Unit Overview

Students discover organisms interconnect through feeding relationships where energy flows from producers through consumers to decomposers. Through solving disappearing prey mysteries or investigating ecosystem crashes, designing visual food webs with organism cards showing energy flow arrows from food sources to consumers, and engineering cafeteria waste reduction systems using decomposer knowledge creating composting solutions, students learn removing one species disrupts entire ecosystem networks.

  • Lesson 1
    Lesson 1: Solve: Hungry Frog Mystery + Vocabulary Mind Map

    Solve: Hungry Frog Mystery + Vocabulary Mind Map

    Frank the bullfrog lives near a temperate forest and loves chomping on crickets and worms—but they've all vanished! Students follow Mosa as she interviews a singing cricket and a defiant earthworm, discovering that changes in one part of an ecosystem ripple through the entire food web. If plants die, herbivores starve, then carnivores that eat herbivores disappear too. By the end, students understand interdependence: organisms in ecosystems rely on complex feeding relationships where removing one link affects everything connected to it.

  • Lesson 2
    Lesson 2: Make: Design a Food Web to Show Feeding Relationships

    Make: Design a Food Web to Show Feeding Relationships

    Design a visual food web showing feeding relationships in an ecosystem. Students receive organism cards (producers like plants and algae, consumers at different levels, decomposers like fungi and bacteria) and a web background. They arrange organisms, draw arrows showing energy flow direction (from food source → to eater), and color-code different trophic levels. Key insight: arrows point from what's being eaten to what's eating it (grass → grasshopper → frog → hawk). The completed web reveals how multiple food chains interconnect, creating complex ecosystem networks where energy flows from sun → producers → consumers → decomposers.

  • Lesson 3
    Lesson 3: Engineer: Engineer a Solution to a Food Waste Problem

    Engineer: Engineer a Solution to a Food Waste Problem

    Use food web knowledge to reduce cafeteria waste sent to landfills. Students observe their school cafeteria, identify types of waste (uneaten food, packaging, organic scraps), research how decomposers break down organic matter and return nutrients to ecosystems, then engineer solutions: maybe composting bins with specific decomposer organisms, worm farms processing food scraps, anaerobic digesters, or vermicomposting systems. They build models, test decomposition rates with different materials, and present proposals showing how their designs mimic natural decomposition cycles to reduce waste.

  • Next Generation Science Standards
    5-LS1-1
    Support an argument that plants get the materials they need for growth chiefly from air and water. [Clarification Statement: Emphasis is on the idea that plant matter comes mostly from air and water, not from the soil.]
    5-LS2-1
    Develop a model to describe the movement of matter among plants, animals, decomposers, and the environment. [Clarification Statement: Emphasis is on the idea that matter that is not food (air, water, decomposed materials in soil) is changed by plants into matter that is food. Examples of systems could include organisms, ecosystems, and the Earth.] [Assessment Boundary: Assessment does not include molecular explanations.]
    5-PS3-1
    Use models to describe that energy in animals’ food (used for body repair, growth, and motion and to maintain body warmth) was once energy from the sun. [Clarification Statement: Examples of models could include diagrams, and flow charts.]
  • Inquiry Scale
    • Each lesson in the unit has an Inquiry Scale that provides directions on how to implement the lesson at the level that works best for you and your students.
    • “Level 1” is the most teacher-driven, and recommended for students in 4th-5th grades. “Level 4” is the most student-driven, and recommended for students in 7th-8th grades.
    • For differentiation within the same grade or class, use different inquiry levels for different groups of students who may require additional support or an extra challenge.
  • Common Misconceptions
    • Arrows in a food web show the direction of energy flow, not which predators eat which prey. Directionality of arrows matters.
    • Not all of the energy in one organism gets passed to the next level of organism. 90% gets released as heat.
    • Not all organisms need to eat others to get energy. Producers produce their own energy from the sun.
  • Vocabulary
      • Ecosystem
      • Predator
      • Producer
      • Primary Consumer
      • Decomposer
      • Secondary Consumer
  • Content Expert
    • Clive G. Jones
      Terrestrial Ecologist, Cary Institute of Ecosystem Studies Expertise: Biodiversity, Environmental Management Modeling and Assimilation Office
  • Leveled Reading

    * To give our users the most comprehensive science resource, Mosa Mack is piloting a partnership with RocketLit, a provider of leveled science articles.

    • Webs Are Not Only For Spiders

      Food webs are much more complicated than a simple food chain, and they show the way that energy is exchanged by organisms. Since there are so many different thing connected in ecosystems, balance of each resource is very important and difficult to maintain.

    • What's For Dinner?

      In the energy pyramid and food web, there are specific roles that different organisms play. Some put energy into the system, others eat each other for energy, and some breakdown dead things to recycle them back into the environment.

    • Nitrogen Cycle

      In this article, students read about the different parts of the nitrogen cycle. We breathe in nitrogen with every breath, but we can't use any of it. Without bacteria and plants making nitrogen available, living things wouldn't even have the things they need to build DNA!

    • What's Your Job?

      Different organisms have different jobs in an ecosystem, but sometimes they step on each other's toes. This article explains how organisms compete with each other for living space, the roles that they have and the niches that they fit into within their environment.

    • Can't We All Just Get Along?

      In cartoons, we might see different organisms being either friends or enemies, but in nature it's much more complicated. Symbiotic relationships change the way both organisms live, and some can be mutualistic (good for both). Some relationships are parasitic (take, hurt, take) and others are more commensal which help one organism involved and don't hurt the other.

    • The Sun Powers It All

      Introducing the unit, this article builds up that in order for everything to have the energy it needs to live, we need the sun and the organisms that make food from its energy. These organisms store the energy they make and are used by other living things to get the energy they need.

    • Energy Pyramid

      Energy for life starts out with producers, those organisms that can make their own food. From there, energy is lost to the environment as each different living thing is consumed by another. We can use a pyramid to envision the spread of life at each level and how energy is passed up to higher level organisms.

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