Extensions
Examining Pond Water
Have students bring in pond water and observe a drop
with a microscope. Have them draw any microorganisms
they see. Encourage them to determine whether each type
of organism moves with cilia, flagella, or pseudopods.
Research
Have students do library or Internet research to find out
how protists are important to humans. (They should learn
that 70% of Earth’s oxygen is produced in the ocean by
protists, they are food for most ocean organisms, some
cause diseases such as malaria, and they are used to make
products ranging from toothpaste to fertilizers.
Modeling an Amoeba
10 minutes
Teacher
Demonstration
Objectives
• Students identify organelles in a model of an amoeba.
• Students infer how an amoeba uses its pseudopods by observing
a model.
Materials
For the teacher
1
Inquiry Focus
• Use Models
*amoeba model (see In
Advance below)
*Not provided in kit
In Advance
Make a model of an amoeba as follows: Put the kit’s rubber ball and
48 marbles into the translucent latex glove. Fill the glove with water,
and close it tightly with a rubber band.
A Model amoeba
8 • EXPERIENCE SCIENCE
A Live amoeba
1. Present the model.
Show students the prepared glove and explain that it
is a model of an amoeba. Ask: What represents the
cell membrane? (the glove) What represents the
cytoplasm? (water) What represents the nucleus?
(the ball) What represents the organelles? (the
marbles)
Modeling an Amoeba (continued)
2. Discuss amoeba structures.
Point out that an amoeba has no eyes, legs, or mouth.
It moves through water until it bumps into something
to eat. Ask if students observed organelles flowing in
the cytoplasm when they examined the amoeba with a
microscope. Remind students that many life processes
take place in the organelles. For example, the nucleus is
the control center of the cell. It is involved in reproduction and directs all the activities of the cell.
3. Demonstrate an amoeba’s movement.
Explain that the cytoplasm flows in one direction,
stretching the cell membrane and extending the body
into a pseudopod. Use the model to demonstrate this.
Place the model in your hand with the glove fingers
hidden underneath in your palm. Let one glove finger
at a time pop out to represent a pseudopod.
Teaching Tip
Step 3: Practice this demonstration before doing it with the
class. When you are not using
the amoeba model, store it in an
empty bowl or container, as water
tends to seep out through the
latex over time.
Assessment
Ask: How does an amoeba capture its food?
(The amoeba moves through water until it bumps into a
food organism. It surrounds the food with its pseudopods.
The food is taken into the food vacuole.)
Homework
Name
Date
Creating a Microorganism
STUDENT RESOURCE 1.10
HOMEWORK SHEET
Creating a Microorganism
Student Resource
• 1.10 Creating a Microorganism
Create a new microorganism. Think about where your
microorganism lives, how it moves, and what it eats. Use
materials you find at home to build your microorganism. Then
draw it in the box below. Label its parts. If the microorganism is
only one cell, label the nucleus and food vacuole.
1. Make copies of Student Resource 1.10, Creating a
Microorganism, and distribute to students.
Tell how your microorganism eats and moves.
Descriptions will vary.
Copyright © Houghton Mifflin Company. All Rights Reserved.
Students’ creations will vary.
2. Have students create a microorganism at home.
Encourage them to be creative and to use whatever
materials they want, such as toys and food items, so
long as the materials are safe. Emphasize that their
organisms must be scientifically realistic in terms of
structures and behavior.
3. Give students an opportunity to show and describe
their creations to the rest of the class.
20 • CLASSIFICATION • SECTION 1 MICROORGANISMS
Student Resource 1.10 (p. 20)
SECTION 1 MICROORGANISMS • 9
Section Assessment
Name
Date
STUDENT RESOURCE 1.11
ASSESSMENT SHEET
Section 1 Assessment
Vocabulary
1 How are algae and protozoans alike? How are they different?
Both algae and protozoans are protists. Algae are
producers that contain chlorophyll and make their own
food. Protozoans are consumers and must eat food.
2 This line is 6 mm long.
How long is the line in micrometers?
6,000
1
*microscope
1
*teacher-prepared depression
slide of microorganism,
from Investigate 1 (see Note
below)
Student Resource
• 1.11 Section 1 Assessment
µm
Note: You may want to use a different microorganism at each
station, or you could prepare additional slides and use the same
microorganism at all stations.
How Microorganisms Move
3 How does this microorganism move?
Copyright © Houghton Mifflin Company. All Rights Reserved.
Materials
For each station
It whips its flagellum around like a helicopter propeller.
Identifying Microorganisms
4 Examine the slide at a microscope that your teacher has set
up. Find a microorganism on the slide. Write the name of
the organism and tell whether it is a protozoan, an alga, or
a many-celled animal.
Answer will depend on the microorganism used.
CLASSIFICATION • SECTION 1 MICROORGANISMS • 21
Student Resource 1.11 (p. 21)
1. Set up enough stations around the room to allow onethird of the class to work alone at a station during the
hands-on portion of the assessment.
2. Make copies of Student Resource 1.11, Section 1
Assessment, and distribute to students.
3. Divide the class into three groups. While one group is
working at the stations to complete the hands-on portion of the assessment, the other two groups can be
completing the top part of the assessment. Rotate the
groups through the stations until each has completed
the hands-on portion of the assessment.
4.Discuss the answers as a whole-class activity.
10 • EXPERIENCE SCIENCE