Download 03_U2_L2 Hybrid Seeds

Unit 2: Seeds: The Record-Keepers
Lesson 2: Pollination and Hybrid Seeds
Grade Level: Third Grade
Time Required: 45 – 60 minutes
Primary AZ State Standards:
(Cross-reference “Standards Matrix” for full listing)
Science:
S03-S3C1-02: Describe the beneficial and harmful impacts of natural events
and human activities on the environment.
S03-S4C1-01: Describe the function of the following plant structures:
-flowers, attract pollinators and produce seeds for reproduction.
Objective(s):
Students will examine flowers and identify flower parts involved in pollination.
Students will create a hybrid fruit or vegetable.
Students will analyze the environmental and financial impacts that seed company
technologies have in our society.
Materials:
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Key Vocabulary:
A variety of flowers for dissection
Tweezers
Hand lenses
Appendix 3J: Flower Parts
Blank paper
Crayon, colored pencils, and/or markers
Plastic Easter eggs
Appendix 3K: Egg Inserts
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Hybrid
Pollinate
Stamen
o Anther
o Filament
Pistil
o Stigma
o Style
o Ovary
Petals
Sepals
Terminator gene
Instruction Features
Preparation
Scaffolding
_X_ Adaptation of Content
_X_ Modeling
___ Links to Background
_X_ Guided Practice
_X_ Links to Past Learning ___ Independent Practice
___ Strategies Incorporated _X_ Comprehensible Input
Grouping Options
_X_ Whole Class
___ Small Groups
_X_ Partners
___ Independent
Integration of Process
_X_ Reading
_X_ Writing
_X_ Speaking
_X_ Listening
Assessment
__ Individual
__ Group
__ Written
__ Oral
Application
_X_ Hands-on
_X_ Meaningful
_X_ Linked to Objectives
_X_ Promotes Engagement
Background Information:
As much as we would like to believe that flowers were created for our
enjoyment, the truth is that flowers are actually solely to ensure seed creation.
Flowers lure in pollinators with their attractive petals and smells to pollinate and
fertilize seeds. Only through the process of pollination will plants produce the fruits
and vegetables of which we are so fond.
Flowers have several key parts which students should review for this lesson.
(Willow Bend Environmental Center does a program called “Reason for a Flower” which
would be a great class for students to have prior to this lesson. The Arboretum at
Flagstaff also offers a 4th grade program on “Pollination” that would reinforce these
same concepts.) Flowers have both male and female parts. The female parts are
contained in the pistil. The parts of the pistil are called the stigma, the sticky top
part that catches pollen; the style, a tube that lead down to the ovary; and the
ovary, which is where the seed grows safely protected. The male parts are contained
in the stamen. The stamen consists of the anther, which is a ball like structure
which produces pollen, help up by the filament. Pollination occurs when the pollen
is transferred from the male flower parts to the female flower parts. The tiny grain of
pollen either flies on the wind or is carried by a pollinator to the sticky stigma, is
transferred down the style into the ovary where it fertilizes an egg and becomes a
seed.
Heirloom seeds, as discussed in Lesson 1 of this unit, are open-pollinated,
which means that pollination occurs naturally in the field. Seeds from heirloom
plants can be harvested and replanted year after year, reliably producing offspring
that exactly resemble their parent plants.
Hybrid seeds, however, have been artificially cross-pollinated with the goal of
producing more durable, resistant, tasty, or attractive plant. People who create
hybrids choose different plants to breed together based on qualities of each that they
wish to preserve. Unfortunately, because the breeding is unnatural, the next
generation of seeds from hybrid plants cannot be relied upon to produce exact copies
of their parent plants. As a result, hybrid plants can only be reliably grown from first
generation hybrid seeds produced by seed companies.
