CarbonTIME Ecosystems Unit

Contributor
Hannah Miller, Johnson State University; Jenny Dauer, University of Nebraska, Lincoln; Wendy Johnson, Marcos Gonzales, Charles W. “Andy” Anderson, Department of Teacher Education, Michigan State University
Type Category
Assessment Materials Instructional Materials
Types
Unit
Note
This resource, vetted by NSTA curators, is provided to teachers along with suggested modifications to make it more in line with the vision of the NGSS. While not considered to be "fully aligned," the resources and expert recommendations provide teachers with concrete examples and expert guidance using the EQuIP rubric to adapted existing resources. Read more here.

Reviews

Description

Ecosystems is one of six units in the Carbon: Transformations in Matter and Energy (Carbon TIME) curriculum, which was developed through an NSF-funded research collaboration focused on learning progressions to support environmental literacy.  These units were developed for middle and high school students. The units are designed in three groups, with each group increasing in scale.   The Ecosystems unit is one of two units at the large scale of ecosystems and global systems, and it is intended for students to complete one or both of these units.  Each large scale unit focuses on three questions: (1) Where are the carbon pools in the environment? (2) How are carbon atoms cycling among pools? and (3) What is happening to energy?   In the Ecosystems unit, students investigate a series of phenomena focused on biomass, matter and energy flow, and ecosystem services.  The highly guided sequence of five lessons in the unit helps students identify patterns from their observations, develop models for ecosystem functioning, and then apply those models to explain how humans depend on and affect ecosystems.  Extensive supporting infomation is provided within each lesson and on the reources page (http://carbontime.bscs.org/resources). The assessment site (http://ibis.colostate.edu/MSP/CTIME/Index.php) includes pre/posttests for each unit and for the overall curriculum.  The overview provided here (http://media.bscs.org/carbontime/files/unit_synopses.pdf) provides a helpful orientation to this complex resource.

Intended Audience

Educator
Educational Level
  • High School
Language
English
Access Restrictions

Free access with user action - The right to view and/or download material without financial barriers but users are required to register or experience some other low-barrier to use.

Performance Expectations

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.

Clarification Statement: Examples of models could include simulations and mathematical models.

Assessment Boundary: Assessment does not include the specific chemical steps of photosynthesis and respiration.

This resource is explicitly designed to build towards this performance expectation.

Comments about Including the Performance Expectation
Lesson 3 focused on the cycling of matter and flow of energy in ecosystems through the processes of photosynthesis and respiration. This lesson engages students in a game-based simulation of carbon cycling within an ecosystem and then asks students to develop an explanation that answers the three questions: (1) Where are the carbon pools in the environment? (2) How are carbon atoms cycling among pools? and (3) What is happening to energy? The unit does not address the roles of the hydrosphere and geosphere in carbon cycling, so teachers will need to plan additional learning experiences to address those aspects of the performance expectation.

HS-LS2-4 Use mathematical representations to support claims for the cycling of matter and flow of energy among organisms in an ecosystem

Clarification Statement: Emphasis is on using a mathematical model of stored energy in biomass to describe the transfer of energy from one trophic level to another and that matter and energy are conserved as matter cycles and energy flows through ecosystems. Emphasis is on atoms and molecules such as carbon, oxygen, hydrogen and nitrogen being conserved as they move through an ecosystem.

Assessment Boundary: Assessment is limited to proportional reasoning to describe the cycling of matter and flow of energy.

This resource is explicitly designed to build towards this performance expectation.

Comments about Including the Performance Expectation
In lesson 2, students use a meadow ecosystem simulation to generate a quantitative model of the biomass matter pyramid for this ecosystem. The pattern observed in this pyramid becomes the anchoring phenomenon for the unit. Students then use mathematical representations of carbon pools and fluxes resulting from photosynthesis and respiration to develop an explanation for the pattern in the biomass pyramid. The representations and models in this unit are primarily provided to students through interactive discussions. Teachers should be sure to follow the guidance for student questioning and discussion to ensure that students are actively engaged in the thought process that leads to their final explanation.

Science and Engineering Practices

This resource is explicitly designed to build towards this science and engineering practice.

