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Anytime Lesson Plan: Flowers Seeking Pollinators

Abstract

In this lesson, students will learn that many plants depend on animals for pollination and many pollinators depend on plants for food. They will also learn that flowers, which have male and female parts, are structures for reproduction and that flowers are adapted to attract specific pollinators.

Objectives

In this lesson, students will:

  1. learn that many plants depend on animals for pollination and many pollinators depend on plants for food.
  2. learn that flowers, which have male and female parts, are structures for reproduction.
  3. learn that flowers are adapted to attract specific pollinators.

Materials

  • various art supplies for making flowers, for example:
    • construction paper
    • colored cellophane or tissue paper
    • portion cups
    • pipe cleaners
    • string
    • hole punchers
    • tape, glue, or staplers
    • crayons or markers
    • scissors
  • 2-sided Flowers Seeking Pollinators worksheet (print 1 per student)
  • Flower Diagram (print 1 per pair or small group)
  • Flowers Seeking Pollinators: Answer Key (print 1 for teacher)
  • optional: materials for pollination demo or role play (real flowers, sticky dots, etc.)

Vocabulary

  • adaptation: a living organism’s physical/behavioral features that aid it in surviving within a specific habitat.
  • angiosperm: flowering plants (pines, ferns, and mosses are not angiosperms)
  • flower: the reproductive structure found in flowering plants (angiosperms).
  • nectar: a sweet liquid secreted by flowers as an attractant and reward for pollinators.
  • pollen: a powder-like substance in a flower (or cone) that is made up of grains.  Each grain functions as a capsule for carrying the male gametes (sperm cells) of the plant; during pollination, pollen is moved from the stamen of a flower to the stigma of a flower.
  • pollination: a necessary step in the reproduction of flowering plants; the process by which pollen is transferred from the male stamen to the female stigma, thereby enabling fertilization and sexual reproduction.
  • pollinator: an animal (e.g. insect, bat) that involuntarily transfers a flower’s pollen from male reproductive organs to female reproductive organs.
  • stigma: the pollen-receiving tip of a flower’s pistil (female part).
  • stamen: the male pollen-producing reproductive organ of a flower.

Activity

Preparation

  1. Print and copy Pollinator Worksheets (1 per student).
  2. Print 1 Pollinator Answer Key for yourself.
  3. Print and copy Flower Diagram (1 per pair or small group).
  4. Depending on student seating arrangement, divide art supplies among student tables or place the art supplies in one central location.

Introduction to Pollination

(time spent will vary based on prior knowledge)

  1. Ask students questions such as, “What are your favorite flowers?” “Are plants trying to win a beauty contest?”  “Why do plants have flowers?”  For reproduction!
  2. Hand out the Flower Diagrams.  Flowers have both male and female parts.  Pollination is achieved when the pollen from the male part, the stamen, is transferred to the female part, the stigma.  This can happen between the male and female parts of one flower (self-pollination) or between separate flowers of the same species (cross-pollination).  Flowers can’t do it themselves.  What in the natural world can help move the pollen?  Animals, wind, or water!
  3. Why do pollinators (e.g. birds, insects, bats) visit flowers?  Most feed on the nectar (a sugar-rich liquid) of a flower.  The nectaries are usually located deep in the middle of a flower so that pollinators have to brush against the anthers (male, pollen-containing tips of stamens) and the stigma to get to the nectar.  Some pollinators, like bees, need pollen in addition to nectar.  Some pollinating insects (e.g. some flies) are attracted to flowers by scent but gain no reward when they visit.  The insects try to leave quickly but the flowers may have traps to slow the insects down.
  4. It may be useful to ask a few students to role-play the pollination process.  Teachers may also choose to bring some flowers into class and ask students to “hand-pollinate” them.

 

Pollinator Worksheet

  1. Hand out the Pollinator worksheet.  Refer students to side entitled “Flowers Seeking Pollinators”.
  2. Go over the information as a class.  Note that, flowers have evolved to attract pollinators in many different ways.  Color, shape, and smell are the dominant strategies.  Highlight that some flowers and pollinators are specialists and others are generalists.  For example, certain orchids can only be pollinated by certain insects (specialists) while other flowers can be pollinated by several different birds and insects (generalists).
  3. Instruct students to complete the back of the worksheet (Flower-Pollinator Matching) individually or in small groups. 

Make a Flower Activity

  1. Students now use art supplies to make their own flowers.  Each student’s flower should be adapted to attract at least one type of pollinator.  Students may want to create flowers that attract multiple pollinators, as well.  Students should be prepared to share about their flowers.  They should consider whether the flower will have an odor and whether it will be open at all times of day/ night.
  2. Once students have had a chance to construct their flower, have them place them on a table with a label that describes where the flower is found (i.e. at the top of a tree, near the ground, etc), and what it smells like.
  3. Then, assign a specific type of pollinator to each person, giving them an associated colored marker (i.e. black for bats, red for butterflies, yellow for bees, etc.). The class then can swarm around, looking for appropriate flowers, and marking a dot on the paper label next to the flowers they are attracted to. Emphasize that students can only go to the flowers that they think will attract the animal they are representing.
  4. As a teacher, observe the students.  If there are any flowers that people seem confused by, or any pollinators that are confused, have your class pause to discuss them.
Finished flowers!

Wrap-Up

  • Have students present their flowers to the class. 
  • Highlight that these evolutionary changes do not happen overnight.  It takes hundreds and thousands of years for these adaptations to take shape.
  • Ask students how the pollinators may be adapted to the flowers. 

