Unit 3 — Interdependent Relationships in Ecosystems
Description
Students build on their understandings of the transfer of matter and energy as they study patterns of interactions among organisms within an ecosystem. They consider biotic and abiotic factors in an ecosystem and the effects these factors have on a population. They construct explanations for the interactions in ecosystems and the scientific, economic, political, and social justifications used in making decisions about maintaining biodiversity in ecosystems. This unit includes a two-stage engineering design process where students evaluate different engineering ideas using systematic methods and then test and combine the best solutions.
Essential Questions
- What happens to ecosystems when the environment changes?
- How can a single change to an ecosystem disrupt the whole system?
- What limits the number and variety of living things in an ecosystem?
- How can we design solutions for maintaining biodiversity and ecosystem services?
Learning Objectives
- Construct an argument supported by empirical evidence that changes to physical or biological components of an ecosystem affect populations
- Evaluate competing design solutions for maintaining biodiversity and ecosystem services
- Define criteria and constraints of a design problem with sufficient precision
- Analyze data from tests to determine similarities and differences among design solutions
- Recognize patterns in data about ecosystem changes and make warranted inferences
- Evaluate empirical evidence supporting arguments about ecosystem changes
Supplemental Resources
- Tradeoff matrices and comparison charts for evaluating design solutions
- Graphic organizers for analyzing ecosystem disruptions and population changes
- Data collection tables for recording biodiversity observations
- Printed images of different ecosystem types for comparative analysis
- Chart paper and markers for creating visual displays of design criteria and constraints
Engineering, Technology, and Applications of Science
Life Sciences
Students cite textual evidence from science and technical texts, write arguments and informative/explanatory texts focused on discipline-specific content, gather and evaluate information from multiple sources, and draw evidence from informational texts to support analysis and research across all units. Reading standards for science and technical texts (RST.6-8.1, RST.6-8.2, RST.6-8.7, RST.6-8.8, RST.6-8.9) and writing standards (WHST.6-8.1, WHST.6-8.2, WHST.6-8.7, WHST.6-8.8, WHST.6-8.9) are explicitly referenced throughout all units. Speaking and listening standards support collaborative discussions and multimedia presentations.
Students use ratio and rate reasoning, summarize numerical data sets, represent relationships between variables using graphs and equations, and apply mathematical practices including reasoning abstractly and modeling with mathematics. Mathematical standards 6.SP.A.2, 6.SP.B.4, 6.SP.B.5, 6.EE.C.9, 6.RP.A.3, and Standards for Mathematical Practice MP.2 and MP.4 are explicitly referenced across units to support data analysis, statistical reasoning, and quantitative thinking in science contexts.
Formative Assessments
- Students construct arguments about how ecosystem disruptions affect populations
- Students evaluate existing solutions for maintaining biodiversity
- Students develop mathematical models for testing designed systems
- Students distinguish facts from reasoned judgment and speculation in ecosystem texts
- Students compare biodiversity before and after ecosystem disruptions
Summative Assessment
Quiz (25 multiple choice/5 true-false questions), Test (45 MC/True-False questions), Ecosystem Design Project with multimedia presentation
Benchmark Assessment
— not configured —
Alternative Assessment
Students may demonstrate understanding through a guided oral explanation of ecosystem relationships and population effects, supported by visual aids such as labeled diagrams or food webs. For the design project, students may complete a simplified design proposal using sketches, audio recordings, or a graphic organizer instead of a full multimedia presentation, with teacher clarification questions used to assess reasoning.
IEP (Individualized Education Program)
For this unit's focus on argumentation, data analysis, and ecosystem concepts, students may benefit from graphic organizers that scaffold the relationship between evidence and claims, such as structured cause-and-effect frames for explaining how biotic and abiotic changes affect populations. Providing vocabulary support with visual definitions for key ecosystem terms will reduce cognitive load during reading-heavy tasks. For assessments, allowing oral responses or the use of text-to-speech tools ensures that content mastery—rather than reading or writing demands—is being measured. Breaking the engineering design project into clearly sequenced checkpoints with teacher feedback at each stage will support students in managing the complexity of a multi-part task.
Section 504
Students in this unit benefit from extended time on quizzes, tests, and the ecosystem design project, particularly given the volume of multiple-choice and true-false questions. Preferential seating near the front of the room supports focus during ecosystem discussions and multimedia presentations, and reduced-distraction testing environments should be arranged as needed. Printed copies of any directions, models, or data displays shown digitally will ensure consistent access to instructional content throughout the unit.
ELL / MLL
This unit introduces a dense set of content-specific terms—such as biodiversity, ecosystem services, biotic and abiotic factors, and population—so pre-teaching vocabulary with visual supports, labeled diagrams, and real-world images of ecosystems will build necessary background knowledge. Directions for investigations and the engineering design tasks should be given in short, clear steps, and students should be invited to explain tasks in their own words before beginning. Where possible, connecting ecosystem concepts to environments or regions familiar to students' home cultures and providing opportunities to discuss ideas with a partner before writing will support both comprehension and participation.
At Risk (RTI)
Students who need additional support entering this unit will benefit from connecting ecosystem concepts to familiar, observable examples before introducing more abstract relationships between populations and ecosystem changes. Reducing the complexity of data sets used during analysis tasks—while maintaining the core reasoning skill—allows students to practice making evidence-based arguments without being overwhelmed by volume. Chunking the ecosystem design project into smaller, clearly defined stages with frequent check-ins gives students manageable entry points and helps them build confidence as they progress toward the summative presentation.
Gifted & Talented
Students who quickly demonstrate mastery of ecosystem interactions and biodiversity concepts should be invited to examine real-world case studies involving contested environmental policy decisions, weighing the scientific, economic, and social trade-offs at play. The engineering design component offers a natural extension opportunity: students can develop more sophisticated models, introduce additional variables, or propose original design solutions that go beyond evaluating existing ones. Encouraging students to research a current or local ecological issue and present a multi-perspective argument—grounded in empirical evidence—deepens both their scientific reasoning and their understanding of how societal decisions about ecosystems are made.