The unit builds toward the following NGSS Performance Expectations (PE):

• HS-LS2-1  Use mathematical and/or computational representations to support explanations of factors that affect carrying capacity of ecosystems at different scales.
• HS-LS2-2  Use mathematical representations to support and revise explanations based on evidence about factors affecting biodiversity and populations in ecosystems of different scales.
• HS-LS2-6  Evaluate the claims, evidence, and reasoning that the complex interactions in ecosystems maintain relatively consistent numbers and types of organisms in stable conditions, but changing conditions may result in a new ecosystem.
• HS-LS2-7  Design, evaluate, and refine a solution for reducing the impacts of human activities on the environment and biodiversity.
• HS-LS2-8  Evaluate the evidence for the role of group behavior on individual and species’ chances to survive and reproduce.
• HS-ESS3-3  Create a computational simulation to illustrate the relationships among management of natural resources, the sustainability of human populations, and biodiversity.
• HS-ETS1-3†  Evaluate a solution to a complex real-world problem based on prioritized criteria and trade-offs that account for a range of constraints, including cost, safety, reliability, and aesthetics as well as possible social, cultural, and environmental impacts.

†This performance expectation is developed across multiple courses.

LS2.A: Interdependent Relationships in Ecosystems

• 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.

LS2.C: Ecosystem Dynamics, Functioning, and Resilience

• A complex set of interactions within an ecosystem can keep its numbers and types of organisms relatively constant over long periods of time under stable conditions. If a modest biological or physical disturbance to an ecosystem occurs, it may return to its more or less original status (i.e., the ecosystem is resilient), as opposed to becoming a very different ecosystem. Extreme fluctuations in conditions or the size of any population, however, can challenge the functioning of ecosystems in terms of resources and habitat availability.
• Moreover, anthropogenic changes (induced by human activity) in the environment—including habitat destruction, pollution, introduction of invasive species, overexploitation, and climate change—can disrupt an ecosystem and threaten the survival of some species.

LS2.D: Social Interactions and Group Behavior

• Group behavior has evolved because membership can increase the chances of survival for individuals and their genetic relatives.

LS4.D: Biodiversity and Humans

• Biodiversity is increased by the formation of new species (speciation) and decreased by the loss of species (extinction). (secondary)
• Humans depend on the living world for the resources and other benefits provided by biodiversity. But human activity is also having adverse impacts on biodiversity through overpopulation, overexploitation, habitat destruction, pollution, introduction of invasive species, and climate change. Thus sustaining biodiversity so that ecosystem functioning and productivity are maintained is essential to supporting and enhancing life on Earth. Sustaining biodiversity also aids humanity by preserving landscapes of recreational or inspirational value. 

ESS3.C: Biodiversity and Humans

• The sustainability of human societies and the biodiversity that supports them requires responsible management of natural resources.

ETS1.B: Developing Possible Solutions

• When evaluating solutions it is important to take into account a range of constraints including cost, safety, reliability and aesthetics and to consider social, cultural and environmental impacts.

This unit intentionally develops students’ engagement in these practice elements:

• Developing and Using Models
  • 2.3 Develop, revise, and/or use a model based on evidence to illustrate and/or predict the relationships between systems or between components of a system. 
  • 2.4 Develop and/or use multiple types of models to provide mechanistic accounts and/or predict phenomena, and move flexibly between model types based on merits and limitations. 
  • 2.5 Develop a complex model that allows for manipulation and testing of a proposed process or system.
  • 2.6 Develop and/or use a model (including mathematical and computational) to generate data to support explanations, predict phenomena, analyze systems, and/or solve problems.
• Using Mathematics and Computational Thinking:
  • 5.2 Use mathematical, computational, and/or algorithmic representations of phenomena or design solutions to describe and/or support claims and/or explanations. 
• Construction Explanations:
  • 6.5 Design, evaluate, and/or refine a solution to a complex real-world problem, based on scientific knowledge, student-generated sources of evidence, prioritized criteria, and trade off considerations.

