Unit Overview
7.5 Ecosystem Dynamics

How does changing an ecosystem affect what lives there?

Unit Summary

This unit on ecosystem dynamics and biodiversity begins with students reading headlines that claim that the future of orangutans is in peril and that the purchasing of chocolate may be the cause. Students then examine the ingredients in popular chocolate candies and learn that one of these ingredients--palm oil--is grown on farms near the rainforest where orangutans live. This prompts students to develop initial models to explain how buying candy could impact orangutans.

Students spend the first lesson set better understanding the complexity of the problem, which cannot be solved with simple solutions. They will figure out that palm oil is derived from the oil palm trees that grow near the equator, and that these trees are both land-efficient and provide stable income for farmers, factors that make finding a solution to the palm oil problem more challenging. Students will establish the need for a better design for oil palm farms, which will support both orangutans and farmers. The final set of lessons engage students in investigations of alternative approaches to growing food compared to large-scale monocrop farms. Students work to design an oil palm farm that simultaneously supports orangutan populations and the income of farmers and community members.

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Orangutan Population Model – Classroom and Remote Use

In this simulation, individual orangutans compete with each other for food resources. Orangutans reproduce when they have enough energy and die if their energy reaches zero. Students interpet line graphs of population size over a 5 year period for environmental conditions with normal, abundant, and scarce food availability for orangutans. This simulation is used in Lesson 9.

Orangutan Energy Model 2 – Remote or Absent Students

In this simulation, individual orangutans compete with each other for food resources. It is intended for remote learning or kids who are absent. Students interpet a histogram of results for environmental conditions with normal, abundant, and scarce food availability for orangutans. This simulation is used as an alternative for Lesson 8.

Orangutan Energy Model 1 – Classroom Use

In this simulation, individual orangutans compete with each other for food resources while students cheer them on. It is intended for in-person instruction. Students build a histogram of class results for environmental conditions with normal, abundant, and scarce food availability for orangutans. This simulation is used in Lesson 8.

Collaborative Oil Palm Model

In this simulation, students take on roles to redesign the land in ways that support both farmers and orangutans. They test designs to determine which designs result in stable orangutan populations while also meeting the economic needs of people who live in the area. This simulation is used in Lesson 17.