One seed company in the United States has taken the process of hybrid seed
manufacturing step further. They have introduced a terminator gene into seed
development that causes subsequent seeds to become sterile, which means the seeds
won’t even grow a new plant. The scary thing about this terminator gene is that it can
be genetically transferred to other plants through open pollination, by traveling
within pollen on the wind, to other non-hybrid plants in the environment. When this
happens, then the newly contaminated plant will begin producing sterile seeds. The
seed company’s goal is to force farmers and gardeners to buy new seeds from them
every year, not save seeds and replant on their own. For more information about this
new technology, please see http://www.organicconsumers.org/monlink.cfm.
Pre-lesson Preparation:
1. Print out Appendix 3J, cut up labels and distribute among plastic easter eggs.
Activity Instructions:
Flower Function Review and Exploration
Whole class, individual
5- 20 minutes (can be shortened to a simple 5 minute review if students have
recently learned about flower parts and functions)
1. Gather students as a whole group. Pass around flowers, have students inspect
them and answer the question, “What purpose to flowers serve?”
2. Have students freeze with whatever flower they have in their hand and take
them back to their desks.
3. Explain that everyone is going to look at their flower with the hand lens and
describe the parts they see.
4. As students find the parts of the flower, ask them what they think those parts
do.
5. After some discussion, show Appendix 3J and discuss the parts of the flower.
6. Discuss open-pollination versus hybrid pollination.
Creating a Hybrid
Partners
20 minutes
1. Tell students, “So imagine you are a seed company. What kind of new plant
would you make if you could? The best inventions are ones that are driven by
people’s needs. What kinds of fruits and vegetables do you think people need?”
2. Explain and model the task with an example hybrid (strawberry/banana).
a. Students will work in pairs for 10 minutes to design a new fruit or
vegetable by mixing qualities of different fruits or vegetables.
b. Students should name their creation and be ready to “sell” it to the class
as if they were the seed company.
c. Students should also figure out how much they wanted to charge for a
package of their seeds.
3. Put students in pairs.
4. Distribute blank paper and drawing/coloring tools. Give them 10 minutes to
work.
5. After 10 minutes, have students share creations.
6. Ask students, “So what would happen to your company if people bought one
pack of seeds, planted 10 or 20 plants, and then just collected the seeds from
those plants and planted them again?” If the seeds were viable and
produced offspring that were identical to the parents, people wouldn’t
need the seed companies anymore.
The Impact of Seed Company Technologies - Simulation
Whole class
20 minutes
1. Tell students, “This next activity is to get you thinking about the challenges
that seed companies have and the solutions we need to find together to make
sure our ecosystems don’t get hurt.”
2. Get students back together as a whole group.
3. Ask the group, “As a seed company, what would you do to make sure that
people keep buying seeds from you?”
4. Tell students the information about terminator genes as explained in the
Background section. Before revealing to students how ecologically
damaging this technology could be, have them predict how they think it
would affect seed companies and how it would affect the environment.
5. Tell students, “To get a better understanding, we are going to an activity now to
help you think about the financial and ecological impacts that seed company
technologies may have.”
6. Explain the activity to students.
a. The teacher will place Easter eggs all over the room. The Easter eggs are
actually “the flowers” that contain the plants’ seeds. The flowers will
either have heirloom seeds, hybrid seeds, or seeds that contain the
terminator gene. They will also have information that the
farmer/gardener needs to know (See Appendix 3K for inserts).
b. Students will walk over to a place where there is an egg and stay there
with the egg.
c. Students will open up their flowers (eggs) and read their information, and
complete any activities that may be required.
d. Finally, students will share information they learned.
7. The key to this activity is that any student that opens an egg with a terminator
gene will sterilize all heirloom (and hybrid) seeds within a 15 foot radius. You
can adjust this distance as needed. Encourage students to actually measure
out this distance with a tape measure, string or yard stick.
8. In closing, ask students:
 What affects might these seed company technologies have on gardeners’
and farmers’ bank accounts?
 What affects do the technologies have on the seed companies’ bank
accounts?
 What affects do the seed company technologies have on the
environment?
 What do you think you, as a gardener, should do?
Resources:
Organic Consumers Association Website. Accessed June 18, 2010 from
http://www.organicconsumers.org/monlink.cfm.