Lesson Plan

Characteristics of Multicellular Organisms

Objectives

In this lesson, students use microscopes to examine organisms in a sample of pond water. They also classify groups of vertebrates and invertebrates. Students will:

  • identify examples of multicellular organisms.
  • describe a multicellular organism as a system that is composed of parts that work together for survival.
  • use observations to infer how multicellular organisms meet their needs for survival.

Essential Questions

Vocabulary

  • Characteristic: Feature or trait indicating the typical or distinguishing attributes and qualities of a person, group, action, or thing.
  • Multicellular Organism: Organism consisting of more than one cell.
  • Organism: Any living thing.
  • Specialization: The ability of cells in multicellular organisms to perform specific functions.
  • Unicellular Organism: Organism consisting of only one cell.

Duration

90 minutes/2 class periods

Prerequisite Skills

Prerequisite Skills haven't been entered into the lesson plan.

Materials

  • Pond Water Activity, Option A:

o   pond water

o   plastic cups

o   microscopes

o   microscope slides

o   eyedroppers

o   copies of Guide to Pond Water Organisms (S-6-3-2_Guide to Pond Water Organisms.docx)

o   copies of Pond Water Lab Activity worksheet (S-6-3-2_Pond Water Lab Activity and KEY.docx)

  • Pond Water Activity, Option B:

o   computers with Internet access for a Virtual Pond Dip

www.microscopy-uk.org.uk/index.html?http://www.microscopy-uk.org.uk/ponddip/index.html

o   copies of Virtual Pond Water Lab Activity worksheet (S-6-3-2_Virtual Pond Water Lab Activity and KEY.docx)

Related Unit and Lesson Plans

Related Materials & Resources

The possible inclusion of commercial websites below is not an implied endorsement of their products, which are not free, and are not required for this lesson plan.

  • Pond Water Activity, Option A:

o   pond water

o   plastic cups

o   microscopes

o   microscope slides

o   eyedroppers

o   copies of Guide to Pond Water Organisms (S-6-3-2_Guide to Pond Water Organisms.docx)

o   copies of Pond Water Lab Activity worksheet (S-6-3-2_Pond Water Lab Activity and KEY.docx)

  • Pond Water Activity, Option B:

o   computers with Internet access for a Virtual Pond Dip

www.microscopy-uk.org.uk/index.html?http://www.microscopy-uk.org.uk/ponddip/index.html

o   copies of Virtual Pond Water Lab Activity worksheet (S-6-3-2_Virtual Pond Water Lab Activity and KEY.docx)

Formative Assessment

  • View
    • Pre-assess students’ understanding of the difference between unicellular and multicellular organisms during the discussion at the beginning of the lesson.
    • Collect and check the Virtual Pond Water Lab Activity worksheet for individual assessment.
    • Circulate around the classroom during the lab and assess students’ understanding of how to classify multicellular organisms.
    • Collect and check the exit slips.

Suggested Instructional Supports

  • View
    Active Engagement, Modeling, Explicit Instruction
    W: Students learn to differentiate between the characteristics of unicellular and multicellular organisms through direct observation using a microscope.
    H: Student interest is hooked in a discussion of what their own bodies are made of, and a discussion that accesses prior knowledge of unicellular and multicellular organisms.
    E: The hands-on lab activity makes students’ understanding of multicellular organisms’ characteristics real.
    R: Students reflect on their direct observations using the microscope by completing a lab worksheet.
    E: Students express their understanding by completing a lab activity worksheet.
    T: This lesson is tailored by providing additional assistance during the lab activity. See the Extensions section for specific modifications.
    O: The lesson begins with a discussion of the difference between unicellular and multicellular organisms. Then students complete a guided lab inquiry into the characteristics of multicellular organisms.

Instructional Procedures

  • View

    To prepare, look at Options A and B for this lesson and decide which one to utilize. If you use Option A, order pond water from a biological supply company or collect a pond water sample (see Related Resources for tips on collecting pond water). You can save time by setting up microscope lab stations before class with a microscope, slide, eyedropper, and container of pond water. If you use Option B, explore the Virtual Pond Dip Web site before conducting the activity.