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Additional Unit Information

Building Toward the Following Standards and Practices
Performance Expectations
  • MS-LS2-1: Analyze and interpret data to provide evidence for the effects of resource availability on organisms and populations of organisms in an ecosystem.
  • MS-LS2-4: Construct an argument supported by empirical evidence that changes to physical or biological components of an ecosystem affect populations.
  • MS-LS2-2: Construct an explanation that predicts patterns of interactions among organisms across multiple ecosystems.
  • MS-LS2-5: Evaluate competing design solutions for maintaining biodiversity and ecosystem services.
  • MS-ESS3-3: Apply scientific principles to design a method for monitoring and minimizing a human impact on the environment.
  • MS-ETS1-1: Define the criteria and constraints of a design problem with sufficient precision to ensure a successful solution, taking into account relevant scientific principles and potential impacts on people and the natural environment that may limit possible solutions.
Disciplinary Core Ideas
  • LS2.A: Organisms, and populations of organisms, are dependent on their environmental interactions both with other living things and with non-living factors. Students investigate how organisms (see Lessons 8) and populations of organisms (Lessons 7, 9-12) depend on interactions with other populations particularly as they search for food resources. Students focus on plant interactions with non-living factors in Lesson 3.  
  • LS2.A: In any ecosystem, organisms and populations with similar requirements for food, water, oxygen, or other resources may compete with each other for limited resources, access to which consequently constrains their growth and reproduction. Students investigate competition between orangutans in a simulation in Lesson 8 and circle back to competition in Lesson 13.
  • LS2.A: Growth of organisms and population increases are limited by access to resources. Students build these ideas through simulations and additional case studies across Lessons 8-11.
  • LS2.A: Similarly, predatory interactions may reduce the number of organisms or eliminate whole populations of organisms. Mutually beneficial interactions, in contrast, may become so interdependent that each organism requires the other for survival. Although the species involved in these competitive, predatory, and mutually beneficial interactions vary across ecosystems, the patterns of interactions of organisms with their environments, both living and non-living, are shared. Students model different interactions in the rainforest and oil palm systems, including predation, competition, and mutualism between orangutans and fruit tree populations (see Lessons 11-13).
  • LS2.C: Ecosystems are dynamic in nature; their characteristics can vary over time. Disruptions to any physical or biological component of an ecosystem can lead to shifts in all its populations. Students model different disruption scenarios and predict how those disruptions would shift populations. Students hear from farmers about the strategies they employ to protect themselves from disruptions (see Lessons 13, 15, 16).
  • LS2.C: Biodiversity describes the variety of species found in Earth’s terrestrial and oceanic ecosystems. The completeness or integrity of an ecosystem’s biodiversity is often used as a measure of its health. Students compare rainforest systems to oil palm systems in terms of the biodiversity found in each system (see Lesson 13). Students learn that farmers are interested in supporting biodiversity in Lesson 14.
  • LS4.D: Changes in biodiversity can influence humans’ resources, such as food, energy, and medicines, as well as ecosystem services that humans rely on—for example, water purification and recycling. Students figure out that people engage with different ways to grow food compared to monocrop in order to obtain different benefits, or services (see Lessons 15-16).
  • ESS3.C: Human activities have significantly altered the biosphere, sometimes damaging or destroying natural habitats and causing the extinction of other species. But changes to Earth’s environments can have different impacts (negative and positive) for different living things. Students focus on understanding the problem, which involves humans altering the biosphere in ways that negatively impact orangutans (Lessons 2-4) and alterations in their own communities (Lessons 5). Students also encounter ways humans farm for food that positively support biodiversity in Lesson 14.
  • ETS1.A: The more precisely a design task’s criteria and constraints can be defined, the more likely it is that the designed solution will be successful. Specification of constraints includes consideration of scientific principles and other relevant knowledge that are likely to limit possible solutions. Students use criteria and constraints, based on the science and engineering ideas developed in the unit, with a particular attention to what land-use strategies work for different stakeholders and the limits of their application. Students make their first pass at criteria and constraints in Lesson 6 and revisit them to make them more precise in Lesson 17. Students evaluate design based on criteria and constraints in Lesson 18.
Focal Science & Engineering Practices
  • Asking Questions and Defining Problems: This unit is anchored by a complex socioscientific issue. Students’ initial questions on the DQB lead them to investigate simple fixes to a complex problem. The first lesson set serves to complicate the problem for them, culminating in defining it more clearly later in Lesson 6. Students define a design problem that can be solved through the development of a system, but a designed system that is limited by both scientific and social factors.
  • Developing and Using Models: Students develop new understandings about how to use a computer model to generate data to test ideas about population dynamics in the rainforest and farm designs. They evaluate the limitations of the computer model in comparison to the complex real-world systems the model is representing.
  • Planning and Carrying Out Investigations: Students engage in planning and carrying out investigations with independent and control variables in a computer simulation. They use the simulation in the unit as a way to collect data and produce data about design solutions and proposed systems under a range of conditions.
    Mathematics and Computation Thinking: Students calculate ratios of orangutans to land area to understand population density. They characterize and use graphical representations of populations over time to draw conclusions about resource availability and farm designs. The lesson 10 assessment on Monarch butterflies allows for assessment of this practice.
Focal Crosscutting Concepts
  • Cause and Effect: Cause and effect is a lens students apply throughout the unit, focusing on establishing cause and effect relationships in order to predict phenomena. Students use cause and effect in the context of natural systems and in their designs land-use systems.
  • System and System Models: Students develop system models to allow them to understand the different components and interactions occurring within the system. They discuss limitations of their system models for representing the complexity of the real-world systems (e.g., simulations representing limited components and interactions).
  • Stability and Change: Stability and change is a consistent lens students apply throughout the unit as they make sense of small changes in the system that have large impacts, as well as sudden and gradual changes over time. They look to stabilize orangutan populations and farmers income in their final designs.
Unit Information
How will I need to modify the unit if taught out of sequence?

