To show students that many kinds of living things (e.g. plants and animals) 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 second 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. First-hand 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.)
As a way to stimulate student thinking about classification and to review what they learned in the first lesson of this series, conduct a class brainstorming session asking questions like these:
- What is an organism?
- Can you think of any living things?
- What are some similarities (and differences) of plants and animals?
- Do you think that within plants and animals there are similarities and differences?
- What are the basic needs of animals and plants?
- (An individual living thing that carries on the activities of life by means of organs which have separate functions but are dependent on each other.)
- (Answers may vary.)
- (Some similarities are that they are both organisms that are multicellular [made of more than one cell] and they both have a life cycle. Some differences are that most plants use photosynthesis [use of sunlight] as their mode of nutrition whereas animals use ingestion as their mode of nutrition; plants and animals have different ways of reproduction; and animals have sensory and nervous systems whereas plants do not.)
- (Answers may vary. Encourage students to support their ideas with explanation.)
- (For animals, the basic needs are air, water, and food. For plants, the basic needs are air, water, and light.)
You may want to write down students' responses on a piece of newsprint so that the class can revisit these questions and their responses at the end of the lesson.
Next, review with students why it is useful to sort/classify things. You might ask:
- In Classification 1: Classification Scheme, you learned how to group things (e.g. animals) based on certain features. What features did you use?
- Was it useful to group things based on these features? Why or why not?
- In what other ways is classification useful?
- (Run, hop, swim, crawl, and fly.)
- (Answers may vary.)
- (Classification is useful because it enables one to make decisions about things [e.g., if one knows that a mammal is part of a group termed primates, then one knows that the animal is intelligent, can grasp things with its hands, etc.]. It is also useful because it allows us to identify similarities and differences among living things.)
In this activity, students will classify plants and animals into groups based on certain characteristics (e.g., plants, animals, things that lay eggs, things that live underwater). By doing this, they will visualize and learn how the same plant or animal can be classified into more than one group depending on the features of a specific group.
Have students use the A Touch of Class student esheet to access the A Touch of Class online interactive activity. The esheet includes both instructions on how to play the online activity* and questions regarding the activity. Answers to the questions can be found in the Learn More section or by playing the game.
*Note: You can decide how to have students keep score. The computer will calculate the score but, if this is important, then you can ask students to record scores on paper.
The following questions are found on the student esheet. Students can either respond to the questions online, using the online question and answer tool, or using the printable Grouping Organisms student sheet. You may want to encourage your students to take notes on what they learn by playing the game or from the Learn More section.
- What do some plants need to make their own food? (Sunlight.)
- What living things eat insects? (Some animals and some plants.)
- Name some animals that fall under the mammal category. (Humans, whales, and the duck-billed platypus.)
- What are some characteristics of mammals? (They are a group of animals that usually have hair, fur, and nurse their babies with their own milk.)
- What birds cannot fly? (Ostriches and penguins.)
- In what ways can animals protect themselves? (Some examples are by using poison or venom, by blending into their environment, and by playing dead.)
- Can you think of any animals that do not have backbones? (Insects and jellyfish.)
- What living thing is an arachnid but is often mistakenly classified as an insect? (Spider.)
- Name an example where the same plant or animal can be classified in more than one group depending on the features of a specific group. (One example is a robin [a bird] can be grouped under "things that fly" or "things that have a tail.")
Review with students that they should now understand that many kinds of living things (e.g. plants and animals) 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.
As a group, revisit the questions and answers from the beginning of the Motivation section. Have students' responses changed after going through this lesson?
To further assess their understanding, have students create a new "screen" for the online activity they did in the Development section. That is, they should create a category (e.g., Animals that Hibernate) and 16 possible plants and animals (some that are the correct answers and some that are not) from which to choose.
Then have them share their screen with a classmate and have the other student choose the correct animals and/or plants.
How did they do? Review their screens, as well as how they scored their partner's work.
The Science Update called All Species Inventory takes a look at taxonomy, the science of classifying and naming living things according to how similar they are to other creatures, and how a group of scientists and Silicon Valley entrepreneurs is trying to bring the musty field of taxonomy into the twenty-first century.
National Geographic Kids would be a good place to go for students to learn more about various animals, from bats to warthogs.