Reach For the Sun Teacher Guide - Plant Life Cycles and Reproduction

Plant Life Cycles and Reproduction

Time Required

2 CLASS PERIODS

Objectives

Students will investigate plant life cycles and reproduction by observing fruits and by germinating seeds.

Materials

FOR THE STUDENT

FOR EACH GROUP OR PAIR

Computer and Internet accessPeas, strawberries, tomato slices, banana slices3 to 4 whole lima bean seeds1 lima bean seed split in half lengthwiseClear plastic baggiePaper towelInch rulerStapler1/2 cup of water

Preparation

Remove the lima beans from the water and cut one in half lengthwise for each group.
Prepare fruits for each group by placing one or two samples of each type on a paper plate or tray.
Set up an interactive whiteboard or make copies of the Flowering Plant Life Cycle Diagram and the Monocot Dicot Diagram in the Appendix.

Plant Growth Observations

Have students make observations of their plants from the lab in Lesson 1 and record their observations on the Lab Sheet.

Game Play!

Have students play Reach for the Sun with their partners for approximately 30 minutes.

  • Students can try the Strategy mode this time. Strategy mode will allow students more time to think through the way they allocate resources.
  • Allow students to play without pausing, but ask them to think about how the Strategy mode and the Classic mode are different. Also ask students to think about what they have learned about plant life cycles by playing the game.

Pause and Think

Have students complete the discussion questions in the Student Guide. Then ask students to share their responses with the class. Circulate as students play and ask them some questions about plant life cycles:

  • Why is it important for plants to reproduce before the growing season ends?
    The plant will die at the end of a growing season, but seeds will allow a plant to grow new plants.
  • In addition to the end of the growing season, what other environmental challenges do your plants have to overcome?
    Student should recognize that they should keep track of rainy periods, when their plant roots can absorb more water. They also need to keep track of their resources. By this point, students should realize that adding roots and leaves increases their overall resource capacity.
  • What flowers have you played? Which ones are the most challenging? Why?
    Students should realize that flowers that are both male and female are more challenging. In addition, more advanced plants are more difficult to grow successfully but also buy you more seeds.
  • Ask students to create a list of strategies they have learned by playing the game.
    • The list should be written for a student just learning the game.
    • Tell students to be sure to suggest ways of maximizing seed production.
    Students should be aware that growing roots early in the game is important, because roots help you obtain two out of three resources. In addition, it is important to build ample resource capacity before fruiting and pollinating flowers.

Game Discusson

  • How was Strategy mode different from Classic mode? Was it more or less challenging? Why?
    Student answers will vary. However, some students will find the Classic mode more challenging, because in that mode, the student is playing against the clock. Whereas the Strategy mode allows the student to think through each answer before making a decision.
  • How did your plants in Reach for the Sun reproduce? Why was it important for the plants to reproduce during the growing season?
    Students should recognize that their sunflowers produced seeds. These seeds help ensure that the plant will be able to reproduce.
  • Did you learn any new strategies as you played the game this time? If so, what are they?
    Student answers will vary. However, students will probably find that playing in the Strategy mode helps them think through various options.

Hands-On Activities

Have students read the introduction in the Student Guide. As they are reading, distribute the materials for both hands-on activities.

Part 1: Observing Fruits

Explain to students that they will be observing fruits from different plants and looking closely at the seeds of each fruit. Engage students in a general discussion about the life cycles of flowering plants.What parts do fruits and seeds play in these life cycles?

Distribute or project the image below from the appendix on an interactive whiteboard. You may also want to have students refer to the Flower Dissection Data Chart from the Warm-Up Lesson.

Discuss the main life cycle stages of a flowering plant. Point out the different ways in which flowering plants are pollinated, and discuss the advantages and disadvantages of each.

In self-pollination, pollen is transferred from the male to the female reproductive structures within the same plant. In cross-pollination, which is more common, pollen is transferred from one plant to another. The need for only one flowering plant is an advantage of self-pollination, and a lack of trait variation is a disadvantage. The opposite is true of cross-pollination. An advantage is that it leads to more trait variation, which better enables plants to adapt to different environments. A disadvantage is the need for two parent plants, which causes a potential problem of transferring pollen from one plant to another.

Have students complete steps A through E in the Student Guide. Remind students not to eat the fruits! You may want to bring in extra fruits that have been cleaned and handled hygienically for students to sample.

After students are finished observing the fruits, instruct them to clean up their workspaces. Discuss students’ observations as a class:

Student Questions

  • Observe the peas. Which part is the fruit and which parts are the seeds? What is the function of the fruit?
    The pod is the fruit and the green peas are the seeds. The pod protects the seeds.)
  • Observe the strawberries. Where do you think the seeds are located?
    Most students will assume that the seeds are the specks on the outside of the strawberry. However, these specks are actually individual fruits, and each fruit has a tiny seed inside of it. The red part of the strawberry is actually accessory tissue formed from multiple ovaries of one flower!
  • Observe the tomatoes. The seeds are made from several fused carpals, which make up the pistil of a flower. Try to identify and count the carpals.
  • Observe the banana slices. Describe the seeds.
    Sample response: The seeds are tiny and black. There are a lot of them clustered in the center of the fruit.
  • Think about all four fruits that you observed. How were they different? How were they similar? What are some possible advantages that one kind of fruit might have over another in terms of reproductive success?
    Sample response: All of the fruits contained seeds, but the seeds were different sizes. The banana seeds were very small, but there were more of them in a single fruit than there were in the peas and tomatoes. This would be an advantage because more seeds would be likely to be dispersed and grow into adult plants.

Part 2: Germinating Seeds

Have students read the introduction in the Student Guide as you distribute or project the image below from the appendix onto an interactive whiteboard.

Briefly review the procedure, and then have students complete steps 1 through 3 with a partner. When they have finished sealing their baggies, students will need to tape them to a sunny window or wall with exposure to a light source.

Discuss students’ responses to the questions in steps 1 and 2 as a class.

Exit Slip

Have students complete the Exit Slip activity in the Student Guide and submit the activity before leaving the classroom. Review the student responses before the next lesson.