This is the fifth unit in 7th grade in the OpenSciEd Scope and Sequence. Given this placement, several modifications would need to be made if teaching this unit earlier or later in the middle-school curriculum. These include:

  • If taught before the OpenSciEd Unit 7.1: How can we make something new that was not there before? (Bath Bombs Unit) or at the start of the school year, supplemental teaching of classroom norms, setting up the Driving Question Board, and asking open-ended and testable questions would need to be added. (These supports are built into the Bath Bombs Unit)
  • If taught before the Maple Syrup Unit, supplemental teaching of matter cycling between organisms and food webs would be required. In particular, students having experienced the Maple Syrup Unit will want to immediately investigate the ingredients in candy during the anchor lesson because students traced many ingredients back to plants in that unit. This may not be the case for students who have not experienced the Maple Syrup Unit, so the motivation to look at candy ingredients on day 1 of Lesson 1 may need additional support from you. The unit also relies on students having a recent learning experience around producers and consumers and the interconnection between the two in a food chain. This is particularly important for Lessons 11-13. Food webs are taught in 5th grade and students can work from this level of understanding, if needed. Lastly, Lesson 3 expects that students can readily identify the conditions that plants need to grow. The lesson has students briefly articulate these conditions so that students use most of the instructional time to identify growing conditions for oil palm plants. Additional time may need to be spent in this lesson if students have not learned about plant growth (MS-LS1-6).
  • This unit is highly dependent on 6th-grade math concepts. If this unit is taught in 6th grade, it is suggested to work very closely with a 6th grade math teacher to understand when students will learn the mathematical concepts and process (listed below) so that this unit can reinforce those concepts in a real-world problem context but not come before students have developed these ideas in their math classes (or working in conjunction with math and science simultaneously).
What mathematics is required to fully access the unit’s learning experiences?

During Lesson Set 2, students will engage in population thinking, rate and ratio reasoning, and encounter many graphical representations of data (e.g., line graphs, histograms) that they will need to interpret. They will calculate ratios in Lesson 7, create histograms together in Lesson 8, and interpret single data points in a distribution during both Lessons 8 and 9. Students will also work with the concept of “trend” in Lessons 9 and 10. Prerequisite math concepts that may be helpful include:

  • CCSS.Math.Content.6.RP.A.1 Understand the concept of a ratio and use ratio language to describe a ratio relationship between two quantities.
  • CCSS.Math.Content.6.RP.A.2 Understand the concept of a unit rate a/b associated with a ratio a:b with b ≠ 0, and use rate language in the context of a ratio relationship.
  • CCSS.Math.Content.6.RP.A.3 Use ratio and rate reasoning to solve real-world and mathematical problems.
  • CCSS.Math.Content.6.RP.A.3.c Find a percent of a quantity as a rate per 100.
  • CCSS.Math.Content.6.RP.A.3.d Use ratio reasoning to convert measurement units; manipulate and transform units appropriately when multiplying or dividing quantities.
  • CCSS.Math.Content.6.NS.B.2 Fluently divide multi-digit numbers using the standard algorithm.
  • CCSS.Math.Content.6.NS.B.3 Fluently add, subtract, multiply, and divide multi-digit decimals using the standard algorithm for each operation.
  • CCSS.Math.Content.6.NS.C.5 Understand that positive and negative numbers are used together to describe quantities having opposite directions or values.
  • CCSS.Math.Content.6.SP.A.1 Recognize a statistical question as one that anticipates variability in the data related to the question and accounts for it in the answers.
  • CCSS.Math.Content.6.SP.A.2 Understand that a set of data collected to answer a statistical question has a distribution, which can be described by its center, spread, and overall shape.
  • CCSS.Math.Content.6.SP.B.5.c Giving quantitative measures of center (median and/or mean) and variability (interquartile range and/or mean absolute deviation), as well as describing any overall pattern and any striking deviations from the overall pattern, with reference to the context in which the data were gathered.
What additional strategies are available to support equitable science learning in this unit?

