups with how and why scientists use classification.

Estimated Time

45 Minutes

Setting Required

Outside

Standards

  • S5L1. Students will classify organisms into groups and relate the determined groups with how and why scientists use classification.
    • b. Demonstrate how plants are sorted into groups

Materials

  • Journals or 8.5×11 copy paper (1 per student)
  • Coloring supplies (enough for each student)

Procedures

  1. Explain to students that in their small groups they will be tasked with sorting all of the plants in a certain area of the schoolyard based on the observable characteristics that they have in common.
  2. Model for students how to create a dichotomous key for the selected plants by developing opposing statements or yes/no questions in which each plant in the group fits into one of the two categories (then continues to subdivide until each plant is in it’s own group).
  3. Provide plenty of time for small groups to work together to develop their original classification system before sharing back to the group.
  4. Explain to students that over the years, scientists have used various criteria to group plants from growth form to medicinal effects (or other uses) to arrangement of flower parts. Modern classification is based on common ancestors and shared evolutionary history revealed in a plant’s DNA.