We use cookies to provide you with a great user experience. By using our site, you accept our use of cookies. You can review our cookie and privacy policy here.
  • Service & Support

    Contact Us

    Our Customer Service team is available from 8am to 6:00pm, ET, Monday through Friday. Live chat is available from 8am to 5:30pm ET, Monday-Friday.

    Email Customer Service

    International Sales & Service

    We serve educators in more than 170 countries worldwide. Create a quote request on our website or contact our International Sales Team.

    International Ordering
  • Shopping

    Login or register now to maximize your savings and access profile information, order history, tracking, shopping lists, and more.

  • Quick
  • My Cart

    My Cart

    Your Shopping Cart is currently empty. Use Quick Order or Search to quickly add items to your order!

STC-Middle School™, STC3 Edition: Ecosystems and Their Interactions 1-Class Unit Kit



Grades 6–8. Unit Driving Question: How do organisms interact with one another and their environments?
Unit Highlight—As the unit opens, pond ecosystems and butterfly ecosystems provide the launching pad for learning how various elements of systems interact. During the unit's 11 lessons, students build models and work with simulations to learn how the food web, predation, genetics, and the energy pyramid affect ecosystems. By the end of the unit, students apply their learning to timely issues such as invasive species, runoff and its impact on drinking water, and landslides.

From the STC3 Edition, Ecosystems and Their Interactions addresses the performance expectations, and attendant science and engineering practices and crosscutting concepts, deemed appropriate for grades 6 through 8 by the Next Generation Science Standards® (NGSS). It allows students to develop an understanding of phenomena that influence the many different fields in the life sciences. By completing this unit, students and teachers alike will develop a better understanding of how the nonliving and living parts of an ecosystem interact.

Each lesson in this unit builds on the skills and concepts presented in previous lessons. As students progress through the unit, they take increasing responsibility for their own learning. Eventually, students plan and conduct their own procedures and analyze the results they obtain. Therefore, the unit should be taught in its entirety; it should not be used as a sourcebook of occasional experiments.

To structure and scaffold the development of students' knowledge, skills, and cognitive reasoning, this unit includes three primary lesson types: pre-assessment, skills and knowledge building, and assessment. The pre-assessment lesson allows educators to assess students' preconceptions, misconceptions, and skills. Skills and knowledge building lessons provide multiple opportunities for students to grow and learn through formative assessment. The assessment lesson includes both performance and written assessment activities that function together as a summative assessment of student learning.

This 1-Class Unit Kit comes with a Teacher Edition, teacher access to Carolinascienceonline.com, 16 reusable hardbound Student Guides (item #513603), student eBook access, and the materials needed for a teacher to teach up to 32 students per day. Note: Among the additional materials that will be needed but not supplied in the kit are 16 microscopes (we recommend item #591182).

The Ecosystems and Their Interactions unit addresses the following standards:
Next Generation Science Standards®
Performance Expectations

  • MS-LS1-5. Construct a scientific explanation based on evidence for how environmental and genetic factors influence the growth of organisms.
  • MS-LS1-6. Construct a scientific explanation based on evidence for the role of photosynthesis in the cycling of matter and flow of energy into and out of organisms.
  • 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.
  • MS-LS2-2. Construct an explanation that predicts patterns of interactions among organisms across multiple 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.
  • MS-LS2-4. Construct an argument supported by empirical evidence that changes to physical or biological components of an ecosystem affect populations.
  • MS-LS2-5. Evaluate competing design solutions for maintaining biodiversity and ecosystem services.
  • MS-LS4-4. Construct an explanation based on evidence that describes how genetic variations of traits in a population increase some individuals' probability of surviving and reproducing in a specific environment.
  • MS-LS4-6. Use mathematical representations to support explanations of how natural selection may lead to increases and decreases of specific traits in populations over time.
  • MS-ESS3-3. Apply scientific principles to design a method for monitoring and minimizing a human impact on the environment.
  • MS-ETS1-1. Define the criteria and constraints of a design problem with sufficient precision to ensure a successful solution, taking into account relevant scientific principles and potential impacts on people and the natural environment that may limit possible solutions.
  • MS-ETS1-2. Evaluate competing design solutions using a systematic process to determine how well they meet the criteria and constraints of the problem.

