seed dispersal

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Transcript seed dispersal

How are new plants formed?
• from seeds
(sexual reproduction)
• by producing things such as
bulbs or tubers
(asexual reproduction).
Structure of a flowering plant
There are four main organs of a
flowering plant :
• The flower - contains the
reproductive organs.
• The leaves — these use light
energy, carbon dioxide and water
to make food by photosynthesis.
• The stem — this provides support and
a transport system for water and
minerals to the leaves and flowers and
to transport food from the leaves to
the roots.
• The roots — these anchor the plant to
the ground and absorb water and
minerals.
The Parts of a Flower
• Most flowers
have four parts:
• sepals,
• petals,
• stamens,
• carpels.
The parts of a flower
Stamens make pollen.
Petals attract insects.
Pistil is the
female organ
Sepals protect
the bud until it
opens.
Stamen (male)
• Anther: pollen grains
grow in the anther.
When the grains are fully
grown, the anther
splits open.
stamens
POLLEN
Pistil (female)
•
•
•
•
Stigma
Style
Carpel (ovary
Ovules (eggs)
stamens
pistil
Checkpoint
12
Cross pollination pollination is
transferred from
the male part
of one plant to the
female
part of another
plant.
Self pollination pollen is
transferred from
the male part
of a plant to the
female part
of the same
plant.
BAT POLLINATION
BIRD
POLLINATORS
Wind Pollination
These plants typically
do NOT have brightly
colored flowers.
Examples include
trees and grasses.
Wind Pollination
Pollination
Regardless of the type, the process is the
same.
The pollen settles on the stigma, and a
pollen tube grows to the ovary.
DOUBLE FERTILIZATION
(within the ovule)
One sperm
joins with
one egg to
form an
embryo
plant.
One sperm joins
with two polar
cells to become
endosperm
(stored food).
Fruit
The ovule turns into
the seed and the ovary
develops into a fruit.
AFTER FERTILIZATION
ovule
seed
ovary
fruit
The Seed
epicotyl
hypocotyl
micropyle
seed
coat
cotyledon
Fruits contain seeds and help
to disperse seeds.
SEED DISPERSAL
dispersal by
animals
eaten
buried
stick to fur
or clothing
WIND
DISPERSAL
WATER DISPERSAL
MECHANICAL
DISPERSAL