Pollination and Fertilization
Purpose:
To understand what occurs during the pollination and fertilization process. To identify
the roles of the stamen (anthers, filament, and pollen); pistil (stigma, style, ovary, and ovule); and pollinators such as wind, animals, and
gravity in both these processes. To learn about the two classes of flowers--animal-pollinated
and wind-pollinated--with respect to pollination and their features.
Overview:
The children will be physically demonstrating the pollination and fertilization process of flowers. Each child will have a part to play during this role-playing.
Objectives:
As a result of this activity, children will be able to:
- Understand and demonstrate how flowers reproduce through the pollination and fertilization process.
- Classify flowers according to their features and how they are pollinated.
- Identify the parts of the flower involved in the fertilization process.
- Appreciate and demonstrate working in a cooperative group.
Materials:
- Small ball: handball (pollen) (one per group)
- Medium-sized ball: softball (egg) (one per group)
- Large ball: basketball (seed) (one per group)
- Science journals
- Video camera
- The Magic School Bus Goes to Seed (video or book)
Motivation:
- If you have the Magic School Bus Goes to Seed video or book, review it with the students before conducting the lesson. Otherwise, explain the fertilization process and the flower parts that are involved in this process. Have them refer to the "Flower Structure" sheet from the previous lesson. It would be helpful if you had a large version of the sheet with the parts filled in.
- Ask the children how they think the pollen travels from the anther to the stigma. Then explain that, depending on the type of flower, pollination might require wind, animals such as birds, or even gravity.
- Explain that there are two different classifications of flowers regarding pollination. One is animal-pollinated flowers, which attract pollinators such as birds, moths, butterflies, and bats. These flowers possess nectar guides such as colors, scents that alert animals, of the nectar inside the flower. Wind-pollinated flowers lack showy petals or sepals, and the stigmas and anthers are elevated to easily catch and release pollen.
Procedure:
- Divide the students into groups of four and provide a scenario on a piece of paper for each group to enact. For example, one group can demonstrate a pollination and fertilization process that requires a bird to pollinate the flower, while another might need wind. Each group needs to keep their scenario secret from the rest of the groups. No talking is allowed in the performances.
- Allow each group at least twenty minutes to plan their skit and also give each group three different-sized balls to represent the egg, pollen, and seed.
- Videotape each group's performance as documentation of their work.
Conclusion:
After each group has performed, ask the rest of the class what they think they have just witnessed. Since each group has a different scenario, all of the groups will look different during the enactment of the pollination process. Discuss each scenario with the class and ask them to classify the flower from each scenario. List these on the board under two headings: animal-pollinated and wind-pollinated flowers.
Follow-up:
For homework, ask the children to write a story about a flower and how it gets pollinated and fertilized.
Assessment:
The videotape of each group's performance and the homework will be used to assess the students' ability to work in a cooperative group as well as their ability to describe the pollination and fertilization process.
Extension:
Students will be creating flower models that represent wind-pollinated and animal-pollinated flowers. They will identify them and write about how each of their flowers demonstrate the features of a wind- and animal-pollinated flower.
Background:
Pollen, developed in the anthers, contains sperm cells. Depending upon the type of flower, the pollen is either carried by wind or animals to the stigma. Once the pollen reaches the stigma, it forms a pollen tube, which grows down through the style toward the ovule in which the sperm cells travels through. Once the pollen tube reaches the ovule, fertilization between a sperm cell and an egg may occur.
Features of Animal-Pollinated Flowers
- They have nectar glands that produce a sugar-water solution, which attracts birds and insects.
- They possess nectar guides (colors, scents, and even lines on petals that alert pollinators to the presence of nectar) to encourage pollinators to crawl into the flower, picking up or transferring pollen among flowers.
Features of Wind-Pollinated Flowers
- They have no showy petals or sepals.
- Stigmas and anthers are elevated to allow wind to carry or deposit pollen.
- Many flowers are wind-pollinated, such as grasses; cattails; and maple, oak, and pine trees.
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Lessons:
Inside a Flower
Soil Investigation
Flower Investigation
Fruit or Vegetable?
Where Am I?
Seed Dissection
Flowers Galore
Pollination & Fertilization
Flowers & Their Families
Plant Parts & Their Jobs
Identifying Flower Families through Flower Shapes
Brooklyn Botanical Garden Scavenger Hunt
Bibliography
This lesson is part of Flower Power by Rosemarie Young.
Grade Levels:
3-5
Subjects:
Science, Math and Arts, writing
Beginning Grade
Level:
3
Ending Grade Level:
5
e-mail Rosemarie
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