Disciplinary Core Ideas

  • LS1.B: Growth and development of organisms
  • LS1.C: Organization for matter and energy flow in organisms
  • LS2.A: Interdependent relationships in ecosystems
  • LS2.B: Cycle of matter and energy transfer in ecosystems
  • LS2.C: Ecosystem dynamics, functioning, and resilience
  • LS4.B: Natural selection
  • LS4.C: Adaptation
  • LS4.D: Biodiversity and humans
  • ESS3.C: Human impacts on Earth systems
  • ETS1.A: Defining and delimiting engineering problems
  • ETS1.B: Developing possible solutions
  • PS3.D: Energy in chemical processes and everyday life

Science and Engineering Practices

  • Analyzing and interpreting data
  • Asking questions and defining problems
  • Engaging in argument from evidence
  • Developing and using models
  • Planning and carrying out investigations
  • Constructing explanations and designing solutions
  • Obtaining, evaluating, and communicating information
  • Using mathematics and computational thinking

Crosscutting Concepts

  • Cause and effect
  • Energy and matter
  • Patterns
  • Stability and change
  • Systems and system models
  • Scale, proportion, and quantity
  • Influence of science, engineering, and technology on society and the natural world

Common Core
English Language Arts
  • SL.6-8.1
  • SL.6-8.4
  • SL.6-8.5
  • RST.6-8.1
  • RST.6-8.2
  • RST.6-8.3
  • RST.6-8.4
  • RST.6-8.6
  • RST.6-8.7
  • RST.6-8.8
  • RST.6-8.10
  • WHST.6-8.1
  • WHST.6-8.4
  • WHST.6-8.7
  • WHST.6-8.8
  • WHST.6-8.9


