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(Sessions I and II)
BROWARD COUNTY ELEMENTARY SCIENCE BENCHMARK PLAN
Grade 2—Quarter 4
Activities 37 & 38
SC.G.1.1.2
The students knows that plants and animals are dependent upon each other for survival.
SC.G.1.1.4
The student knows that animals and plants can be associated with their environments by an
examination of their structural characteristics.
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SC.H.1.1.1
The student knows that in order to learn, it is important to observe the same things often
and compare them.
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SC.H.1.1.3
The student knows that in doing science, it is often helpful to work with a team and to share
findings with others.
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SC.H.1.1.5
The student uses the senses, tools, and instruments to obtain information from his or her
surroundings.
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© Delta Education. Photocopying and distribution prohibited.
SC.H.3.1.1
The student knows that scientists and technologists use a variety of tools (e.g.,
thermometers, magnifiers, rulers, and scales) to obtain information in more detail and to
make work easier.
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ACTIVITY ASSESSMENT OPPORTUNITIES
The following suggestions are intended to help identify major concepts covered in the activity
that may need extra reinforcement. The goal is to provide opportunities to assess student
progress without creating the need for a separate, formal assessment session (or activity) for
each of the 40 hands-on activities at this grade level.
1. Session I—Activity 37: Have students compare the two illustrations of the aphid and
ladybug side-by-side. Then ask, What part of the ladybug gives you the best clue as to
what it might feed on? (The mouth parts of the insect.) Then ask, Do you think the
ladybugs and aphids might feed on the same things based on a comparison of their
mouth parts? (No, one has a mouth that can puncture a plant stem, the other seems to
have pincers made for grabbing.)
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2. Session II—Activity 38: Draw a diagram on the board that connects the words “bean
plants” and “aphids” with a single straight line. Ask, If we were to make this line into an
arrow as part of a food chain, which way should the arrow face? (The arrow should go
from the bean plant to the aphid, showing that the bean plant is eaten by the aphid.) Then
ask, If we were to add “ladybug” to this food chain, where should you place it and
which way should the arrow face? (The ladybug would follow after the aphid, and the
arrow would go from the aphid to the ladybug. This would show that the ladybug is a
predator that eats aphids.) Finally, ask, What would happen to the ladybug if there were
no bean plants? (Without the bean plants there would be no aphids for the ladybug to
eat. They would die.)
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3. Use the Activity Sheet(s) to assess student understanding of the major concepts in the
activity.
In addition to the above assessment suggestions, the questions in bold and tasks that
students perform throughout the activity provide opportunities to identify areas that may
require additional review before proceeding further with the activity.
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activities 37 & 38 Land Predators
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37&38 Land Predators
OBJECTIVES
Students observe ladybugs and discover
that they eat aphids. Continuing their
observations over time, students track the
decrease in an aphid population after
introducing ladybugs into its habitat.
For each team of four
1
foam cup with beans and aphids
(from Activity 36)*
4
magnifiers
1
marker, felt-tip*
4
pipe cleaners
1 pair scissors*
The students
þ
þ
predict what ladybugs will eat
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discuss the interdependency of plants
and animals
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observe that the aphid population is
reduced by a predator—the ladybug
Session I—Activity 37 About 45 minutes,
about 10 days after Activity 35 began
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Session II—Activity 38 About 30 minutes, 3
days after Session I
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VOCABULARY
ladybug
predator
prey
1
1 roll
1
*provided by the teacher
PREPARATION
Session I—Activity 37
1
Make a copy of Activity Sheet 37 for each
student.
2
Arrange for the use of an overhead
projector.
3
Cut eight pieces of tape 5 cm (2 in.) long
to label the containers. Cut or tear paper
towels into quarters, enough for one piece
for each team.
4
Shortly before class, use a pipe cleaner
to put two ladybugs in each of eight
plastic containers, promptly placing a lid
on each to prevent the ladybugs’ escape.
MATERIALS
For each student
1
1 pr
1 pr
Activity Sheet 37
gloves, disposable
safety goggles*
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containers, plastic, 10-oz
ladybugs
lids, with holes, for 10-oz
containers
overhead projector*
paper towels*
tape, masking
transparency, Ladybug
water, tap*
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SCHEDULE
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For the class
examine the anatomy and observe the
behavior of ladybugs
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Session II—Activity 38
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Each student will need his or her copy of
Activity Sheet 37. Each team will need their
container of aphids and ladybugs as well as
four magnifiers.
Activity Sheet 37
Land Predators
Session I—Activity 37
1. Describe the ladybug. round and red with spots, six legs,
can crawl and fly, big eyes on side of head
2. Label the body parts of the ladybug in the drawing.
wing covers
BACKGROUND INFORMATION
wings
head
antennae
Ladybugs are a kind of beetle that eats other
small insects, such as aphids, scale insects,
and plant mites. There are more than 4,500
different species of ladybugs, with about 400
kinds found in the United States and Canada.
