Lesson 16-17 - Dichotomous Key

Introduction

Over the next few days, you’ll work on a couple of projects. The first one is about making a dichotomous key. A dichotomous key helps identify organisms by directing you to look at the known organisms. “Dichotomous” means divided into two parts, which means that the dichotomous keys always present two choices based on the key characteristics of the organism in each step. By correctly selecting the right choice at each stage, you will be able to identify the name of the organism at the end. The further you divide the key, the more you learn about the organism you are trying to identify.

Materials

      • science journal
      • poster paper
      • markers
      • nature magazines
      • research materials like your Chromebook
      • scissors
      • glue

Activity

      1. Think of five common plants and five common animals. Some examples include dandelions, mosses, frogs, and butterflies. Then write some of their characteristics in your science notebook. Arrange your ideas in a t-chart in your science journal.
      2. Now you will make a chart in your journal to show how plants and animals can be sorted by their characteristics. On one side of the chart, write the title “Plants.” On the other side of the chart, write the title “Animals.” Under the “Plants” title, write two subtitles: Seed Producers, and Non-Seed Producers. Under the “Animal” title, write two subtitles: Invertebrates and Vertebrates. In the next step, you will place pictures of organisms in the correct location on your chart.
      3. Gather magazines and other print materials that show different types of plants and animals. Cut out examples of seed-producing plants and non-seed producing plants and glue them in the appropriate spot on the chart. Cut out animal photos to show at least one invertebrate and several vertebrates. From the vertebrate group, find an example of one of each of the following: fish, amphibian, reptile, bird, and mammal. If you have difficulty placing any organism in the correct group, consult research materials to help you.
      4. Label each of the vertebrates with its correct category.

Analyze your results

      1. Did you have any difficulties sorting organisms? Which organisms were most difficult to place in their correct category? 
      2. What are some additional plants and animals you could add to your poster if you had more pictures? Where would you place them? 
      3. What are some questions you have about sorting plants and animals?

 

 

 

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