Term 1 Topic 3 Sexual Reproduction in Angiosperms

• Seeds are produced in flowers, which are the sexual organs of Angiosperms.
• The components of a flower usually include:
  • male structures called stamens for producing pollen (containing male sex cells)
  • female structures called stigma (for receiving pollen), style and ovary (for producing female sex cells)
  • petals (for attracting pollinators)
  • sepals (for protecting the flower bud)
• Pollination and fertilisation are essential processes for flowers to produce seeds.
• Pollination is the transfer of pollen between plants of the same species for the purpose of fertilisation.
• Wind and water can facilitate pollination.
• Pollination can also be aided by pollinators such as insects, birds, mammals, etc.
• Flowers have special adaptations to promote pollination, such as large colourful petals, scent and sweet nectar to attract insects and birds.
• Pollinators play an important role in the production of food crops (such as maize) for humans.
• Fertilisation is the fusion of the male and female sex cells to produce seeds
• During fertilization the following happens: each mature pollen grain contains two male sex cells. When the pollen attaches to the stigma of a flower from the same species, the pollen produces a pollen tube, which grows down the neck of the:
• style, transporting the male sex cells to the ovule. Within the embryo sac of the ovule, one male sex cell fertilizes the egg, which develops into a seed.
• The other male sex cell unites with two cells in the embryo sac and this results in the development of the:
• endosperm, the starchy food that feeds the developing seed.
• The ovary enlarges and becomes a fruit.
• The seeds are contained in fruit .
• Fruits and seeds are dispersed in various ways.

• Greet the learners.
• Ask them if they can remember what flowering plants are called.

Answer:  Angiosperms

• What else can they remember about Angiosperms? You can refer back to Presentation 5, which included the following facts:
• it is the most diverse of plant groups.
• it is the largest group in the plant kingdom.
• all angiosperms use flowers for reproduction.
• seeds grow inside the flower after fertilisation.
• Tell learners that they are going to learn how these flowering plants reproduce.
• Show and explain PRESENTATION 1: Sexual Reproduction.

• Prepare for this activity by either collecting large flowers like hibiscus flowers or ask the learners to bring a flower.
• Ideally have one flower between 2 learners. Each group must have a scalpel joined to a scalpel handle.  If these are unavailable, use small, sharp knives.
• The learners will need to follow the instructions in WORKSHEET A very carefully, especially if they are using the scalpels as they are very sharp.
• Note that there is no memorandum for this worksheet. Learners’ sketches are to be compared with the sample sketch in the worksheet.

• Show VIDEO CLIP 1: Sexual reproduction in flowering plants (7:56 min.)
• Hand out FACT SHEET 1: Male and female reproductive parts of flowering plants.

• Hand out WORKSHEET B: Parts of a Flower for learners to complete.
• Ensure that they record the correct answers after they have reviewed the activity.
• Use the corresponding memorandum to assess this worksheet.

• Learners may complete the fun activity in WORKSHEET C in class or it can be given as homework.
• Use the corresponding memorandum to assess this worksheet.

• Show and explain PRESENTATION 2: Sexual Reproduction: 
• Explain to learners that they must watch and listen carefully, as they will be completing a worksheet on this presentation. Hand out WORKSHEET D: 
• Use the corresponding memorandum to assess this worksheet.

• Afford learners the opportunity to look at relevant slides again as they complete WORKSHEET D. Compare answers with the memorandum.

• Show VIDEO CLIP 2: Pollination for Kids (2:08 min.) 
• Show and explain PRESENTATION 3: Sexual Reproduction: 
• Show VIDEO CLIP 3: Time lapse video of a dandelion flower to seed head. This video was filmed continuously over a period of one month. (1:4 min.). 
• Show VIDEO CLIP 4:  Flower Reproduction (2:1 min.) 

• Hand out WORKSHEET E: Fertilisation in an Angiosperm for learners to complete. 
• Learners do not need to know the sketch.
• Use the corresponding memorandum to assess this worksheet.

• Show and explain PRESENTATION 4: Sexual Reproduction:  Seed Dispersal.
• Show VIDEO CLIP 5: Seed Dispersal (7:03 min.).

The video shows how seeds are scattered to different and suitable places where their growth is possible.

• Hand out WORKSHEET F: Seed dispersal.   
• Use the corresponding memorandum to assess this worksheet.

• If time allows, show VIDEO CLIP 6: Reproduction in Angiosperms (6:38 min.) to consolidate information.