To show students that many kinds of living things can be sorted into groups in many ways using various features to decide which things belong to which group and that classification schemes will vary with purpose.
This lesson is the first of a two-part series on classification. At this grade level, students should have the opportunity to learn about an increasing variety of living organisms, both the familiar and the exotic, and should become more precise in identifying similarities and differences among them. Firsthand observation of the living environment is essential for students to gain an understanding of the differences among organisms.
Classification 1: Classification Scheme is intended to supplement students' direct investigations by using the Internet to expose students to a variety of living organisms, as well as encourage them to start developing classification schemes of their own.
Classification 2: A Touch of Class extends this thinking by exposure to the idea that a variety of plants and animals (organisms) can be classified into one or more groups based on the various characteristics of a specific group.
This lesson gives students the opportunity to look at and discuss different classification schemes. Learning about a variety of living organisms helps them identify the similarities and differences among them. Further, this information will help students realize that there are many ways to classify organisms but that any classification scheme depends on its usefulness. It follows that a classification is useful if it contributes either to making decisions on some matter or to a deeper understanding of the relatedness of organisms.
Research suggests that upper elementary-school students tend to group certain organisms in mutually exclusive groups rather than a hierarchy of groups. Because of this tendency, students may have difficulty understanding that an organism, for example, can be classified as both a bird and an animal. Further, students do not recognize that trees, vegetables, and grass are all plants. Students also tend to group things either based on observable features or based on concepts. For example, when students distinguish between plants and animals, they often use such criteria as number of legs, body covering, and habitat to decide whether things are animals. Finally, elementary-school students typically use criteria such as movement, breath, reproduction, and death to decide whether things are alive. For example, some students believe fire, clouds, and the sun are living organisms, while others think plants and certain animals are nonliving. (Benchmarks for Science Literacy, p. 341.)
Students will access animal cards that are part of the Animal Movements lesson on the Utah Education Network site. Students could access these cards online, or you could print them out and make copies for students ahead of time.
Start this activity by having students participate in a brainstorming session where they come up with different ways in which objects or living organisms could be grouped (e.g., size, shape, or color). Ask students to write down their ideas in their journals.
Then, ask students to think about some common objects they might find around their homes, like clothes.
Ask questions such as:
- Could your clothes be divided into different groups (like pants, shirts, shoes)? If so, how would you divide them?
- What about the dishes in your kitchens? How would you group those?
Next, divide students into three groups and assign one of the items listed below to each group. Have each group practice classifying objects according to physical structure and features. You should have the following items on hand:
- A box of assorted buttons
- A box of assorted tools
- A box of assorted keys
Ask students to group the items according to any feature they choose. Each group of students should keep a written record of how they divide the objects. Then have students share their classifications with the rest of the class.
- What features did you use to divide the items?
- Do you believe that the way you have divided the items is useful in helping you to better understand the properties of the items?
- What other features could you use to further divide your items?
As you continue with this lesson, you should be aware that elementary-school students hold a much more restricted meaning than biologists for the word “animal.” Most students list only vertebrates as animals. Also, because upper elementary-school students tend not to use hierarchical classification, they may have difficulty understanding that an organism can be classified as both a bird and an animal.
Explain to students that scientists classify animals depending on the features they share and that animals can be classified in a number of different ways. For instance, they can be classified by where they live, by what they eat, and by their body structure.
Refer your students to the animal cards that are part of the Utah Education Network site. You can either have your students work online for this exercise or you can print out the page ahead of time and make copies for your students to use. Ask each group of students to divide the animals based on whatever feature they choose. Remind them to write down in their journals how they have grouped the animals.
Ask students the following questions:
- Are there features that are shared by all of the animals? If so, what are they?
- What features vary from animal to animal?
- What features did you use to divide the animals?
- Are there other features you could use to place the animals into different groups?
As you are probably aware, when you ask younger students to group animals, they may have a tendency to place each animal into its very own group. If this happens with your students, continue the exercise by asking them to search for common features between at least two animals, then at least between three animals.
You can help students along by asking them to think about grouping the animals according to the following criteria:
- Animals that run
- Animals that hop
- Animals that swim
- Animals that crawl
- Animals that fly
You can add pictures of other animals to this set of cards, as well as ask students to group them as many times as you see useful.
Once students have finished grouping the animals, ask them the following questions:
- How did you group these animals?
- Did thinking about how these animals move (e.g., run, hop, swim, crawl, or fly) help you to group them? If so, how?
- Did the information you learned about each of the animals help you to make your classification scheme more useful?
Follow this lesson with the second lesson in the series on classification: Classification 2: A Touch of Class.
For an additional Living Environment lesson for grades 3-5, go to Pond 1: Pond Life.
The online unit of study called Living Things on the Franklin Institute website has a section called Families that can further your students' understanding about classification.
The classification of animals into groups helps broaden students' understanding about the diversity of life. To help emphasize the differences and similarities between species, you can refer your students to the Classifying Critters page of The Cool Science for Curious Kids website. In this activity, students are given a chance to test their knowledge about different species.