1. Unit on Flowering Plants
Angiosperms
Unit on Flowering Plants

2. Objectives Learn the basic structures of a flower and their functions
Learn about the role flowers play in pollination and fertilization
Learn about the seeds and fruits of flowering plants

3. Flower Structure
On the right is a model of a flower and its different parts.
Learn the parts and their functions.
Click each question mark to look at the individual parts. Click picture on top to see more pictures of flowers.

4. Parts of a flower:
Petals- colorful part—(function: attracts pollinators)
Sepals- leaf-like structures that encircle the stem (function: protects)
Stamen- male part of flower
Pistil- female part of flower

5. Stamen The stamen is the male reproductive organ. Made of 2 parts:
Filament– holds anther into the air to help release pollen
Anther—produces the pollen (sperm)
Anthers
Filament
Explain that anther arrangement varies with each flower, and that pollen contains two types of cells: a tube cell and sperm cells. Talk about the two parts of the stamen: anther and filament. The tube cell leads to ovary and the sperm fertilize the ovule inside the ovary. The process will be shown later.

6. Pistil
The pistil is the female reproductive organ. It receives the pollen
Made of 4 parts:
Ovary- forms the egg
Stigma- where the pollen sticks
Style- provides tube down to ovary (pollen tube)
Ovule- in ovary-forms the seed
Explain the role of each part of the pistil, and the process of the sperm fertilizing the ovule, inside the ovary.

7. Two types of flowers:
1. complete flower– has male and female parts on the same flower
(has pistil and stamen)
2. incomplete flower– missing a male or female part
(ex. Squash have separate male and female flowers)

8. Pollination
Pollen
Pollination is the transfer of pollen from the anther to the stigma.
Why is there more pollen than eggs? Increases chances of fertilization occurring (not all pollen makes it to the egg)
Explain again that petals attract pollinators. Pollination may be carried out naturally or artificially. Talk about different ways.

9. How is pollen transferred?
1. wind or water
2. by insects/birds feeding on nectar
3. by pollinators attracted to bright colors or scent

10. Path of pollen cells through the pistil Tomato ovary with ovules
Fertilization
The process of the sperm of the pollen grain fertilizing the ovule inside the ovary.
Path of pollen cells through the pistil
Detail the pollen path and explain that after fertilization, the ovule becomes a seed. There is more on that later.
Tomato ovary with ovules

11. Steps of fertilization:
1. pollen is transferred to the stigma by wind/water or pollinators
2. Pollen goes down the pollen tube to the ovary (egg)
3. The sperm fertilizes the egg forming a fertilized egg called a endosperm
4. After fertilization, the sepals, petals, anthers and upper pistil fall off (wilt)
5. The wall of the ovary hardens to protect the embryo and a flesh develops around it to nourish it called a fruit

12. Tomato fruit with seeds
Formation of a seed
When the ovule is fertilized, it becomes a seed and is enclosed in a fruit.
Tell class that in many flowers there may be more than one ovule, like in the tomato fruit. The ovary begins to change to form into a fruit. Explain that a seed is an embryo of a future plant.
There are two types of embryos in angiosperms:
monocots and dicots
Tomato fruit with seeds

13. Peanuts and beans are dicots
Monocots
Dicots have two cotyledons present.
In monocots, there is only one cotyledon present.
Tell the definition of a cotyledon. Explain other ways you can tell if a plant is a monocot or dicot, such as: leaf pattern and number of petals present. Click bean pod to go back.
Peanuts and beans are dicots
Corn is a monocot

14. The End!
Give reading assignment for next unit.