Plant Diversity Bar Graphs -- Out Teach
In this lesson, students will explore and record data about different plants that they observe. Students will then create a bar graph to reflect the data that that they collected. For example, a student might find 7 tomato plants, 5 cabbages, and 4 squash plants; their graph would reflect these numbers.
Background For Teachers
This lesson can be done with crops, flowers, herbs or even in a wild growing area as long as students are able to identify different types of plants. If you are unfamiliar with the identity of the plants in the outdoor space, you will need signs to mark them (a good feature for the outdoor classroom regardless). The lesson can also be simplified by collecting data on things like: plants that have white flowers; plants that have pointy leaves, plants that have big leaves, etc. The main points are for students to understand the benefits of diversity in nature and to apply bar graph skills to a real-world setting. Warning: If exploring in weedy areas, make sure that it is free of poison ivy: "Leaves of three, let it be."
• Specific plant names
How can we represent plant diversity in a bar graph?
Ask students how they would feel if they were told they could only have one type of food for the rest of their lives. What if it was broccoli or tomatoes? How would it impact their health?
Use the student answers to begin a discussion about the importance of diversity, especially in the natural world.
Inform that student that they will be exploring the outdoor classroom to data about the different kinds of plants that they can find
This exploration can be relevant for most schools with or without gardens.
Have students work in pairs or teams to identify several different types of plants in the outdoor classroom. They may need to use identification signs but they can also rely on prior knowledge if possible. For simplicity they can identify plants that have common features such as pink flowers.
Have the students record the number of each type of plant they find with tally marks on a table. For example, if they choose to count tomatoes, they would tally up how many tomato plants they can count.
Differentiation: Use strategic groups or pairs to support students and consider providing pre-determined plants with pre-drawn tables. For students who need an extra challenge, have them search for the plants that they believe are represented in the highest and lowest numbers in the space.
• How do you know these are the same type of plant?
• Why do you think there are so many of this plant?
• Can you think of another way we could represent this data?
Have students gather in a seating are by using a loud call signal.
Ask students to share some of the data that they collected while you compile the data on a table on the whiteboard.
If the students are familiar with graphing, ask them if they can think of another way to show the data that was collected and lead them to talking about graphing and bar graphs. If they are being introduced to bar graphs, go straight to explaining how the data can be displayed in a bar graph.
Explain the components of a bar graph including the title, the axis, necessary labels and the numeric increments that makes sense to use for this particular set of data.
Discuss how the increments used might change depending on the size of the numbers in the set of data. For example, if they counted 100s of a particular plant, you might want the Y axis to read 0, 100, 200, 300, etc.
Explain that the size of the bar represents the number of plants of each type and that the bar graph can give an obvious and helpful picture of how many of each plant were counted.
Ask the students how this type of data might help farmers or scientists. (answers will vary: showing how much of the different crops are being grown; seeing how many of each particular plant grows in a certain area; monitoring changes in plant diversity over time).
Ask students to work in pairs (or individually if they have extensive experience graphing) to create a bar graph using the data that they collected.
Optional: Students may use graph paper to more easily line up their graphs.
Ask students to swap graphs with another student or pair of students and calculate the difference between the highest and lowest numbers represented on the graph.
Extensions and Connections
This same lesson can be performed with other aspects of biodiversity such as counting the numbers of different insects found in the garden.
Provide the students with constructed bar graphs representing another imagined garden space and have them compare multiple graphs to increase graph fluency.
Students can collect weather data over time to represent in a bar graph. Have them collect temperature readings in their journals each time they visit the garden until they have sufficient data to make a graph.