Plant
Reproduction
Plants can reproduce Sexually and Asexually.
• Asexually- Plants can be regrown using a piece
of an old plant.
• Sexually- Most plants reproduce sexually using
spores or seeds.
2 Types of Reproduction
Asexual Reproduction
Sexual Reproduction
• New organism is produced • New organism is
produced from 2
from 1 parent’s genetic
parents’ genetic
material
material
• Limits diversity -offspring
and parent have the same • Genetic diversityoffspring and parents do
DNA.
not have the same DNA.
• Mostly unicellular
organisms.
• Mostly multicellular
organisms
Sexual Reproduction involves two processes:
• Meiosis
• Fertilization
A special form of cell
division that produces
sperm cells in males
and eggs in females.
Process that happens
when one male and one
female reproductive cell
combine to make a new
cell that can develop
into a new organism
Sexual Reproduction
Sperm carries ½ the
genetic material
Egg carries ½ genetic
material
They meet to form one
cell with a full set of
genetic material
Seeds vs. Spores
Seed is a young plant
that is enclosed in a
protective coating
Embryo
Stored Food
Protective Cover
Spore is a single
reproductive cell that can
grow into a new
organism.
Seeds vs. Spores
Spores and Seeds have common
characteristics.
• Have protective covering
• Can survive harsh dry, harsh conditions
• Contain parent plant’s genetic material
• Grows into a new plant
Seeds vs. Spores
Seeds
• Have multi-cellular embryo
inside
Spores
• Made up of a single cell
• Contain nutrient supply
• Do not contain nutrient
supply
• Spread by wind, water, and
animals
• Limited spreading mostly by
wind
• Sperm do not need water to
fertilize the egg.
• Sperm need to swim
through water to fertilize
the egg
“The Great Escape”: Germination
When a seed or
spore begins to
grow.
4 Groups of Plants
• Moss- Non-vascular plants that reproduce
with spores
• Ferns- Vascular plants that reproduce with
spores
• Gymnosperms- Vascular plants that reproduce
with “naked” seeds that are in cones.
• Angiosperms- Vascular plants that reproduce
with seeds in flowers and fruit.
Moss
Fern
Gymnosperms
• Plants that reproduce using
seeds but are not enclosed in
fruit.
• “Naked Seeds”
Conifers
Male Cone
Female Cone
Douglas Fir
Angiosperm
• A plant that has seeds that
produce flowers and fruit.
• Most species living now are
angiosperms.
Flower
• Reproductive structure of
an angiosperm
• Egg cells develop in the
ovary
• Pollen containing sperm
cells is located on the
anther.
• Pollen travels from anthers
to fertilize the flower.
Fruit
• The ripened, enlarged ovary
of a flower, which contains
seeds.
• When egg cells are fertilized
by pollen in the ovary the
ovary thickens and becomes
a fruit.
• Fruit can fall to the ground
or be eaten by animals
• If seeds inside the fruit land
in a place where they can
germinate they form a new
plant.
Flower
Ovary
Ovary
Seeds
Fruit
1
12
10
11
2
9
3
4
7
6
5
8
Life Cycle of a Cherry Tree
Meiosis
Fruit can be
eaten, or can
fall to the
ground.
Seeds and Fruit
Pollination
Fertilization
Life Cycle of a Conifer
1. Meiosis – pollen and eggs are made in cones
2. Pollination- pollen is released from male cones and gets
stuck to female cones
3. Fertilization- pollen “digs” a pollen tube that eventually
reaches the egg and sperm unite with egg.
4. Seed- a fertilized egg becomes an embryo; seeds will
disperse via wind, water, or animals.
5. Germination- seed lands and when conditions are right
begins to grow a new plant.
Gymnosperm
Both Gymnosperms
and
Plant with “naked seed
Angiosperms
Both have 2-stage life cycle
within a single plant
Angiosperm
Plant with seeds with flowers
or fruit
Separate male and female
structures
Reproduce sexually.
Some flowering plants can
reproduce asexually too.
If Rick planted 7 pots with seeds and got the
results below….
How many pots had seeds germinated?
4
What is so distinctive about
gymnosperm seeds?
Gymnosperms are “naked seeds”.
They have contain no fruit.
What do pollen grains and cone
scales contain?
Pollen grains contain sperm cells, and
female cone scales contain egg cells.
How does the shape of a pine seed
affect how it travels?
The shape of the seed allows the wind
to carry the seed away instead of falling
under the tree.
What advantage(s) do
gymnosperms have over mosses
and ferns?
Gymnosperms reproduce with seeds so
their seeds can provide nutrients to the
developing plant. Seeds can be spread
easier (wind, water, and animals).
Gymnosperms produce a lot of pollen, and
most of it blows away, never fertilizing an
egg. Why might this characteristic help a
plant species survive?
Lots of pollen increases the chances of a
pollen grain reaching the female cone and
the egg of another plant.
Since there is less surface area on the
needles of conifers for photosynthesis to
take place, How do you think these
plants get energy and materials they
need?
While they have smaller surface area to do
photosynthesis… conifers keep their leaves all year
round, so they can get energy and materials throughout
the year.
How do flowers relate to fruit?
Ovary of a flower becomes fruit.
How are animals involved in the life
cycle of some angiosperms?
Animals can be pollinators, carry
pollen from flower to flower.
Animals can disperse seeds through
eating the fruit then depositing seeds
in their waste.
What part of a flower later becomes a
fruit?
An ovary becomes a fruit.
What did the ovary contain in the
flower, and what does it contain as it
becomes a fruit?
In a flower the ovary contains eggs
which are fertilized by sperm in the
pollen. As the ovary develops
fertilized eggs become the seeds in
the fruit.