The following practices are also key to the sensemaking in this unit:

• Asking Questions and Defining Problems
  • 1.1 Ask questions that arise from careful observation of phenomena, or unexpected results, to clarify and/or seek additional information.
• Analyzing and Interpreting Data
  • 4.1 Analyze data using tools, technologies, and/or models (e.g., computational, mathematical) in order to make valid and reliable scientific claims or determine an optimal design solution. 
• Obtaining, Evaluating and Communicating Information
  • 8.1 Critically read scientific literature adapted for classroom use to determine the central ideas or conclusions and/or to obtain scientific and/or technical information to summarize complex evidence, concepts, processes, or information presented in a text by paraphrasing them in simpler but still accurate terms.
  • 8.2 Compare, integrate and evaluate sources of information presented in different media or formats (e.g., visually, quantitatively) as well as in words in order to address a scientific question or solve a problem.
  • 8.5 Gather, read, and evaluate scientific and/or technical information from multiple authoritative sources, assessing the evidence and usefulness of each source.

This unit intentionally develops students’ engagement in these crosscutting concept elements:

• Stability and Change:
  • 7.1 Much of science deals with constructing explanations of how things change and how they remain stable.  
  • 7.2 Change and rates of change can be quantified and modeled over very short or very long periods of time. Some system changes are irreversible. 
  • 7.4 Systems can be designed for greater or lesser stability.
• Systems and System Models:
  • 4.1 Systems can be designed to do specific tasks.  
  • 4.2 When investigating or describing a system, the boundaries and initial conditions of the system need to be defined and their inputs and outputs analyzed and described using models.
  • 4.4 Models can be used to predict the behavior of a system, but these predictions have limited precision and reliability due to the assumptions and approximations inherent in models.

The following crosscutting concepts are also key to the sensemaking in this unit:

• Patterns
  • 1.4 Mathematical representations are needed to identify some patterns.  
  • 1.5 Empirical evidence is needed to identify patterns.
• Cause and Effect
  • 2.2 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. 
• Scale, Proportion, and Quantity
  • 3.1 The significance of a phenomenon is dependent on the scale, proportion, and quantity at which it occurs. 

Which elements of the Nature of Science (NOS) are developed in the unit?

• Science knowledge is based on empirical evidence. (NOS-SEP)
• Science arguments are strengthened by multiple lines of evidence supporting a single explanation. (NOS-SEP)
• Many decisions are not made using science alone, but rely on social and cultural contexts to resolve issues. (NOS-CCC)
• Science is both a body of knowledge that represents a current understanding of natural systems and the processes used to refine, elaborate, revise, and extend this knowledge. (NOS-CCC)

How are they developed?

• Students engage with empirical evidence in the form of scientific articles, data, and images throughout the unit.
• Students gather multiple types of evidence (e.g. historical data,  kinesthetic modeling, simulation-based data, data generated from agent based models, etc.) to support their ideas.
• Students hear from a variety of perspectives as they consider whether the proposed solutions would have a positive impact.
• Students use their understandings gained from exploring the Serengeti as both an ecosystem and successful conservation plan to evaluate the success of the conservation plan for their conservation profile.

In the anchoring phenomenon, students explore conservation in the context of the 30 by 30 Initiative which aims to conserve 30 percent of US lands and waters by 2030. Students learn about the initiative and brainstorm criteria that people use when deciding to protect lands and waters. Students draw on their own experiences and investigate four different conservation profiles in the US. They develop initial models to explain the system and why humans wanted to protect it. They generate questions that they need to answer to be able to fully explain their models. Students also notice unique and common features in each case and are motivated to learn more about how ecosystems work and how we can use what we learn to protect them.

This phenomenon gives students a real world context for thinking about ecosystems and their protection while at the same time helping them recognize that often, what we learn about one ecosystem can be applied to another. This motivates the class to investigate a single case together, the Serengeti. The Serengeti was chosen as the focus of the majority of the lessons because it has been studied extensively for over 70 years and many long term, comprehensive data sets are available for students to investigate. In addition, the Serengeti phenomenon generated high student interest across racial and gender identities in a national survey.

This unit is the first in the OpenSciEd High School Biology course sequence.

