Biology Crosscutting Concepts Disciplinary Core Ideas Is Lesson Plan Life Science Mathematics NGSS Phenomena Science and Engineering Practices Three-Dimensional Learning Middle School High School Grades 6-8
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Sensemaking is actively trying to figure out how the world works (science) or how to design solutions to problems (engineering). Students do science and engineering through the science and engineering practices. Engaging in these practices necessitates that students be part of a learning community to be able to share ideas, evaluate competing ideas, give and receive critique, and reach consensus. Whether this community of learners is made up of classmates or family members, students and adults build and refine science and engineering knowledge together.
In today's task, Why does population size change?, students engage in science and engineering practices and use the lens of cause and effect (crosscutting concept) to figure out there is a maximum number of buffalo an area can support based on the living and nonliving components of the ecosystem. This task has been modified from its original design to be used by high school students, families, and teachers in distance and home learning. While students could complete this task independently, we encourage students to work virtually with peers or in the home with family members.
Before you begin the task, you may want to access the accompanying Why does population size change? Google slide presentation.
Guidance. Students experience the phenomenon of a buffalo population reaching an equilibrium size in a particular environment through the use of a simulation. The goal is to get students to identify patterns in data to develop a cause-and-effect relationship between population size and available resources. Students will develop predictions using patterns they noticed from the simulation to identify cause-and-effect relationships.
Presenting the Phenomenon. Ask students to examine the buffalo population graph (slide 2) and to record any possible reasons to explain the population increase on the Student Task Sheet or piece of paper. Students' possible reasons may include increased amounts of food, decreased numbers of predators, or less competition for resources.
Next, show students the two images of buffalo herds grazing in the Serengeti (slides 3 and 4). Ask them to record what they notice and wonder on a sheet of paper. Students will revisit these questions at the end of the lesson during the Building Consensus discussion.
Examples of student responses
Guidance. Students use a simulation to investigate the effects of different factors on buffalo population size to figure out a particular environment has a maximum number of individuals within a population it can support. It is important to have students define which factors they want to investigate in the simulation, such as changes in amount of food, competition, space, and climate. Students should focus on one factor at a time to determine its effect on the buffalo population size.
Initial Investigation. Show students the tutorial video (see also slide 5), then have students run the Serengeti Consumers simulation to identify patterns in the buffalo population over time using the following parameters (default settings) (slide 6):
When students are ready to run the simulation, they need to click the Setup/Reset button, then Go/Pause to start the simulation.
Tell students to record the final population and share with a partner or group. Ask them to record everyone's data in Table 1 on the Student Task Sheet. (If students are completing this task asynchronously, have them run the simulation a total of three times using these parameters). Once students have gathered all their data, ask them to analyze the data and identify any patterns they see.
Students should notice a pattern in the final population sizes from simulation to simulation. Use this pattern to introduce the science idea of carrying capacity by saying, "Scientists have a term for the maximum number of organisms of a species that an ecosystem can contain. They call this carrying capacity." (slide 7) Have students record the carrying capacity of this ecosystem based on their data. The carrying capacity should be around 40 buffalo using the above parameters.
Further Investigations. Instruct students to investigate at least two different changes in the ecosystem (slide 8). They may choose to look at changes in the following factors:
To make changes to the simulation, students need to first click the Set Up/Reset button.
Before students press the Go/Pause button, ask them to predict what will happen to the buffalo population based on the changes they made to the ecosystem. Remind students to record the parameters for each investigation and the final buffalo population size in Tables 2 and 3 on the Student Task Sheet.
Guidance. Students will make connections using patterns in data to develop a cause-and-effect relationship between the buffalo population and changes in the ecosystem.
Show slide 9 and give students time to share their data from the simulations they ran with one another, then ask them to respond to the following prompts, also found in the Student Task Sheet.
Take a moment to look back at what we have figured out from the simulation using the prompt on slide 10 to guide the discussion. Give students some time to respond to the prompt before asking them what they have written.
Prompt. What conclusions can be made about how changes in an environment can impact the carrying capacity of specific organisms?
Guidance. It is important to allow students to document what they have figured out on their own in their own words. During the discussion, the students should do most of the talking, and the adult is there to listen and prompt the student. Some suggested prompts are these:
This lesson begins to build understanding of the complex relationships that govern ecosystem dynamics. If you are interested in the storyline this task was excerpted from, see the Acknowledgements section below.
While the Serengeti isn't a place most students have personally experienced, they can connect the rules that govern this large ecosystem to the ecosystems around them. Families can expand on the ideas in this learning task in many ways at home, including these:
Another resource you could explore is the episode The Serengeti Rules from the PBS series Nature.
NSTA has created a Why does population size change? collection of resources to support teachers and families using this task. If you're an NSTA member, you can add this collection to your library by clicking ADD TO MY LIBRARY, located near the top of the page (at right in the blue box).
The NSTA Daily Do is an open educational resource (OER) and can be used by educators and families providing students distance and home science learning. Access the entire collection of NSTA Daily Dos.
This Daily Do is inspired by and uses materials from the How Do Small Changes Make Big Impacts on Ecosystems? storyline created by Next Gen Storylines and inquiryHub. Next Gen Storylines is an open-source resource that can be used by parents and teachers to implement student-driven learning. inquiryHub is a research-based curricula supporting Next Generation Science.