Modeling Marine Food Webs and Human Impact

PBS Learning Media
Type Category
Instructional Materials
Lesson/Lesson Plan
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.



In this two-part lesson, students develop food webs and investigate human impacts on marine ecosystems. In Part I, students explore the ecological role of organisms in an ocean habitat and use information provided on Food Web Cards to develop food chains. In Part ll, students model the interconnected feeding relationships in the open ocean ecosystem by developing food webs and then using their food webs to explore the impact that different scenarios have on the ecosystem.

Intended Audience

Educator and learner
Educational Level
  • Grade 8
  • Grade 7
  • Grade 6
  • Middle School
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

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
The teacher materials provide informational cards for each of the species that is to be used in the food web. The lesson plan follows the 5E format. The teacher notes include suggested prompts on how to engage students in the topic. A number of video clips serve to pique students’ curiosity and motivate them to engage in the topic. The first part of the lesson could be supplemented with teacher-chosen materials in order to have students develop an interest in the topic and discover their own ideas, or to highlight an ecosystem that the students are more knowledgeable about. The lessons include good discussion questions for leading the class and getting the students to consider the movement of energy through the ecosystem. Students develop a food web using the information about each organism that is included on the cards. Food webs can serve as a scientific model since they show the energy flow in an ecosystem. It is important that the teacher ensures that students recognize the importance and impact of nonliving parts of the ecosystem, i.e. the sun and marine debris.

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
The students develop a food web from teacher provided materials. Food webs are a model that can be used to explain the energy flow in the ecosystem. If a teacher has additional time, the students can create a student-generated version. The teacher would have the students research species of a particular region, what their diet consists of and what the species’ predators are.

Disciplinary Core Ideas

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

Comments about Including the Disciplinary Core Idea
The teacher should be sure to include the ‘optional’ step (Day 2 in the Explore section) of labeling the organisms as producers, consumers, and decomposers so that students have a working vocabulary of the terms and recognize the hierarchy of the food web relationships. The teacher should make this more student centered and be sure that the students develop the understanding that matter is also transferred within the ecosystem. It is also important for the students to communicate their ideas, either in small groups or in whole-class format. By communicating their ideas and analyzing the scenarios that could result when a variable changes they will realize how small changes can make a big impact on an ecosystem. The teacher should supplement the discussion questions to encourage the students to explain their ideas and give evidence from the food webs that they created.

Crosscutting Concepts

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

Comments about Including the Crosscutting Concept
Although the food web does show the flow of energy and cycling of matter through an ecosystem, it is necessary to make this explicit to students. This could be accomplished by making 2 styles or colors of arrows to represent each, the matter and energy of the ecosystem. Students would include the arrows between the organisms, showing the cycling of matter and the flow of energy. The teacher should also be sure to discuss the importance of how energy flows through the ecosystem and matter cycles, as well as the ultimate source of the energy, the sun. If the students are ready for it, the teacher could also have them color code the substances that cycle through, including carbon, nitrogen, and oxygen.

Resource Quality

  • Alignment to the Dimensions of the NGSS: This resource addresses the 3 dimensions of the NGSS by having students create a model (foodweb) of a marine ecosystem, as they explore the disciplinary core idea how matter and energy are transferred within an ecosystem. The teacher should make sure to emphasize the crosscutting concept by having students track the flow of energy through the ecosystem. The teacher needs to be sure that the students are recognizing the importance of developing and using a model, such as the labeled diagram that shows the flow of energy and cycling of matter through the ecosystem. This model should be able to explain the phenomena that are occurring and allow the students to develop a conceptual understanding.

  • Instructional Supports: By beginning the 5E lesson with a series of questions and several short high-interest videos, this resource engages students in real world scenarios. The teacher can use the prompts and videos provided to create student interest and weave in connections to students’ own lives. The plans, videos and resources that are included are high quality. The discussion questions are adequate, but additional questions could be developed to allow the teacher to differentiate for each learner’s learning style and understanding.

  • Monitoring Student Progress: The student handouts and the discussion questions that are provided will allow the teacher to get an idea of student progress, but additional checkpoints could incorporate additional formative assessment. The teacher could incorporate ‘exit tickets’ that include an explanation of the energy sources or the effects of nonliving parts of the ecosystem.

  • Quality of Technological Interactivity: The videos play on a desktop computer, but should be checked for compatibility on specific devices prior to using them with students. They could alternatively be shown to the class with a projector if student devices do not play them.