The Reason for a Flower Flower Dissection

Overview: Dissect a lily to learn the different parts of a flower. Discover how pollination works.

Objectives: Identify the parts of a flower, including petal, sepal, carpel, stigma, style, ovary, stamen, anther, and pollen. Describe the major functions of the parts of the flower.

Links to Iowa Core: Life Science (Grades K-2): Students will understand and apply knowledge of life cycles of plants and animals. Life Science (Grades 3-5): Students will understand and apply knowledge of organisms and their environments, including structures characteristics, and adaptations of organisms that allow them to function and survive within their habitats. Life Science (Grades 6-8): Students will understand and apply knowledge of how different organisms pass on traits.

Time: 30 minutes but could be enriched for a longer lesson or series of lessons.

Materials: . Large flower (ex. Lily) . Cutting board . Scalpel or razor blades (optional) . Magnifying glass . Microscope . “Parts of Flower” handout . Tape . Pencils

Procedure: 1. Introduction: Do you know the reason for a flower? Flowers are specialized to help plants reproduce. Without flowers, most plants would not be able to make new plants. There is a female part and a male part to a flower. The female part is the center and is made up of the ovary, stigma, and style. The stigma is sticky and captures the pollen from other flowers. The pollen germinates on the stigma and travels down the style to the ovary. Once the pollen reaches the ovary, it combines with the female gamete (egg) to make a seed or ovule. The male part of the flower is the anther, stamen, and filament. The anther carries the pollen, which fertilizes the female parts of the flower. The stamen and the filament hold up the anther. The petals are colorful and help attract pollinators. Sepals are like petals, usually attaching below the petals on the receptacle. The receptacle is the part of the flower that is left once the flower has been fertilized, and the petals fall off. This part of the flower swells as the seeds develop. The peduncle is the junction between the receptacle and the stem of the flower. 2. Split the class into groups of 2 or 3. Hand each group a dissection kit, parts of flower handout, and a flower. Be sure to keep one flower for you to use as a demonstration. 3. Using the scalpel or your hands, carefully pull apart or make a vertical incision to open the flower. 4. Use the handout to identify and label the sepals, petals, stamen, anther, filament, stigma, style, ovary, and pistil. After identifying each one pull off an example to tape to your handout. 5. With the hand lens examine the anther to see if it is producing pollen. The students may also take turns using a microscope to get a closer look at the anther. 6. Look inside the ovary. Can you see ovules or seeds? 7. Once everyone is finished collect plant material and dispose of it in the designated area.

Discussion: Ask the class the following questions: What is the reason for a flower? What role do the different flower parts play in pollination? For example, what is the purpose of the petals? Why is pollination important to a plant’s survival? How do you think color, shape, size, patterns, and scent affect pollination?

*For younger students, focus more on the basic structures of a flower and allow more free time to examine the flower. You could read the book, The Reason for a Flower by Ruth Heller, to introduce or conclude the lesson.*