Transcript Unit 4 Lesson 3 How Do Plants Grow and Reproduce? Nonvascular plants Vascular plants Spore Gymnosperm Angiosperm Germinate Copyright © Houghton Mifflin Harcourt Publishing Company.

Unit 4 Lesson 3 How Do Plants Grow and Reproduce?
Nonvascular plants
Vascular plants
Spore
Gymnosperm
Angiosperm
Germinate
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Unit 4 Lesson 3 How Do Plants Grow and Reproduce?
Tubes for Transport
• Nonvascular plants are
simple plants that lack vascular
tissue, which easily transports
water from the ground into the
plant.
• They grow in damp places and
almost never grow taller than
10 cm.
• Nonvascular plants move
materials by absorbing
nutrients and water in the same
way that a sponge absorbs
water.
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Unit 4 Lesson 3 How Do Plants Grow and Reproduce?
Tubes for Transport
• Vascular plants have vascular
tissues that allow them to move
water, nutrients, and sugars
across long distances.
• Vascular tissue contains tiny
tubes, which move water and
nutrients up a plant in the same
way that water moves up a
straw.
• Most plants, including trees,
grasses, and shrubs, are
vascular plants.
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Unit 4 Lesson 3 How Do Plants Grow and Reproduce?
Tubes for Transport
• Vascular plants have
true leaves and roots.
• Vascular tissue includes
two kinds of smaller
tubes. Xylem carries
water and nutrients
from the roots to the
other parts of the plant.
• Phloem carries sugar
from the leaves to the
rest of the plant.
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Unit 4 Lesson 3 How Do Plants Grow and Reproduce?
No Seeds, Please!
• A spore is a single reproductive cell that can grow into a
new plant.
• Both nonvascular plants, such as mosses and liverworts,
and vascular plants, such as ferns, use spores to
reproduce.
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Unit 4 Lesson 3 How Do Plants Grow and Reproduce?
No Seeds, Please!
• All of these plants have
a sexual generation and
an asexual generation in
their life cycles.
• For example, the sexual
generation of moss has
male parts producing
sperm and female parts
producing eggs. When
sperm and egg
combine, the fertilized
egg grows into a stalk.
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Unit 4 Lesson 3 How Do Plants Grow and Reproduce?
No Seeds, Please!
• The stalk is the asexual generation of
moss. A capsule grows at the end of
the stalk, forming spores that shoot
out when the capsule opens.
• These spores land on the ground and
develop into threadlike plants that
form buds, which turn into green
“leafy” structures.
• The “leafy” sexual generation of
moss, the most familiar form of the
plant, makes food and root-like
structures that anchor the plants to
the ground.
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Unit 4 Lesson 3 How Do Plants Grow and Reproduce?
No Seeds, Please!
• Like mosses, ferns also use
spores to reproduce. In ferns, the
reproductive spores form inside
clusters on the underside of the
leaflets.
• The spores are released and fall
to the ground when the pockets
burst.
• The spores then grow into a tiny
fern plant. This structure releases
sperm and egg cells that, once
fertilized, grow into a young fern.
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Unit 4 Lesson 3 How Do Plants Grow and Reproduce?
No Seeds, Please!
• The young fern grows
into the large, upright
fern plant, called the
frond. This is the
asexual generation of
the fern.
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Unit 4 Lesson 3 How Do Plants Grow and Reproduce?
Seed Power!
• While spores need to stay moist and
sprout soon after release, seeds have
a covering that protects them until
conditions are right for sprouting.
• Gymnosperms are plants that do
not produce seeds in flowers.
Gymnosperm seeds have a
protective seed coat, but are not
enclosed by fruit.
• Cone-producing plants, called
conifers, are the most common
gymnosperms. Conifers include pine,
fir, spruce, and cedar trees.
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Unit 4 Lesson 3 How Do Plants Grow and Reproduce?
Seed Power!
• Angiosperms are plants that produce seeds in flowers.
• Since angiosperm seeds are often enclosed in fruit, they
are easily spread when animals eat the fruits.
• Gymnosperm seeds may also be spread by animals, but
typically fall to the ground and grow where they land.
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Unit 4 Lesson 3 How Do Plants Grow and Reproduce?
From Flower to Fruit to Seed
• Typical flowers have
both male and
female reproductive
parts.
• A male part, the
anther, produces
pollen, or the
sperm.
• The female parts
include the stigma
and the ovary, which
contains eggs in
ovules.
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Unit 4 Lesson 3 How Do Plants Grow and Reproduce?
From Flower to Fruit to Seed
• Flowers produce nectar that
organisms may eat. When an
organism gathers nectar, pollen
may brush onto it.
• The organism carries this
pollen when it moves to the
next flower. This process is
called pollination.
• When the pollen reaches the
stigma, it travels down to the
ovary and fertilizes the ovules.
This process is called
fertilization.
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Unit 4 Lesson 3 How Do Plants Grow and Reproduce?
From Flower to Fruit to Seed
• Fertilized ovules
develop into seeds,
and the ovule wall
becomes a seed coat.
The ovary that holds
the seeds develops into
the fruit, such as a
pumpkin.
• The development of a
pumpkin seed into a
mature pumpkin fruit
follows a sequence of
events.
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Unit 4 Lesson 3 How Do Plants Grow and Reproduce?
From Flower to Fruit to Seed
• Pollen enters the
flower’s ovary and
fertilizes the ovules.
The ovary grows and
the petals fall off. The
ovules develop into
seeds inside the ovary.
• Finally, the outer layer
of the ovary thickens to
form a fruit around the
seeds. The mature
pumpkin is filled with
seeds.
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Unit 4 Lesson 3 How Do Plants Grow and Reproduce?
From Flower to Fruit to Seed
• Identify the following parts of a flower: anther,
ovary, ovules, petals, stigma.
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Unit 4 Lesson 3 How Do Plants Grow and Reproduce?
How Seeds Grow
• Seeds have a hard outer coat that
protects them and allows them to rest
until the environment is right for
growing.
• Many plant seeds rest during winter
and then germinate, or start to grow,
when the ground becomes warm and
moist in the spring.
• A dormant seed lies in the soil until
conditions are right for growing. The
seed germinates by absorbing water
and breaking through the seed coat.
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Unit 4 Lesson 3 How Do Plants Grow and Reproduce?
How Seeds Grow
• The embryo continues to grow and
a stem pushes upward.
Cotyledons provide energy for
growth and roots form and begin
growing downward.
• Leaves mature and the plant
starts absorbing more energy
from sunlight. It continues to grow
as the shoot pushes upward.
• The plant grows and matures until
it produces flowers and fruit.
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