Most of these species are remarkably similar
in size and shape, although they differ greatly
in coloration. Some are red or yellow with
black spots; others are black with red or
yellow spots. Their coloring differs even
among members of the same species.
legs
3. Predict: What do you think the ladybug will eat?
(Circle one.) bean leaves/aphids
4. Count the populations of ladybugs and aphids in your team’s
container each day for 3 days.
Day
Date
How many aphids?
How many ladybugs?
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activities 37 & 38 Land Predators
6. What happens to a population of aphids if ladybugs are
present?
The population of aphids gets smaller.
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Animals that eat other animals are called
predators; the animals that are eaten are
called prey. Students may think of predators
as being large animals like wolves or tigers,
but they learn in this activity that even the
tiny ladybug can be an effective predator,
eating great numbers of aphids and thereby
reducing their population.
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Session II—Activity 38
5. What happened when you put ladybugs in a container with
aphids?
The ladybugs ate the aphids.
Because both ladybugs and their larvae are
such voracious eaters of many kinds of insect
pests, they are widely used as biological
control agents to reduce the populations of
aphids and other plant-eating insects.
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Guiding the Activity
Additional Information
Session I—Activity 37
1
Give each student a copy of Activity
Sheet 37. Distribute a container of ladybugs
and four magnifiers to each team of four.
Write ladybug on the board and tell students
that ladybugs are beetles that eat other small
insects. Allow students time to examine the
ladybugs and write a description of them on
their activity sheets.
Project the Ladybug transparency and point
out the various body parts of the insect. Have
students look for these body parts on their
ladybugs and label the illustration on their
activity sheets (see Figure 37-1).
Ask students, How are the ladybugs similar
to the aphids you have studied? How are
they different?
Remind them to handle the containers gently
and not to remove the lids.
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Students may say that ladybugs have six legs
and three body parts (head, thorax, and
abdomen) like the aphids. They live on land
like the aphids. They are different in color
and shape from the aphids. Unlike aphids,
they have wings.
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© Delta Education. Photocopying and distribution prohibited.
Point out that the wings of the ladybug allow
it to easily move from one plant to another.
Its legs allow it to crawl around the plants in
search of food.
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Students should look for the head, antennae,
legs, wings, and wing covers on their living
ladybugs.
wings
wing covers
head
antennae
legs
£
2
Tell students that ladybugs are often found
on the plants in gardens and ask, What do
you think they might eat?
Figure 37-1. The ladybug.
Students are likely to suggest that the
ladybugs eat either the plants or the other
insects in a garden.
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Guiding the Activity
Ask, How can we find out whether ladybugs
eat plants or insects?
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Additional Information
Lead students to conclude that one way to
find out is to place ladybugs in containers
with plants and with insects and observe
what happens.
Distribute four pipe cleaners, a pair of
scissors, a piece of masking tape, a felt-tip
marker, a piece of paper towel, and their
foam cup with bean plants and aphids to
each team of four.
Have each team write their names and
today’s date on a piece of masking tape and
label their ladybug container. Have them wet
their paper towel pieces, fold them, and place
them in the ladybug container.
Have students cut two leaves from the bean
plant, open the container, and place them
inside on the wet paper towel. (The towel will
help keep the leaf from wilting). Next, have
them transfer ten aphids from the bean plant
onto the bean leaves in the container. Tell
them to use the pipe cleaners, as before, to
transfer the aphids.
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Tell students to place the label on the side,
not on the perforated lid, of the container so
as not to cover the air holes.
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Remind them to handle the aphids gently
and avoid disturbing the ladybugs. If poked
and prodded, ladybugs may lift their wing
covers, spread their wings, and fly, though
they are generally slow to do so.
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Have students snap the covers back onto the
containers without delay so that the ladybugs
will not escape.
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Allow time for students to observe the
behavior of the ladybugs in the container
(see Figure 37-2).
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activities 37 & 38 Land Predators
Figure 37-2. Ladybugs and aphids in container.
Some ladybugs may attack aphids
immediately, but others may not.
© Delta Education. Photocopying and distribution prohibited.
Have students record in the population chart
on their activity sheets the observation day
(0), today’s date, and the number of aphids
and ladybugs in their team’s container.
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Guiding the Activity
Additional Information
Tell students that they will be observing the
ladybugs and aphids for the next few days to
see what happens.
4
Remind students that scientists usually make
predictions, or guesses, about what they
think will happen in their experiments based
on what they already know. Ask students to
predict whether the ladybugs will eat the
bean leaves or the aphids, and have them
circle their choice on their activity sheets.
Discuss students’ predictions by asking, How
many think the ladybugs will eat the bean
leaves? Why or why not? How many think
the ladybugs will eat the aphids? Why or
why not?
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Accept all student predictions and
explanations, encouraging them to articulate
their opinions fully.
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Return the foam cups containing bean plants
and aphids to their place in the classroom,
and place the containers with the ladybugs
and the aphids in a place out of direct
sunlight and away from any heat source.
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If students are concerned about making an
inaccurate prediction at this point, remind
them that scientists often do not know
exactly what will happen before they do their
experiments.
Replace the transparency in the kit. Collect
the magnifiers and pipe cleaners and return
them to the kit. Collect the activity sheets for
use in the continuing observation sessions
and Session II.
