Presentation for teaching angiosperm life cycles to middle schoolers

1. The Life Cycle Of
Flowering Plants

2. Flowering Plants (Angiosperms)
• Flowering plants, also called
angiosperms, are a category of
plants that produce or bear flowers.
Examples are beans, mango, most
grasses, maize, guava and hibiscus.
• Angiosperms, together with
gymnosperms, are seed-bearing
plants.
• Non-flowering plants are the other
category of plants which do no
produce or bear flowers. Examples
are cassava, potatoes, ferns, moss,
etc.
beans
mango
grass
maize
hibiscus
cassava
fern
moss

3. Stages in the Life Cycle of Flowering
Plants

4. Flowering
• This is the stage where a
flower develops from a
bud.
• In the bud stage, the
sepals cover the petals
and the flower is closed
and only opens up when it
is fully developed.

5. Flowers
A flower is the organ of a
plant that is responsible
for sexual reproduction.
Petals, which form the
corolla, are brightly colored,
and sweet-smelling to attract
insects, birds, and other
agents of pollination
Sepals, which form the calyx,
protect the rest of the flower
while it is still developing.
Anther
Filament
Stamen, the male
reproductive part
of a flower
Style Stigma
Ovary
Ovules
Carpel, the female
reproductive part of a
flower
Stalk

6. Pollination
Self-pollination: this occurs when pollen
grains are transferred from the anther
of a flower to the stigma of the same
flower or another flower of the same
plant.
• It is the transfer of pollen from the anther to the stigma of
a flower.
• Pollen grains are the male sex cells (gametes) in the flower,
and are produced in the stamen.
• The main agents of pollination are wind and small animals
and insects, such as bees, butterflies, humming birds, etc.
Cross-pollination: this occurs when pollen grains are
transferred from the anther of a flower to the stigma
of a flower on another plant of the same kind.

7. Fertilization
• This refers to the fusion of the
male and female gamete of a
plant to form a zygote.
• The male gametes of a flower
are the pollen grains, and the
female gametes are the ovules.
• When pollen lands on the stigma
of a flower, it grows a pollen
tube down the style and into the
ovary in order to reach the
ovules.
stigma
Pollen tube
anther
ovary
ovules

8. Fertilization and Fruit-Bearing
• After fertilization, the zygote(s)
(ovules + pollen) develops into the
seed(s) and the ovary develops into
a fruit (pericarp).
• The fruit has three main layers
which are epicarp/exocarp,
mesocarp and endocarp moving
from the surface towards the
interior.
• The seed is covered with a hard
coat called a testa, and has
cotyledon and/or endosperm to
store food for germination.

9. Dispersal of Fruits and Seeds
• This is the process by which fruits and
seeds are carried/scattered away
from the parent plant.
• Mechanisms of seed dispersal:
• Animal agents such as humans, birds and
monkeys. Examples of fruits that are
dispersed this way include mango,
berries, tomatoes, etc.
• Wind, e.g. for Tridax, dandelions, cotton,
etc.
• Water, e.g. for coconuts, red mangrove,
etc.
• Explosive mechanism, e.g. for okra
(okro), Pride of Barbados, soybean, etc.

10. Seed Germination
• Germination is the development
a new plant from a seed.
• The roots begin developing
before the shoot system.

11. Factors Necessary For Germination
• External
• Water
• Air
• Suitable temperature
• Internal
• Viability of seed
• Enzymes