Disruption in Ecosystems - Energy Flow in Ecosystems 2.4 & 2.5

Contributor: The Lawrence Hall of Science SEPUP Program , American Museum of Natural History

Type Category: Instructional Materials

Types: Lesson/Lesson Plan

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.


These two lessons (Chapter 2 Lesson 4 and Lesson 5) are part of a unit developed by the American Museum of Natural History, the Lawrence Hall of Science SEPUP Program, and the University of Connecticut. The unit follows the 5E model (Engage, Explore, Explain, Elaborate, and Evaluate) to help engage students in making sense of the cycle of matter and flow of energy in an ecosystem. In the previous lesson (2.3) students learn that matter cycles between biotic and abiotic components. In these two lessons, students continue to build on this understanding and add the concept of energy flow to their food web model. Students obtain information by reading scientific findings from the Student Book, track the direction and quantity of energy flow using energy units, and revise their initial model. Students also revisit the Anticipation Guide from the previous lesson to reflect on how their thinking has changed. The Teacher Guide, Student Book, and student handouts/worksheets for this unit can be downloaded in a zip file from the Achieve website Quality Examples of Science Lessons and Units.

Intended Audience
Educator and learner

Educational Level
Middle School


Access Restrictions
Free access - The right to view and/or download material without financial, registration, or excessive advertising barriers.

Performance Expectation

MS-LS2-3  Develop a model to describe the cycling of matter and flow of energy among living and nonliving parts of an ecosystem.

Clarification Statement:

Emphasis is on describing the conservation of matter and flow of energy into and out of various ecosystems, and on defining the boundaries of the system.

Assessment Boundary:

Assessment does not include the use of chemical reactions to describe the processes.

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

Comments about Including the Performance Expectation

Developing models is the central focus of this learning segment. In Lesson 2.3, students learn that the Sun is the primary source of energy for producers, that plants convert light energy into chemical energy through photosynthesis, and that animals and decomposers obtain this chemical energy through food. All of these lead students to the idea that energy flows in one direction in an ecosystem. Students then add red arrows to their food web model to represent the flow of energy between living organisms. In Lesson 2.4-2.5, students develop a physical model to track the distribution of energy and learn about energy pyramids. Students add onto their model that energy is released to the environment as heat and that it flows between abiotic and biotic components in an ecosystem. Teachers can incorporate more hands-on labs about energy pyramids such as the Root Beer Activity (http://www.engr.sjsu.edu/tanagnos/Ecology/Root_Beer_Activity.doc ) to help students develop a concrete understanding of these concepts.

Science and Engineering Practice

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

Comments about Including the Science and Engineering Practice

Throughout this learning segment students have multiple opportunities to revise their initial model and add new information. For example, at the beginning of Lesson 2.5 students evaluate possible models for energy flow among living organisms. After reading a series of scientific findings, students make changes to reflect the most accurate model of energy flow. It is helpful to read the passage under "More Information - Scientific Representations" in the teacher guide (p56). It can be challenging for students to incorporate information from the reading into scientific representations so teachers could model this process by encouraging students to think out loud and visualize the text. Limitations of the model such as simplification of ideas or variation in scale are mentioned and should be explored with the class.

Disciplinary Core Idea

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

Comments about Including the Disciplinary Core Idea

In Lesson 2.3 students learn about how matter cycles between organisms by adding blue arrows to represent matter in their food web model. Students focus on energy flow and add red arrows to represent energy. Students also learn that chemical energy is converted into heat energy and that heat is released into the environment and cannot return to the biotic components of the ecosystem. At the end of this chapter, students are able to distinguish the movement of energy and matter in their model. They explain why energy "flows" and matter "cycles" in an ecosystem. Additional learning activities such as “Flow of Energy and Matter through Ecosystems” (https://www.khanacademy.org/science/high-school-biology/hs-ecology/trophic-levels/v/flow-of-energy-and-matter-through-ecosystems) by Khan Academy can also provide a good review of this concept.

Crosscutting Concept

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

Comments about Including the Crosscutting Concept

Throughout the lessons, students are encouraged to think about energy flow. Students first observe a compost bag and note that the composting matter produces heat. They add the Sun to their food web and understand that plants transfer energy from abiotic component (the Sun) to biotic components (consumers). Next, they apply this thinking to explain what happens to energy when a fire disrupts an ecosystem by providing captions to "Changes in a Forest Ecosystem" The forest fire scenario helps students see that fire releases energy rapidly through combustion instead of the slow release of energy during cellular respiration. In Part 2 of Lesson 2.5, it mentions that 90% of energy units go into the abiotic environment as heat energy. It is important to emphasize that organisms use most of the energy for growth, maintenance, and reproduction. During the chemical processes, the energy is transformed and released into the environment as heat.

Resource Quality

  • Alignment to the Dimensions of the NGSS: This is a three-dimensional lesson in which students use a model to make sense of how energy flows between biotic and abiotic components in an ecosystem. Students annotate the model by supporting it with evidence from reading and hands-on activities. Throughout the lessons, there are not many opportunities for students to generate their own questions. Teachers can ask the students to come up with additional questions after they revise the model. For example, students may wonder why there are not many top consumers in an ecosystem. This can be used as a driving question to help students make sense of energy pyramid in Lesson 2.5. Observing heat from the compost bag in Lesson 2.4 can also elicit questions from the students. This observation will motivate the students to figure out the phenomenon and make learning more relevant.
  • Instructional Supports: The Teacher Guide contains many instructional strategies to support student learning. For example, "four corners" is used to elicit students' prior knowledge in Lesson 2.5. Students walk to different corners of the room that represent their answers and explain their thinking. There are also strategies for Language Learners such as providing captions for the “Changes due to Fire in a Forest Ecosystem” worksheet. More differentiation is needed for gifted learners. Advanced readers can benefit from articles with higher Lexile level since the reading in the Scientific Findings are often short.
  • Monitoring Student Progress: The Teacher Guide is a great resource that provides guidance on when to elicit prior knowledge, what to listen for during discussions, and when to provide support if needed. Assessment checkpoints are embedded in the Analysis section with standards alignment. This helps teachers identify formative assessments and intervention opportunities. There are also answer keys to the analysis questions, Anticipation Guide, and Captions for “Changes due to Fire in a Forest Ecosystem”.
  • Quality of Technological Interactivity: - none -