The unit is organized into three lesson sets. Lesson Set 1 (Lessons 1-6) focuses on the populations within an ecosystem and the different factors that affect them. It ends with a transfer task about African wild dogs. Lesson Set 2 (Lessons 7-8) helps students begin to unravel the complexity of ecosystems as they discover the importance of keystone species in terms of ecosystem stability and resilience. Lesson Set 3 (Lessons 9-11) helps students use their understanding of ecosystems to evaluate their conservation in systems in the US. This unit culminates with a transfer task where they apply all of their understandings to the American Prairie and its conservation.

This is the first unit of the High School Biology Course in the OpenSciEd Scope and Sequence. Given this placement, several modifications would need to be made if teaching this unit later in the year course. These include the following adjustments:

• As the first unit of the year, the lessons devote more time to developing and supporting classroom agreements. If the unit were to be taught later in the year, classroom community would need to be addressed elsewhere. 
• The unit introduces students to a key assessment routine, transfer tasks, that are a key part of the OpenSciEd program’s assessment system. In this unit, students are introduced to the routine and its purpose. Their engagement with this first transfer task is scaffolded through collaborative group work, peer and teacher feedback. Students also get to know the rubric structure for the task to increase their agency in the assessment process. If taught out of order, students would need to be introduced to transfer tasks in the first unit in which they experienced them.
• Developing and using models is a key practice in this unit and the OpenSciEd program. This unit introduces students to the practice of developing models by first including components and interactions in Lesson 1. In subsequent lessons students explain the interactions in their models as mechanisms. Finally, students use their models to predict outcomes. If taught out of order, students would benefit from a scaffolded approach to developing their modeling practice.

The following are example options to shorten or condense parts of the unit without eliminating important sensemaking for students:

• Lesson 2: Read the History of Serengeti aloud as a class instead of reading in small groups and then discussing again as a class.
• Lesson 10: Instead of having each group present their conservation profiles and plans to the class, a gallery walk of the presentations may help to streamline this portion of the lesson.

To extend or enhance the unit, consider the following:

• Lesson 6: The African wild dog pack in Liwonde had puppies! For updates on the pack, share the following resources:
  • Video of how they moved African wild dogs https://www.youtube.com/watch?v=S1m00A6koE0
  • Images of the pups born in Liwonde after relocation https://www.facebook.com/watch/?v=605291120734360
  • Updates on Liwonde National Park https://www.africanparks.org/the-parks/liwonde
• Lesson 7: Have students write algorithms for multiple agents.
• Lesson 8: Create additional Serengeti Component Articles for components your students’ mention but are not already included in the lesson.
• Lesson 8: Engage the whole class in the citizen science project, Snapshot Serengeti. Found at https://www.snapshotserengeti.org/.

• Kate Henson, Revision Unit Lead, University of Colorado Boulder
• Will Lindsay, Field Test Unit Lead, University of Colorado Boulder
• Clarissa Deverel-Rico, Writer, University of Colorado Boulder
• Sara Krauskopf, Writer, University of Colorado Boulder
• DeAnna Lee-Rivers, Writer, University of Colorado Boulder
• Simon Raphael Mduma, Consultant Expert, Wildlife Biologist
• Celeste Moreno, Writer, University of Colorado Boulder
• Jamie Deutch Noll, Writer, BSCS Science Learning
• Kathryn Ribay, Writer, San Jose State University
• Jessica Schwarz, Consultant Expert, Roaring Fork Schools
• Anthony R.E. Sinclair, Consultant Expert, University of British Columbia 
• Wayne Wright, Writer, University of Colorado Boulder

We appreciate the support of two of our partners – ECA Science Kit Services and BSCS Science Learning– who provided kits for OpenSciEd facilitators and teachers in classrooms as part of the OpenSciEd field test.

University of Colorado Boulder

• Madison Hammer, Production Manager
• Amanda Howard, Copy Editor
• Erin Howe, Project Manager

An integral component of OpenSciEd’s development process is external validation of alignment to the Next Generation Science Standards by NextGenScience’s Science Peer Review Panel using the EQuIP Rubric for Science. We are proud that this unit has earned the highest score available and has been awarded the NGSS Design Badge. You can find additional information and read this unit’s review on the nextgenscience.org website.