Extensions

  • For a group that needs more teacher facilitation, rather than have students label the flowers with markers, you can have the class guess which pollinator the flower was intended for during the student presentations.
  • You may choose to extend this lesson and delve more deeply into flower anatomy at the beginning.  Flower dissections work well for this.
  • If students are advanced, you can extend the lesson through an exploration of co-evolution.  Challenge students to research pollinators and find out the ways in which the pollinators themselves are adapted to certain flowers.

References

California Content Standards

Grade Three

Life Sciences

  • 3a. Students know plants and animals have structures that serve different functions in growth, survival, and reproduction.

Grade Four

Life Sciences

  • 3a. Students know many plants depend on animals for pollination and seed dispersal, and animals depend on plants for food and shelter.

Visual and Performing Arts

  • 1.1 Perceive and describe contrast and emphasis in works of art and in the environment.
  • 1.5 Describe and analyze the elements of art (e.g., color, shape/form, line, texture, space, value), emphasizing form, as they are used in works of art and found in the environment.

Grade Six

Ecology (Life Sciences)

  • 5c. Students know populations of organisms can be categorized by the functions they serve in an ecosystem.

Grade Seven

Structure and Function in Living Systems (Life Sciences)

  • 5f. Students know the structures and processes by which flowering plants generate pollen, ovules, seeds, and fruit.

 

Background

The plant life cycle (for flowering plants)

For most plants to reproduce, they go through pollination, create fruits, and disperse seeds.  For the students, it is useful to describe the process in four steps: flower, pollination, fruit, and seed dispersal.  In some cases, plants do not need animals for pollination or seed dispersal.  In other cases, plants rely on animals for both processes and must attract each animal in a different way.

  1. Pollination: Pollination is the transfer of pollen from the stamens to the stigma of flowers.  Pollen can be carried by insects, other animals, wind, or water.  Self-pollination refers to the process in which pollen lands on the stigma of its own flower or another flower on the same plant.  Cross-pollination refers to the process where pollen is transferred to the stigma of a flower on another plant of the same species
     
    Since ovules within the same plant can differ genetically from one another, self-pollination can result in some variation in the offspring.  Cross-pollination, in which genetic material comes from two parents, results in greater variation and is therefore considered advantageous.
     
  2. Fertilization: Once the pollen grain reaches a compatible stigma, it receives a chemical signal from the stigma.  The pollen then produces a tube, which grows down through the style, into the ovary, and into one of the ovules.  This allows the male pollen cell to fuse with the female cell inside the ovule.  This process if called fertilization.  Afterwards, the ovule develops into a seed. 
     Flower Structures
  3. Formation of the fruit:  After fertilization has occurred, the ovule develops into a seed.  The seed(s), surrounded by the ovary wall, develop into the fruit.  In some plants, other parts of the flower may also help to form the fruit.  Many of the seeds formed inside the fruit do not land in a suitable place for germination or do not survive the early stages of growth.  Plants produce large numbers of seeds in order to make sure that at least some of the new plants survive.
     
  4. Seed Dispersal: To avoid overcrowding and reduce competition for light, water and mineral salts, the seeds must spread away from the parent plant and from each other.  Seed-containing fruits disperse in four ways:
    • Animal dispersal.  Animals may eat the fruits and drop seeds in other places.  The seeds may also pass through the animal’s digestive system and be deposited in the animal’s feces.  Some fruits are covered in hooked bristles that cling to an animal’s fur (or your socks) and ensure that the seeds get carried elsewhere.
    • Wind dispersal.  Some seeds are small enough to float in the air.  Others have special structures, comparable to wings or parachutes, which keep them airborne for a longer period.
    • Water dispersal.  The seeds of these plants (found in or near water) are buoyant.
    • Self dispersal.  As some fruit ripens, the fruit wall dries and twists until the two halves of the fruit wall are pulled violently apart and the seeds shoot out.  Other plants, such as the poppies, produce capsules full of small seeds.  When the seeds are ripe, small holes develop around the top of the capsule and the seeds get knocked out by wind and passing animals.  This process is nicknamed “pepperpot.” 

Pollinator Syndrome Traits Table

(retrieved from http://www.fs.fed.us/wildflowers/pollinators/syndromes.shtml)

This pollinator syndrome trait table can help you identify the flower traits associated with certain pollinators. These are general trends and cannot be applied strictly to all flowers.

TraitPollinator
BatsBeesBeetlesBirdsButterfliesFliesMothsWind
ColorDull white, green or purpleBright white, yellow, blue, or UVDull white or greenScarlet, orange, red or whiteBright, including red and purplePale and dull to dark brown or purple; flecked with translucent patchesPale and dull red, purple, pink or whiteDull green, brown, or colorless; petals absent or reduced
Nectar guides (patterns on petals guiding pollinators to the nectar)AbsentPresentAbsentAbsentPresentAbsentAbsentAbsent
OdorStrong musty; emitted at night Fresh, mild, pleasantNone to strongly fruity or fetidNoneFaint but freshPutridStrong sweet; emitted at nightNone
NectarAbundant; somewhat hiddenUsually presentSometimes present; not hiddenAmple; deeply hiddenAmple; deeply hiddenUsually absentAmple; deeply hiddenNone
PollenAmpleLimited; often sticky and scentedAmpleModestLimitedModest in amountLimitedAbundant; small, smooth, and not sticky
Flower Shape Regular; bowl shaped – closed during dayShallow; have landing platform; tubularLarge bowl-like, MagnoliaLarge funnel like; cups, strong perch supportNarrow tube with spur; wide landing padShallow; funnel like or complex and trap-likeRegular; tubular without a lipRegular: small and stigmas exerted

 

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