    Introduce the lesson by asking students what their bodies are made up of. (Possible answers include cells, molecules, bones, muscles, organs, and organ systems.) Tell them that the cell is the basic unit of life and some organisms have only one cell. Define unicellular and multicellular.

    Ask students, “Why do you think our bodies are made up of many tiny cells instead of just one big cell?” (Elicit that cells can perform different kinds of functions in the body.) Explain that multicellular organisms are able to do many things because they have specialized cells that perform many different functions. Just like different people perform different kinds of jobs, such as being a doctor or a teacher, different cells can do different jobs too (e.g., muscle cells for movement and brain cells for thinking). Add that each cell must be small enough to transport substances in and out quickly enough to support life functions.

    Make a T-chart on the board with the headings “Unicellular” and “Multicellular.” Have students work in pairs for a few minutes to brainstorm a list of organisms for each, and then select a few pairs to share with the class. Possible answers include:

    Unicellular

    Multicellular

    Amoebas

    Humans

    Bacteria

    Trees

    Euglena

    Dogs

    Yeast

    Fish

    Paramecium

    Birds

    Guide the class in generating a list of things that both unicellular and multicellular organisms need to survive. Write the list on the board. The list should include food, water, oxygen, and shelter.

    Note: Discuss shelter in terms of the appropriate environmental conditions in which an organism can survive, including protection from predators and the weather, temperature, pressure, altitude, and salinity.

    Pond Water Organisms Lab Activity

    Option A: Observing Pond Water Organisms Under the Microscope

    Review proper microscope use and lab safety with students.

    Demonstrate how to prepare a slide by using the eyedropper to place a few drops of water on the middle of the slide. Also demonstrate how to begin with the lowest magnification on the microscope.

    Divide students into small groups and have each group sit at a microscope station. Hand out the Guide to Pond Water Organisms (S-6-3-2_Guide to Pond Water Organisms.docx) and the Pond Water Lab Activity worksheet (S-6-3-2_Pond Water Lab Activity and KEY.docx). Explain that the guide does not include all of the possible organisms in the pond water sample, just the most common ones.

    Have students complete the lab activity, following the directions on the worksheet. During the lab, circulate around the room to assist with microscope use and answer questions. If students see organisms that are not on the guide handout, you may have them use a field guide book or a Web site such as Pond Water Critters That You Can See with a Microscope: Protozoans and Small Animals or Pond Life Identification Kit (see Related Resources). Have students clean up all materials when done.

    Call on two or three volunteers to draw on the board an organism they saw during the lab. Have the class use the guide to try to identify the organisms. Ask how each of the organisms might get the food and oxygen it needs. Explain that a unicellular organism has to do these jobs with its one cell, but multicellular organisms have many cells to do different jobs like moving, digesting food, and getting rid of wastes.

    Option B: Observing Pond Water Organisms in a Virtual Lab Activity

    Hand out copies of the Virtual Pond Water Lab Activity worksheet (S-6-3-2_Virtual Pond Water Lab Activity and KEY.docx). Have students read the directions and answer any questions they may have.

    Divide students into small groups and have each group sit at a computer station. Have groups complete the virtual lab activity, following the directions on the worksheet. During the lab, circulate around the room to assist with computer use and answer questions.

    Call on two or three volunteers to draw on the board an organism they saw during the lab. Have the class use the guide to try to identify the organisms. Ask how each of the organisms might get the food and oxygen it needs. Explain that a unicellular organism has to do these jobs with its one cell, but multicellular organisms have many cells to do different jobs like moving, digesting food, and getting rid of wastes.

    Have students complete an exit slip answering the question, “What is one advantage of having specialized cells in your body?”

    Extension:

    • Students who may be going beyond the standards can look up the classifications of the five organisms they observed in the laboratory and describe the characteristics of each group.
    • Students who might need an opportunity for additional learning can find five pond-water organisms. Provide a list of unicellular and multicellular organisms for them as a reference during the lab.

Related Instructional Videos

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DRAFT 05/09/2011
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