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Every day for 3 days, return each student’s
activity sheets. Distribute magnifiers and
their labeled containers with leaves, aphids,
and ladybugs to each team.
Have students examine the containers, count
the number of aphids in each, and look for any
signs that the ladybugs have been eating the
leaves. Have students record this information
in the population chart on the activity sheet.
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Guiding the Activity
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Additional Information
Session II—Activity 38
At the end of the third and final day of
observation, return their activity sheets to
students. Distribute magnifiers and their
containers with aphids and ladybugs to each
team. Have them observe and record their
observations on their activity sheets.
Revisit the idea of interdependency between
plants and animals. Ask, How do the
ladybugs depend on the aphids for
survival?
Remind students that many animals depend
on other animals for food. Then ask, How do
the ladybugs depend on the bean plants for
survival?
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The ladybugs depend on the aphids as a
source of food.
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Students should see that without the bean
plants, the aphids would die. With no aphids
to eat, the ladybugs would die.
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Write predator and prey on the board. Explain
that a predator is an animal that eats another
animal, and the prey is the animal that is
eaten.
Ask, Which is the predator in your
container, the ladybug or the aphid? Which
is the prey?
The ladybug is the predator, and the aphid is
the prey.
Ask, What do you think would happen to
the population of aphids on the bean plants
if you added a ladybug to each plant?
Students should be able to say that the
aphid population would decrease as the
ladybugs ate the aphids on the bean plants.
Ask, How does a predator change the
population of its prey?
A prey population decreases when a predator
is present.
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Allow students time to complete their activity
sheets.
As appropriate, read or review pages 11–13
from the Delta Science Reader Plant and
Animal Populations.
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Since there are fewer aphids left in the
containers, students should be able to say
that the ladybugs seem to be eating the
aphids. (Some students may have actually
seen the ladybugs doing this.)
activities 37 & 38 Land Predators
© Delta Education. Photocopying and distribution prohibited.
Ask, What do you think the ladybugs are
eating? What do you see that makes you
think so?
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REINFORCEMENT
CLEANUP
Have students add fresh bean leaves to the
containers with the ladybugs and continue to
monitor the aphid population daily to see if
the aphid population continues to decrease.
SCIENCE JOURNALS
Have students place their completed activity
sheets in their science journals.
Collect the magnifiers and return them to
the kit. Replace the ladybugs in their
shipping container for use in further
experiments, if desired. Refer to pages
288–289 for more information on how to
handle living materials after completing
the unit.
SCIENCE AT HOME
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If weather permits, have students examine
shrubbery near their homes to look for
ladybugs. If they find any, challenge them
to also look for the aphids or other tiny
insects that the ladybugs are preying on.
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Connections
Science Extension
Science and Social Studies
Students may wonder whether any animals
eat ladybugs. Tell them that ladybugs have
a very bad taste. The ladybug’s bright color
is a warning to other animals that it may
not be good to eat. Ladybugs also defend
themselves by rolling over on their backs and
staying still if they are disturbed. Students
may like to test this reaction by gently poking
one of their ladybugs with a pencil point to
see whether it will “play dead.”
Students might like to find out about some of
the world’s largest insects and where they are
found. An excellent source of information is
The Big Bug Book by Margery Facklam (Bt
Bound, 1999). The realistic illustrations by
Paul Facklam show thirteen different insect
“giants” at their actual size. Help students
find the native locations of the insects on a
globe.
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Science, Technology, and Society
With their bright colors, dramatic black spots
and head, and rounded shape, ladybugs
make excellent subjects for an art project
with papier mâché. Give each pair of students
a round balloon, and tell them to blow it up
and tie off the end securely. Provide papier
mâché mixture (a thick “soup” of wallpaper
paste and water) and newspaper torn into
strips, and have students cover their balloons
with several layers of soaked strips. When the
papier mâché is thoroughly dry, help each
pair cut the shape in half lengthwise to make
two half-round bases for the ladybug models.
Provide paints and craft supplies such as
black pipe cleaners so students can complete
their models. To create a dramatic classroom
display, students could also make aphids and
a plant from papier mâché, then set up all the
models to show the predator ladybugs eating
the prey aphids on the plant stem.
Prompt students to recall their discussions
with gardeners about aphids and other insect
pests damaging their gardens (Science,
Technology, and Society, Activity 36). Ask
students to describe any biological controls
that the gardeners may have tried. If students
do not mention it, tell them that some
gardeners purchase ladybugs to put in their
gardens. Ask students why they do this. (so
the ladybugs will eat destructive aphids) Ask
why using ladybugs to control the aphid
population would be better than simply
spraying the garden with insect poison.
Accept all reasonable responses, then read
aloud the children’s book What About
Ladybugs? by Celia Godkin (Bt Bound, 1999).
This beautifully illustrated book is a fictional
account of one gardener’s attempt to control
insect pests with poisons initially, with
disastrous results for the garden, and then
naturally with ladybugs.
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Science and Language Arts
Obtain children’s books about ladybugs to
read aloud to small groups or to make
available for students to read on their own if
they are capable.
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activities 37 & 38 Land Predators
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Science and the Arts