Unit Overview

In Mosa Mack’s Interactions of Organisms Unit, students are led through a progression of three inquiry lessons that focus on three different types of interactions of organisms, including mutualism, predation, and competition.

  • Lesson 1
    Lesson 1: Solve: Sea Urchin Invasion + Clownfish Mystery

    Solve: Sea Urchin Invasion + Clownfish Mystery

    Choose to solve a live video mystery exploring the invasion of purple sea urchins in Pacific kelp forests, or solve an animated mystery to discover how organism interactions are to blame for the death of a clownfish in a coral reef ecosystem. By the end of the The Solve, students discover a variety of relationships that exist among organisms in an ecosystem, including competition, predation, and mutualism. (Live Solve: 100 minutes; Animated Solve: 45-75 minutes).

  • Lesson 2
    Lesson 2: Make: Use Multimedia Clues to Determine Organisms’ Interactions

    Make: Use Multimedia Clues to Determine Organisms’ Interactions

    Students will travel to three stations that represent three ecosystems. After examining the three types of interactions, including mutualism, predation, and competition, at each station, students will demonstrate their understanding through a creative presentation. (150-160 mins)

  • Lesson 3
    Lesson 3: Engineer: Engineer a Solution for an Invasive Species

    Engineer: Engineer a Solution for an Invasive Species

    Students develop and design a solution to control an issue created by an invasive species. Students will draw a technical sketch or build a model of their solution. (200 mins)

  • Next Generation Science Standards
    Analyze and interpret data to provide evidence for the effects of resource availability on organisms and populations of organisms in an ecosystem. [Clarification Statement: Emphasis is on cause and effect relationships between resources and growth of individual organisms and the numbers of organisms in ecosystems during periods of abundant and scarce resources.]
    Construct an explanation that predicts patterns of interactions among organisms across multiple ecosystems. [Clarification Statement: Emphasis is on predicting consistent patterns of interactions in different ecosystems in terms of the relationships among and between organisms and abiotic components of ecosystems. Examples of types of interactions could include competitive, predatory, and mutually beneficial.]
  • 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
    • Students may initially think that the interactions in ecosystems only involve animals. Emphasize to students that plants also play important roles in interactions within ecosystems.
    • Students tend to limit their thinking of interactions in an ecosystem to biotic (living) components (example: animals interacting with other animals or plants). Emphasize to students that organisms interact with the abiotic (non-living) portions of the environment just as much as the biotic components. Abiotic components include water, temperature, amount of sunlight, and type of soil, and these can have major impacts on the health of the ecosystem.
    • Students tend to think that competition in an ecosystem is limited only to organisms of the same species competing for resources (example: two species of shark competing for same food source). Emphasize that competition can exist between different species of organisms competing for resources other than food as in the case of the American kestrel (falcon) and gray squirrel competing for nesting sites within the ecosystem.
    • Students tend to think that food is the only resource that animals compete for within an ecosystem. Emphasize to students that animals can compete for food, water, and shelter within an ecosystem.
    • Students may think that predation is a negative interaction in an ecosystem. Encourage students to think about how predator-prey relationships keep an ecosystem balanced.
    • Students tend to think that predator and prey populations are similar in size.Emphasize to students that prey populations tend to be larger in size due to faster reproductive rates and larger number of offspring/breeding cycles as compared to predator populations.
  • Vocabulary
      • Ecosystem
      • Predation
      • Mutualism
      • Competition
      • Abiotic
      • Biotic
  • Content Expert
    • Anjelica Gonzalez, PhD
      Donna L. Dubinsky Associate Professor Biomedical Engineering Yale University
  • 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.

    • 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.

    • 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.

    • Life is a Competition

      Life is not easy, and often organisms must compete with organisms who are better suited than themselves for resources. One of the people who helped us to realize this and is tied to the theory of evolution was Thomas Malthus in his book "An Essay on the Principle of Population."