OpenSciEd units are designed to promote equitable access to high-quality science learning experiences for all students. Each unit includes strategies which are integrated throughout the OpenSciEd routines and are intended to increase relevance and provide access to science learning for all students. OpenSciEd units support these equity goals through several specific strategies such as: 1) integrating Universal Design for Learning (UDL) Principles during the unit design process to reduce potential barriers and provide more accessible ways in which students can engage in learning experiences; 2) developing and supporting classroom norms that provide a safe learning culture, 3) supporting classroom discourse to promote students in developing, sharing, and revising their ideas, and 4) specific strategies to supporting emerging multilingual students in science classrooms.

Many of these strategies are discussed in the teacher guides in sidebar callout boxes titled “Attending to Equity” and subheadings such as “Supporting Emerging Multilingual Learners” or “Supporting Universal Design for Learning.” Other callout boxes with strategies are found as “Additional Guidance”, “Alternate Activity,” and “Key Ideas” and various discussion callouts. Finally, each unit includes the development of a Word Wall as part of students’ routines to “earning” or “encountering” scientific language.

For more information about each of these different strategies with example artifacts, please see the OpenSciEd Teacher Handbook.

Unit Acknowledgements
Unit Development Team
  • Lindsey Mohan, Unit Lead, BSCS Science Learning
  • Renee Affolter, Writer, Reviewer, & PD Design, Boston College
  • Kate Cook Whitt, Writer, Maine Math and Science Alliance
  • Candice Guy-Gaytán, Writer, BSCS Science Learning
  • Emily Harris, Writer, BSCS Science Learning
  • Ty Scaletta, Writer, Pilot teacher, Chicago Public Schools
  • Guy Ollison, Writer, BSCS Science Learning
  • Barbara Taylor, Writer, Charles A. Center at UT-Austin
  • Michael Novak, Conceptual design, Northwestern University
  • Heather Young, Sim Developer, Oregon Public Broadcasting
  • Cathie Stimac, Sim Design, Oregon Public Broadcasting
  • Charles Hickey, Pilot teacher, Weymouth Public Schools
  • Jennifer Loud, Pilot teacher, Weymouth Public Schools
  • Julie Callanan, Pilot teacher, Advisor, Framingham Public Schools
  • Katie Van Horne, Assessment Specialist
  • Cindy Passmore, Unit Advisory Chair, UC-Davis
  • Steve Babcock, Advisor, Louisiana State University
  • Karla White, Teacher Advisor, Bethany Public Schools
  • Dr. Cheryl Knott, Natalie Robinson, and Dr. Andrea Blackburn from Boston University and the Gunung Palung Orangutan Conservation Program
  • Dr. Rodolfo Dirzo, Stanford University
Production Team

BSCS Science Learning

  • Rachel Paul, Copyeditor, Independent Contractor
  • Natalie Giarratano, Copyeditor (field test), Independent Contractor
  • Kate Herman, Copyeditor, Independent Contractor
  • Stacey Luce, Editorial Production Lead Valerie Maltese, Communications and Advancement Manager
  • Renee DeVaul, Project Manager
  • Chris Moraine, Multimedia Graphic Designer
  • Kate Chambers, Multimedia Graphic Designer
Unit External Evaluation
NextGenScience’s Science Peer Review Panel

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 about the EQuIP rubric and the peer review process at the nextgenscience.org website.