  • MP2
  • MP4
  • MP5
  • MP6

Lesson Summaries
Lesson 1: Pre-Assessment

Students generate KWL charts on different topics related to ecosystems and their interactions. Students will refer to these KWL charts at the end of each lesson to determine the progress they have made. Next, students create a model of a pond ecosystem that will be used throughout the unit. Before adding organisms to their pond, students prepare, examine, draw, and identify all the pond-water organisms using either a microscope or a hand lens. Students then begin to explore the importance of water quality as they take different measurements of their pond. To end the lesson, students create concept maps about the interactions of a particular organism within its ecosystem.
Lesson 2: Ecosystem Organization
Students discover how ecosystems are organized. Students begin by exploring the term "habitat" and how an organism's habitat must meet its needs. They develop a model of a human's habitat, their own, based on what they consider to be their basic needs. Students continue to explore ecosystem organization by conducting unbiased research on one organism's relationship with its ecosystem. After analyzing and interpreting their research, students communicate their findings in the form of a poster. Students are then exposed to the science and engineering practice of asking questions and defining problems. Students determine an engineering problem and the criteria and constraints involved in placing a new organism in a zoo exhibit. After their research, and after considering the needs of both the business and the organism, students determine the solution to their engineering problem. Then, students reexamine their pond, identify the biotic and abiotic factors within it, and determine if their pond is an ecosystem, habitat, or both. They continue monitoring water quality. At the end of the lesson, students revisit and update their KWL charts.
Lesson 3: Resources
Students explore the ideas that every organism needs resources, which they get from their ecosystems, and that each ecosystem has limited resources. Students experience cause-and-effect relationships as they explore the relationship between resources and population levels. Students begin exploring this relationship with a short activity that models how a limited number of organisms can exist in a given ecosystem due to the limited availability of resources. Students then design an investigation to explore how resource availability can affect plant growth. Students continue to explore resource availability but begin to apply it to carrying capacity. Students begin to understand that different ecosystems can have different carrying capacities based on the amount of resources available in each. Finally, students monitor changes in their pond ecosystem and consider how resource availability varies for the different organisms that live in it.
Lesson 4: Matter Cycles
Students explore how matter moves through the environment and the ways that this movement impacts all living things. They explore the movement of water, carbon, and nitrogen through the ecosystem. By the end of the lesson, students will have strengthened their foundation of knowledge for explaining how matter moves through the living and nonliving environments. Students work in groups to create a model that demonstrates the movement of water on Earth. Students then use microorganisms, algae and yeast, to explore the processes of photosynthesis and cellular respiration and their relationship to the movement of carbon. Students investigate the movement of nitrogen through the ecosystem as they play the role of a nitrogen molecule that is constantly moving between the living and nonliving parts of the ecosystem. Students end the lesson by revisiting their pond model to make observations, test water quality, and consider how matter moves within it.
Lesson 5: Energy Flow
Lesson 5 focuses on energy flow through an ecosystem using food chains and food webs. Students become familiar with the patterns among feeding relationships and begin to develop an understanding of energy flow in an ecosystem. Students also observe patterns in energy transfer between trophic levels in an ecosystem. To begin the lesson, students examine images of living things and predict how they get energy. Then, students explore feeding relationships within the African savanna. After analyzing and interpreting this information, they create a model to display the energy flow for that ecosystem. Students then explore the transfer of energy between trophic levels and observe patterns between the different levels. Finally, students monitor changes in their pond ecosystem and consider how energy is transferred between the different organisms that live in it.
Lesson 6: Organism Interactions
Students investigate the interactions that exist between many different organisms. They begin by pairing different organisms based on described interactions. Next, students look for patterns that exist among the organism pairs, and they classify them according to their interaction. By the end of the investigation, students will have a strong foundational understanding of different types of symbiosis, predation, herbivory, and competition. Students further explore interactions within an ecosystem by using a model to explore how population levels rise and fall due to predation. Then, students plan and create a model that displays competition among living things. To end the lesson, students revisit their pond models to find and observe interactions among the organisms living there.
Lesson 7: Population Changes
students explore biotic and abiotic factors that can lead to population changes. Students begin investigating population changes by creating sample ponds from their initial ponds. Students plan and carry out an investigation to change one biotic or abiotic factor in a sample pond made from their initial pond, and they observe the impact of that change on the populations living within it. Students further explore population changes that occurred due to the process of primary succession after the eruption of Mount St. Helens. Then, students use results from a quadrat sample to analyze how an invasive species impacts native populations. They further explore the effects of introduced species by looking for patterns in the characteristics of introduced organisms. Finally, students reexamine and analyze their sample pond and consider what changes have affected population size. Throughout the unit, students are asked to use evidence as they make claims about the changes in ecosystems and populations they observe.
Lesson 8: Natural Selection
Students discover that natural selection is fueled by variation in populations. Students begin exploring the phenomenon of natural selection by observing different populations of organisms and looking for variation among the individuals. Students then develop physical models to investigate how variation in feeding strategies and coloration can lead to a better chance for survival over many generations. Students continue to explore natural selection through a digital simulation, which allows them to change selection pressures to determine which traits are more successful in different scenarios. Student reexamine their ponds and consider how natural selection could occur in their ponds. Throughout the lesson, students are asked to use computational thinking and should note patterns of change in populations throughout the investigations.
Lesson 9: Biodiversity
Students explore the phenomenon of biodiversity. Students begin the lesson by considering the importance of biodiversity in an ecosystem. They then investigate four different methods ecologists use to measure biodiversity. Based on their experiences with these techniques, they discuss when it is appropriate to use each method. Then, students pair up and conduct research on whether the reintroduction of a specific organism to part of its historic range would be beneficial for both the organism and the ecosystem. Students use their research to create a poster to display their evidence-based argument and present it to the class. To end the lesson, students observe and measure their model pond ecosystem and consider the biodiversity contained within it.
Lesson 10: Human Impact
Students explore how humans impact ecosystems, how we can monitor this impact, and how we can minimize it. They design and conduct an experiment to explore how human activities impact plant growth. Students also research the impact of a particular human activity, design a plan for monitoring the impacts of their human activity, and present their plan to their classmates. Students also assess their model pond and consider how they would monitor human impact in a natural pond. Students connect human impact to the relationship between cause and effect as they explore the effects people have on ecosystems and determine different methods of monitoring those effects throughout their investigations.
Lesson 11: Assessment
This assessment has two parts: a performance assessment and a written assessment. In the performance assessment, students apply the knowledge and skills they have acquired during the unit to research an ecosystem service and threats to that service. Then, students research existing solutions to one of the threats to their ecosystem service and design their own solution to lessen or eliminate that threat. Students then present their solution to the class. In the written assessment, students respond to multiple-choice and constructed-response items aligned to concepts covered in this unit.

*Next Generation Science Standards® is a registered trademark of WestEd. Neither WestEd nor the lead states and partners that developed the Next Generation Science Standards were involved in the production of this product, and do not endorse it.


