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Lesson 4 Summary
Use with pp. 164–167
Lesson 4: How do plants depend on
animals?
seed dispersal the process that scatters plant seeds to new places
You read in Lesson 2 that plants must be
pollinated for seeds to form. Pollen is made
in the flower’s male parts, called stamens.
Pistils are the flower’s female parts. In
pollination, the pollen needs to get from
the stamens to the pistils. Some plants need
help from animals to do this.
Flowers make a sweet liquid called
nectar. Nectar is a tasty food for some bats,
bees, butterflies, and birds. The animals eat
the nectar inside the flower. Pollen sticks to
the animals. Then the animals carry the
pollen to the next flower. The pollen may
stick to the pistils of the next flower. Bees
also carry pollen back to their hives.
From Fertilization to Food
What happens when pollen lands on a
pistil? A thin tube grows out of the pollen.
The pollen tube grows down through the
pistil. The pollen tube gets to egg cells
inside the pistil. Sperm cells from the pollen
move through the tube. The sperm cells
combine with the egg cells. This is called
fertilization.
After fertilization, the flower changes a
lot. The fertilized eggs become seeds.
The bottom part of the pistil grows into
a fruit. The fruit protects the seeds. Many
fruits, like apples and pumpkins, are good
for animals and people to eat.
Seeds on the Move
Seed dispersal means the many ways
that plants scatter their seeds, or send
their seeds to different places. Some plants
just drop their seeds on the ground. Some
plants spread seeds in the wind or in water.
But many plants need animals to help.
Fruits help plants spread their seeds far
away. For example, a bird may pick a berry
34 Chapter 5, Lesson 4 Summary
from a plant. Then the bird may fly to
another place, eat the fruit, and leave the
seed.
Some animals, like squirrels and mice,
bury seeds in the ground to eat later.
Sometimes these seeds sprout into plants
before the animal can eat them.
Sometimes an animal eats fruit and
swallows the seeds. The seeds are not
digested. They come out in the animal’s
wastes. Animals can carry seeds far from
the parent plant.
Seed Dispersal
Animals can carry seeds on their bodies.
Some seeds are inside prickly pods, or
shells, called burs. The burs have tiny
hooks that stick to an animal’s fur or hair.
The animal carries the bur away. When
the bur falls to the ground, the seeds inside
may grow into new plants.
Plants disperse seeds by wind and water
too. Wind carries the seeds of maple trees
and the seeds of dandelions. Coconut seeds
float in water. Ocean currents can carry
coconut seeds very far.
Plants need adaptations for seed
dispersal. Imagine that a cherry tree drops
all its seeds under the tree. Some new
trees or seedlings will grow, but they will
compete with the parent tree. The parent
tree gets most of the water and nutrients
from the soil. The parent tree’s leaves get
most of the sunlight. The seedlings will not
get what they need to grow. The seedlings
will have a better chance to grow if they
are far away from the parent plant.
Intervention Study Guide
© Pearson Education, Inc. 4
Pollen on the Move
Name ______________________________
Lesson 4 Questions
Use with pp. 164–167
Lesson 4 Questions
1. What must happen for seeds to form?
2. W
hat happens after a pollen tube grows down and gets to the egg cells
inside the pistil?
3. S ome plants need animals to help spread their seeds. For example, a
bird may pick a berry and help spread the berry seeds. What is one
other way an animal can carry seeds far away from the parent plant?
3. I magine that there are cherry seeds under a parent tree. The seeds
grow into new trees, or seedlings. Which gets most of the water,
nutrients, and sunlight? Circle the correct answer:
parent tree
© Pearson Education, Inc. 4
seedlings
Intervention Study Guide
Chapter 5, Lesson 4 Questions 35