Comments about Including the Science and Engineering Practice
Students do not develop their own models in this unit, but they use several models that are provided to them to illustrate the relationships between different carbon pools within ecosystems. Teachers may want to use targeted questioning (e.g., How does this model help us explain what is happening in the ecosystem? Is this model consistent with evidence we have collected? How can we apply this model to a different ecosystem? How is this model similar to and different from the real ecosystem?) to ensure that students are developing a meaningful understanding of these models. The discourse routine and assessment tips throughout the unit can help teachers monitor students’ understanding of the models they are using.

This resource is explicitly designed to build towards this science and engineering practice.

Comments about Including the Science and Engineering Practice
Students use graphs and numerical accounting to track biomass, carbon fluxes, and energy flow in various ecosystem models. These representations support claims about the causes for the structure of a biomass pyramid, the effects of disturbances on carbon fluxes, and the role of humans in food chains. Embedded supports, like the Evidence-Based Arguments Tool for Ecosystems (http://media.bscs.org/carbontime/ecosystems/worksheets_assessments/2.3_Evidence_Based_Arguments_Tool_for_Ecosystems.pdf) help students connect these mathematical representations to contextual explanations. Teachers should constantly reinforce the connection between calculations or graphing tasks and the meaning of these tasks within real ecosystems. The embedded teacher guidance and discussion prompts are helpful in making these connections.

Disciplinary Core Ideas

This resource is explicitly designed to build towards this disciplinary core idea.

Comments about Including the Disciplinary Core Idea
The unit focuses on the exchange of carbon among organisms, soil organic material, and the atmosphere through the biological process of photosynthesis and respiration. Activity 4.3 brings in the chemical process of combustion. The unit does not address physical, geological, and marine processes that are critical in global carbon cycling, so teachers will need to plan additional learning experiences to address those aspects of the disciplinary core idea.

This resource is explicitly designed to build towards this disciplinary core idea.

Comments about Including the Disciplinary Core Idea
Students develop this core idea in lessons 1-3 and then use it to explain ecosystem functions and humans’ role in ecosystems and food chains. The unit focuses exclusively on terrestrial ecosystems, so algae is not addressed as a producer. Teachers could extend lesson 5, which asks students to apply their learning to several ecosystems, to include one or more aquatic ecosystems that include algae. Teachers should refer to the three guiding questions, and the supporting rules, to check and reinforce students’ understanding of this disciplinary core idea.

Crosscutting Concepts

This resource is explicitly designed to build towards this crosscutting concept.

Comments about Including the Crosscutting Concept
Students will need to apply what they have learned about transformations of matter and energy in individual organisms to ecosystem-scale processes—to see how matter cycling and energy flow in ecosystems result from the atomic-molecular processes of photosynthesis, biosynthesis, digestion, and cellular respiration. This crosscutting concepts is also supported as students observe the “10% rule” in the biomass pyramid for the prairie ecosystem. Teachers can emphasize the connection to scale by linking this unit back to the “Zooming In” activities in the organism-scale units. This interactive tool (http://scaleofuniverse.com/) could facilitate such a discussion. Zooming from 10-1 to 104 will move the animation from small organisms to the scale of ecosystems, with Central Park as a good analog to the scale of the prairie ecosystem in this unit.

This resource is explicitly designed to build towards this crosscutting concept.

Comments about Including the Crosscutting Concept
Students use models throughout the unit to simulate interactions among carbon pools within ecosystems. Understanding of the ecosystem-level models in this unit is predicated on understanding of the organism-level models developed in previous Carbon TIME units. The Ecosystems unit asks students to connect their organismal models of photosynthesis and respiration to models of matter and energy flow in various ecosystems. The optional Activity 5.2 draws students’ attention to how real ecosystems are more complex than the models used in this unit. Completing this activity would provide an excellent opportunity to facilitate a discussion of the uses and limitations of scientific models.

This resource is explicitly designed to build towards this crosscutting concept.

Comments about Including the Crosscutting Concept
Ongoing reference to third guiding question for the unit, What is happening to energy?, will help students connect this crosscutting concept to the phenomena being investigated. The three questions are accompanied by supporting questions, rules to follow, and evidence that can be observed (http://media.bscs.org/carbontime/ecosystems/posters_spreadsheets/Three_Questions_Large_Scale_11_x_17_Poster.pdf). In particular, the rule that “Energy flows through Earth systems (but energy is never recycled)” makes this detail explicit throughout the unit. Students’ ability to recite this axiom, though, does not always translate into an ability to apply this concept productively. Thus, the authors suggest that teachers use targeted questions (e.g., What forms of energy are involved? What transformations occur? Does your claim match the rules for the energy question? Why or why not? How is your claim based on the evidence you collected?) to monitor students’ understanding of and ability to apply this crosscutting concept.