Shipping Information or Purchase Restrictions
  • USDA or USDOT regulations restrict this item from shipping to these locations: Alaska, Virginia. Dwarf aquarium frogs cannot be shipped into some states. Restricted states will receive guppies.
What’s Included:
  • 1 Living Materials Voucher Set, Ecosystems and Their Interactions 1-Class
  • 16 Ecosystems and Their Interactions Student Guide
  • Ecosystems and Their Interactions Teacher Edition
  • 1 Unit Technology Pack (includes digital access to the Teacher Edition and digital student access to the Student Guide)
  • 6 Aqua-Terrarium, Plastic, Large
  • 8 Aquarium Dip Net
  • 10 Aquarium, Plastic, 1/2 gal
  • 200 Bead, Styrene, Yellow, 8 mm
  • 4 Black Beans, 1 lb
  • 16 Bookend, Small, Nonslip Base
  • 1 Card Set, Nitrogen Movement, Pack of 4 Sets
  • 1 Card Set, Organism Interactions, Pack of 16
  • 8 Chopstick
  • 8 Clamp Lamp, with Reflector (without bulb)
  • 18 Clothespin, Wood
  • 45 Container, Plastic, 16 oz
  • 4 Container, Rectangular, Plastic, 48 oz
  • 10 Cup, Plastic, 1 oz
  • 250 Cup, Plastic, 4 oz
  • 50 Cup, Plastic, 7 oz
  • 8 Forceps, Plastic
  • 20 Fork, Plastic
  • 1 Whisper® Air Pump 20 UL
  • 16 Lens, Hand
  • 4 Lid, Planter Tray
  • 1 Mat Set, Ecosystem, 1–5, Pack of 8 Sets
  • 8 Mat, Algae and Protists
  • 8 Mat, Biodiversity
  • 8 Mat, Macroorganisms
  • 8 Mat, Natural Selection Habitat
  • 72 Microscope Slides, Student-Grade, Standard
  • 10 Petri Dish, with Lid
  • 1 Photo Card Set, Barn Owl, Pack of 4
  • 1 Photo Card Set, Introduced and Invasive Species, Pack of 8
  • 1 Photo Card Set, Koala, Pack of 16
  • 1 Photo Card Set, Mouse, Pack of 16
  • 1 Photo Card Set, Organism
  • 1 Photo Card Set, Resource, Pack of 5
  • 1,200 Pom-Pom, Blue, 1/4"
  • 1,200 Pom-Pom, Red, 1/4"
  • 1,200 Pom-Pom, White, 1/4"
  • 1,200 Pom-Pom, Yellow, 1/4"
  • 16 Pom-Pom, Yellow, 2"
  • 1 Ruler, Transparent
  • 1 Sign Set, Nitrogen Cycle
  • 16 Teaspoon, Plastic
  • 75 Tube, Plastic, 2.5 x 15 cm
  • 1 Water Quality Test Kit, Ecosystems and Their Interactions 1-Class
  • 1 Air Line Tubing, 8 ft
  • 2 Air Releaser, Stone
  • 1 Aluminum Foil, 25-ft Roll
  • 1 Calcium Chloride, Anhydrous, 50 g
  • 600 Coverslip, Plastic
  • 250 Culture Tube, Disposable
  • 16 Fabric Square, Mesh, 6"
  • 1 Fertilizer, All-Purpose, Water Soluble, 20-20-20, 8 oz
  • 1 Frog Bites, 1.2 oz
  • 2 Gravel, Aquarium, 5-lb Bag
  • 9 Hydrogen Carbonate Indicator, 30 mL
  • 200 Microchemistry Pipet, Jumbo, Capacity 7.0 mL
  • 16 Paper, Card Stock, White, 12 x 18"
  • 1 Parafilm®, 10-ft Roll
  • 1 Rice, White, Quick-Cooking, 7-oz Box
  • 2 Seed, Radish, var. "Scarlet Globe," 1 oz
  • 1 Seed, Sunflower, 16 oz
  • 3 Sodium Alginate, Powder (for 3% solution)
  • 2 Soil, Potting, with Seed Starter, 16-qt Bag
  • 4 Solution, Protoslo® Quieting, Lab Grade, 15 mL
  • 20 Syringe, 10 mL
  • 1 Toothpick, Flat, Box
  • 1 Transparency Quadrat Sheet
  • 1 Yeast, Active Dry, 1/4-oz Pack
Needed But Not Included:
  • 16 Microscopes (we recommend item #591182)
Return Policy:

If for any reason you are not satisfied with this item, it is eligible for a return, exchange, refund, or credit up to 180 days from date of purchase. Restrictions may apply. Returns & Exchanges Policy.