Operation Flower Dissection

Transcription

1 Operation Flower Dissection Classroom Activity: K-4 Time: One to two 50-minute class periods Overview: In this activity, students will observe the similarities and differences between flowers of different plants. They will also learn the anatomy of a flower. Note: This lesson, Operation Flower Dissection, is one in a series of lessons introducing basic plant parts and functions. Other lessons cover root structure and function, seed function and dispersal, movement of water in stems, and breathing or the exchange of gases in leaves. Integration with Project BudBurst Elementary school students participating in Project BudBurst study plants in their schoolyard environment and learn to make careful observations of the timing of leafing, flowering, and fruiting of selected plants. In conjunction with teaching students to make observations of living plants, teachers may also introduce basic plant anatomy, a topic typically covered at this age. The lessons in this series on plant parts and function may be used as an introduction to participation in Project BudBurst, to help set the stage for what students will be observing. Alternatively, teachers may use these lessons in between times students make outdoor observations to extend their understanding of what they are observing. For example, as students observe flowering, teachers may use this lesson Operation Flower Dissection to help students understand the structure and function of flowers. Page 1 of 5

2 Learning Outcomes: Students will be able to: Identify parts of a flower including sepals, petals, pistils, stamens, and where the seed forms. Compare similarities and differences of flower parts on different varieties of flowers Describe the simple functions of each flower part, and the role of flowers in reproduction. Explain that plants use different flower designs to attract pollinators. Materials: One-half class set of a single variety of flower One-half class set of a mixture of 10 different varieties of flowers One-half class set of tweezers Cotton swabs Tape Book or poster showing the parts of a flower, or copy the diagram from this activity onto an overhead transparency Education Standards: Available at: Preparation For the first dissection activity, place the same-variety flowers on contrasting color construction paper. Write the plant s common name on each piece of paper. For the second dissection activity, place the different-variety flowers on contrasting color construction paper. Write each plants common name on its piece of paper. Page 2 of 5

3 Activity 1) Use the largest same-variety flower to demonstrate to the class how to dissect a flower. Show the students a labeled illustration of the parts of a flower to help identify the flower parts. You can use the diagram from this activity, or find a poster or book with this illustration. 2) First count the number of sepals the flower has and record this number on the construction paper. Then, use tweezers to remove the outer green petal-like structures called sepals. Tape them to a piece of construction paper and label. Try to arrange the parts on the construction paper in the same general arrangement as that shown in the illustration. 3) Next remove the petals, the stamens, and the pistil, again counting the number of each part and recording this. Carefully tape and label them on the paper (e.g., 4 petals). 4) Before taping the stamens, shake some of the pollen grains from the anthers onto the paper and tape down. 5) Give student pairs one each of the same-variety flowers on a piece of construction paper and tape. Have them follow your procedure to dissect their flowers, counting parts as they go and taping the parts to a piece of construction paper, and labeling. Explain that any differences among the flowers, such as size, are not important because all the flowers being dissected belong to the same variety. 6) Next, give student pairs one each of the ten different-variety flowers on another piece of construction paper. Have them follow the same procedure for dissecting, taping, and labeling. 7) Have students compare the differences among the flower varieties. Are all the flowers complete with sepals, petals, stamens, and pistils? Do the parts from different flowers have different shapes? Are there different amounts of various parts? Suggested Extension Activities Have students look at a compound flower with a magnifying lens. Some examples of compound flowers are sunflowers and daisies. Have them closely examine the flower to see if they can find the pistils and stigmas of the inner disc flowers and the single petals of the outer ray flowers. Observe the process of pollination in a garden. For classes participating in Project BudBurst, students may dissect their study plant s flower and make a similar arrangement on construction paper. Page 3 of 5

4 Background Information Flowers are the reproductive parts of a plant. The flower is where the seed is made, and each flower s design can use size, shape, scent, and color to help carry out this mission. Plants that depend on pollinators to reproduce make their flowers an invitation to come visit. The sepals are small, green floral parts that protect the developing flower bud like a suit of armor. They are the outermost flower parts. When the flower blooms, the sepals usually remain green and are thicker than the petals. Petals function to attract pollinators. They use their shape, size, and color to attract bees, butterflies, and birds to their nectar. Stamens are the male part of the flower that make and hold the pollen. Stamens consist of a filament growing with a pollen-bearing anther. Stamens can stand free or are sometimes fused together. A pistil is the female part of the flower. It has a sticky top (stigma) to capture pollen. Once the pollen is on the pistil it travels down to the ovary and fertilizes the waiting egg, with eventually forms a seed. A pistil consists of an ovary, which contains the egg-bearing ovules, and a style, the elongated tube connecting the sticky stigma to the ovary. When trying to identify the male and female structures in flowers, certain kinds of flowers will initially pose a challenge. Most members of the sunflower family have a daisy type flower composed of two different types of flowers. For example, the black eye of the Black-eyed Susan is actually composed of many disc flowers surrounded by the outer ray flowers. Student Assessment Suggestions Teachers may have students make drawings of flowers including labels for each of the parts. They may also have students sketch their Project BudBurst flower, including labels for each of its parts. As students will be observing their plant over time, teachers may have students draw the flower bud as it develops. Source: Adapted from Exploring the Native Plant World, developed by the Lady Bird Johnson Wildflower Center in Austin, Texas and Teaching Plants from Root to Seed, developed by the Denver Botanic Gardens in Denver, Colorado This teacher resource was made possible, in part, by support from the National Geographic Education Foundation. Page 4 of 5

5 Image courtesy of ECO/Alison Perkins Page 5 of 5