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Ecosystems | Unit Goals

Carbon TIME: Ecosystems Unit

Ecosystems is one of the six Carbon TIME units. If you are new to teaching Carbon TIME, read the Carbon TIME FAQ: Which Units Should I Teach.

The Ecosystems Unit supports students in using core disciplinary ideas, science practices, and crosscutting concepts to develop scientific explanations of how different ecosystems transform matter and energy as the organisms in them live, grow, and die.

Follow these steps to get ready to teach the Ecosystems Unit

Lead Editor for 2019 Version

Kirsten D. Edwards, Department of Teacher Education, Michigan State University

Principal Authors

Kirsten D. Edwards, Department of Teacher Education, Michigan State University

Joyce Parker, Earth and Environmental Sciences, Michigan State University

Craig Kohn, Department of Teacher Education, Michigan State University

Wendy Johnson, Kentwood Public Schools

Jenny Dauer, University of Nebraska, Lincoln

Elizabeth Tompkins, Michigan State University

Charles W. “Andy” Anderson, Department of Teacher Education, Michigan State University

Contributing Authors

Sarah Bodbyl Roels, Beth Covitt, Elizabeth Xeng de los Santos, Jennifer Doherty, Allison Freed, Bonnie McGill, Lindsey Mohan, Emily Scott, Carly Seeterlin, Nick Verbanic, Alex Walus


Craig Douglas

This research is supported in part by grants from the National Science Foundation: A Learning Progression-based System for Promoting Understanding of Carbon-transforming Processes (DRL 1020187) and Sustaining Responsive and Rigorous Teaching Based on Carbon TIME (NSF 1440988). Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation or the United States Department of Energy.

This unit is also available online at Contact the MSU Environmental Literacy Program for more information:

The Driving Question

The Ecosystems Unit starts by asking students to express their ideas about the driving question about an anchoring phenomenon, “How many foxes can live in a meadow?”

Carbon is the key! In the unit, students learn to tell the story of how matter and energy are transformed as they move through ecosystems. A particularly powerful strategy for explaining how ecosystems transform matter and energy involves tracing carbon atoms. For more information about the Next Generation Science Standards
disciplinary core ideas included in this unit see the sections on the Large Scale Four Questions below and the Unit Goals.

Research base. This unit is based on learning progression research that describes the resources that students bring to learning about plants and the barriers to understanding that they must overcome. It is organized around an instructional model that engages students in three-dimensional practices.

Before beginning the Ecosystems Unit, you need to decide what to teach and importantly, what not to teach! Use this page to choose the unit sequence that’s most appropriate for your students.

Some activities are TWO-TURTLE ACTIVITIES (), which place a higher demand on students. Decide whether the higher demand required by these activities will be useful or distracting for your students. The Carbon TIME Turtle Trails Document document provides further info about choices for making units more or less demanding, depending on your students’ needs.

Unless otherwise noted in the table below, all activities in the unit should be taught.

Ecosystems Unit Sequence and Decisions Table

Here, we present two ways to think about how lessons are sequenced in the Ecosystems Unit. The Instructional Model, immediately below, emphasizes how students take on roles of questioner, investigator, and explainer to learn and apply scientific models they can use to answer the driving question. Further below, the Unit Storyline Chart highlights the central question, activity, and answer that students engage with in each lesson of the Ecosystems Unit.

Instructional Model

Like all Carbon TIME units, this unit follows an Instructional Model (IM) designed to support teaching that helps students achieve mastery at answering the driving question through use of disciplinary content, science practices, and crosscutting concepts. To learn more about this design, see the Carbon TIME Instructional Model.

During the inquiry portion of the unit (Lesson 2), the students move from making observations of a simulated meadow ecosystem to identifying patterns, eventually using these patterns to make evidence-based arguments. During the explanation portion of the unit (Lessons 3, 4, and 5), students makes connections across scales (from atomic-molecular scale to ecosystem scale) to explain patterns and changes in ecosystems. Across the unit, classroom discourse is a necessary part of three-dimensional Carbon TIME learning. The
Carbon TIME Discourse Routine
document provides guidance for scaffolding this discourse in lessons.

Decomposers Unit Map

The core of the Carbon TIME IM is the Observation, Patterns, Models (OPM) triangle, which summarizes key aspects to be attended to as the class engages in unit inquiry and explanation. The OPM triangle for the Ecosystems Unit, shown below, articulates the key observations students make during the unit investigation, the key patterns they identify through analyzing their investigation data, and the central scientific model that can be used to answer the unit’s driving question.

Observations, Patterns, Models, and Explanations in the Ecosystems Unit

Decomposers Instructional Model

The tables below show goals for this unit in two forms. A list of Next Generation Science Standards (NGSS) addressed by this unit is followed by a table showing specific target performances for each activity.

Next Generation Science Standards

The Next Generation Science Standards (NGSS) Performance Expectations that middle and high school students can achieve through completing the Ecosystems Unit are listed below. To read a discussion of how the Carbon TIME project is designed to help students achieve the performances represented in the NGSS, please see Three-dimensional Learning in Carbon TIME.

High School

  • Interdependent Relationships in Ecosystems. HS-LS2-1. Use mathematical and or computational representations to support explanations of factors that affect carrying capacity of ecosystems and different scales.

  • Interdependent Relationships in Ecosystems. HS-LS2-2. Use mathematical representations to support and revise explanations based on evidence about factors affecting biodiversity and populations in ecosystems at different scales.

  • Matter and Energy in Organisms and Ecosystems. HS-LS2-3. Construct and revise an explanation based on evidence for the cycling of matter and flow of energy in aerobic and anaerobic conditions.

  • Matter and Energy in Organisms and Ecosystems. HS-LS2-4. Use mathematical representations to support claims for the cycling of matter and flow of energy among organisms in an ecosystem.

  • Matter and Energy in Organisms and Ecosystems. HS-LS2-5: Develop a model to illustrate the role of photosynthesis and cellular respiration in the cycling of carbon among the biosphere, atmosphere, hydrosphere, and geosphere.

  • Earth’s Systems. HS-ESS2-6. Develop a quantitative model to describe the cycling of carbon among the hydrosphere, atmosphere, geosphere, and biosphere.

Middle School

  • Matter and Energy in Organisms and Ecosystems. MS-LS1-6. Construct a scientific explanation based on evidence for the role of photosynthesis in the cycling of matter and flow of energy in and out of organisms.

  • Matter and Energy in Organisms and Ecosystems. 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.

  • Interdependent Relationships in Ecosystems. MS-LS2-2. Construct an explanation that predicts patterns of interactions among organisms across multiple ecosystems.

  • Matter and Energy in Organisms and Ecosystems. MS-LS2-3. Develop a model to describe the cycling of matter and flow of energy among living and nonliving parts of an ecosystem.

  • Matter and Energy in Organisms and Ecosystems. MS-LS2-4. Construct an argument supported by empirical evidence that changes to physical or biological components of an ecosystem affect populations.

  • Earth’s Systems. MS-ESS2-1. Develop a model to describe the cycling of earth’s materials and the flow of energy that drives this process.

  • Human Impacts. MS-ESS3-4. Construct an argument supported by evidence for how increases in human population and per-capita consumption of natural resources impact Earth’s systems.

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