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Curriculum Materials

Standards Alignment

Disciplinary Core Ideas

LS2.A: Interdependent Relationships in Ecosystems (HS)

  • Ecosystems have carrying capacities, which are limits to the numbers of organisms and populations they can support. These limits result from such factors as the availability of living and nonliving resources and from such challenges such as predation, competition, and disease. Organisms would have the capacity to produce populations of great size were it not for the fact that environments and resources are finite. This fundamental tension affects the abundance (number of individuals) of species in any given ecosystem (HS-LS2-1).
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Science & Engineering Practices

Analyzing and Interpreting Data (HS)

  • Evaluate the impact of new data on a working explanation and/or model of a proposed process or system.
  • Engaging in Argument from Evidence (HS)
  • Construct  based on data and evidence.
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Crosscutting Concepts

Cause and Effect (HS)

  • Cause and effect relationships can be suggested and predicted for complex natural and human designed systems by examining what is known about smaller scale mechanisms within the system.
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Because certain types of bacteria can make humans sick, many people believe that having bacteria in food is always harmful. Throughout this task, students will gradually analyze new sources of data to revise working explanations of whether all bacteria are harmful for humans or if some bacteria can be used to prevent food from spoiling. First, students explore the food ecosystems of two samples of yogurt with different bacteria to figure out which types are harmful and then explore the environmental conditions that allow harmful and less harmful bacteria to thrive. Next, students investigate how the presence of a bacteria called lactobacillus can actually prevent harmful bacteria from forming on food, which they use to construct a final argument about how bacteria can actually be beneficial to humans by making food safer.