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Classroom Resources | Activities for Episode
Two 
Episode One: The Tree of Life
Activity 2: Life Everywhere!
Grades K-5
Objectives:
- Students will explore the basic requirements for life to exist.
- Students will understand the role of microbes in the "Tree of Life."
- Students will conduct a simple experiment to show the prevalence and
variety of microbes in their world.
Ties to Broadcast and Web Sites:
- Intimate Strangers: The Tree of Life
Excerpt from "The Quest"
- The Wonders
of Microbes
Basic information about microbes: a microbe portrait gallery, information
about various types of microbes, and what microbes do
- Microbe Zoo
Great Web site for elementary students to learn about microbes in their
lives: Dirtland, Animal Pavilion, Snack Bar, Water World, and Space
Adventure. Includes Microbe of the Month portrait gallery.
Procedure for Classroom Activity:
- In order to motivate student interest and begin their understanding
about the concept of "life," arrange several animate and inanimate objects
(for example, a rock, flower, piece of bread, bowl of water, toy, pencil,
animal, picture of a human) on a table and ask students to tell you
which they think are "alive" and why. List on the board. Then ask students
why they think the objects they chose are alive. Develop this conversation
and make a list of "what makes something 'living.'" (For example, living
things all obtain food, metabolize, reproduce, and react to their surroundings.)
- Draw a sketch of the "Tree of Life" showing the main branches: monera
(bacteria, blue-green algae), protista (algae and protozoa), fungi (mushrooms
and molds), plants (mosses, ferns, seed/flowering plants), and animals.
Explain that students will be learning about microbes, the smallest
living things that exist on the "Tree of Life."
- Show "The Quest" from the program, Intimate
Strangers: The Tree of Life. Discuss the ongoing search to
better understand the tree of life, the role of DNA, and microbes' ability
to live in a hot volcano, on human skin, and everywhere in the world-even
in the students' school. Use the web resources listed above to show
students pictures of microbes and to help them learn more about microbes
by visiting "The Microbe Zoo."
- With the students, design a simple experiment to see where microbes
might be found in the school environment. Use the following basic steps
of scientific procedure:
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Frame the Investigation:
A. Develop a hypothesis or question to answer. A sample question
might be "Where can microbes be found?"
Design the Investigation:
B. Ask students to recommend locations in the classroom or
around the school to test for the presence of microbes. (Locations
to test might include: cafeteria countertop, classroom floor,
doormat, water faucet, pet area, toilet seat, drinking fountain,
soil on playground, teacher's coffee cup, water puddle, door
knob, desktop, etc.)
C. Prepare a culture medium to grow microbes on. This might
be sterile agar or something as homespun as tomato soup or apple
cider. Place in clean muffin cups, baby food jars, or in sterile
petri plates, if available.
D. Using a consistent method, swab each of the test locations
with a clean cotton swab and streak gently over the medium in
one of the test containers. Label each container with the name
of the test location. Do not use one container, so that the
test cultures can be compared to it.
E. Cover the containers with plastic wrap and place in a warm
environment.
Collect Data:
F. Observe and record the changes each day for two weeks. Make
drawings of the changes and, if possible, use a microscope to
try to identify the microbes found.
Analyze the Results:
G. Draw conclusions about where microbes grow at school and
why certain microbes grow better in certain conditions.
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- Ask students to research the Web sites listed above and other resources
and write reports about different kinds of microbes to share with each
other. Discuss the ways microbes can help and harm us. Why is it important
to know about microbes?
Classroom Resources | Activities for Episode
Two
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