Resource Quality

  • Alignment to the Dimensions of the NGSS: The Carbon TIME units are explicitly designed for the NGSS, and the authors provide a unit-level map linking all units to specific performance expectations (http://media.bscs.org/carbontime/files/ngss_mapping.pdf). Teachers can check the NGSS alignment of specific lessons by clicking on the lesson title within a particular unit. Each unit follows a well-developed, research-based instructional model (http://media.bscs.org/carbontime/files/Carbon_TIME_Instructional_Model_8.11.16.pdf) that leads students to investigate, model, and explain phenomena related to the transformation of matter and energy in various carbon-transforming processes. Students engage in nearly all the science and engineering practices, and they repeatedly apply the crosscutting concepts of energy and matter and scale, proportion, and quantity. The Ecosystems unit first leads students to discover the pattern of biomass distribution with a simple food chain, and then asks students to develop an explanation for this pattern and for how humans both depend on and affect ecosystems. Some content is delivered through direct instruction supported by discussion, but this information is provided within the context of students developing explanations for phenomena. Teachers should use the discourse routine to facilitate interactive discussion in these situations. The instructional model mentioned above provides coherence within the unit, and the full collection of Carbon TIME units were developed in a coherent fashion, as described in the FAQ file (http://media.bscs.org/carbontime/files/Which_Units_Should_I_Teach_FAQ_1.19.16.pdf).

  • Instructional Supports: This unit is anchored by a simulation rather than an authentic phenomenon. Teachers could improve the relevance and authenticity of the unit by launching it with a locally important phenomenon. One example might be the effects of forage availability and predator populations on whitetail deer populations in the southeastern U.S. Carbon TIME units are built around a discourse routine (http://media.bscs.org/carbontime/files/Carbon_TIME_Discourse_Routine.pdf) that allows students to express and refine their ideas based on evidence and feedback. Each lesson includes specific talk and writing goals for students, with teacher talk strategies to support these goals. The accuracy and appropriateness of information in this unit is supported by the fact that the Carbon TIME units are based on learning progression research. Information about the learning progression (http://media.bscs.org/carbontime/files/abt201577402_Feature_Article_Parker_.pdf) and grade-appropriate content simplifications (http://media.bscs.org/carbontime/files/Carbon_TIME_Simplifications.pdf) are provided in supporting materials. Each unit includes three instructional pathways that call for explanations and performances below, on, or above grade level for high school students (http://media.bscs.org/carbontime/files/Turtles_07.05.16-1.pdf). Each lesson also includes suggestions for extending student learning. Student thinking is highly scaffolded early in each unit, and then this scaffolding is gradually removed as the unit concludes and students construct their own explanations.

  • Monitoring Student Progress: Process tools used throughout the units, such as the predictions tool for ant investigations (http://media.bscs.org/carbontime/plants/worksheets_assessments/3.1_GL_Predictions_Tool_for_Plant_Investigations.pdf), scaffold student thinking and provide direct evidence of three dimensional learning. Keys for these tools and assessment guidance are provided for each lesson, allowing the teacher to use these as embedded formative assessments to guide student learning. Assessment items were developed to be accessible to all levels of students, and the pre-/post-assessments were validated (http://media.bscs.org/carbontime/files/CarbonTIMEAssessmentValidation.pdf) with a sample of students that was diverse in terms of geography, grade level, and academic level. However, potential cultural bias of assessments is not addressed in supporting materials. All pre-/post-tests include assessment guidelines. Pre-/post-tests are available through the “Assessment Site” link on the Carbon TIME home page. Assessment links within units appear to require special permission to gain access.

  • Quality of Technological Interactivity: While the whole unit is not technology-based, it does center on the meadow ecosystem online simulation. The simulation is easy to use and supports the learning goals of the unit. Lesson 5 also calls for students to use Google Earth to observe changes over time in their local ecosystems. As the authors mention in the “Extending the Learning” section of that lesson, the Google Earth Engine timelapse viewer (https://earthengine.google.com/timelapse/) would enhance the interactivity and support the learning goals for that lesson.