Section Outline
Section 24-1
24–1
Reproduction With Cones and Flowers
A. Alternation of Generations
B. Life Cycle of Gymnosperms
1. Pollen Cones and Seed Cones
2. Pollination
3. Fertilization and Development
C. Structure of Flowers
1. Sepals and Petals
2. Stamens and Carpels
D. Life Cycle of Angiosperms
E. Pollination
F. Fertilization in Angiosperms
Go to
Section:
Compare/Contrast Table
Section 24-1
Comparing Wind-pollinated and Animal-pollinated Plants
Characteristics
Wind-pollinated
Plants
Animal-pollinated
Plants
Pollination method
Wind pollination
Vector pollination
Relative efficiency of
pollination method
Less efficient
More efficient
Plant types
Mostly gymnosperms and Angiosperms
some angiosperms
Reproductive organs
Cones
Flowers
Adaptations that
promote pollination
Pollination drop
Bright colors, sweet
nectar
Go to
Section:
Figure 24–1 Evolution of the Gametophyte
and the Sporophyte
Section 24-1
Gametophyte (N)
Sporophyte (2N)
Bryophytes
Go to
Section:
Ferns
Seed plants
Figure 24–4 The Life Cycle of a Gymnosperm
Section 24-1
Go to
Section:
Figure 24–5 The Structure of a Flower
Section 24-1
Stamen
Anther
Filament
Ovule
Go to
Section:
Stigma
Style
Carpel
Ovary
Petal
Sepal
Figure 24–7 The Life Cycle of an Angiosperm
Section 24-1
Pollen grains (N)
(male gametophyte)
Anther (2N)
Haploid (N)
Diploid (2N)
Stigma
Pollen
tubes
Style
MEIOSIS
Haploid cell
(N)
Ovary
Ovule
Embryo sac (N)
(female gametophyte)
Egg cell
Mature
sporophyte
Seedling (2N)
(new sporophyte)
Sperm
Pollen tube
Endosperm nuclei
Endosperm
(3N)
Embryo
(2N)
FERTILIZATION
Endosperm
Seed coat
Go to
Section:
Fruit
Zygote
(2N)
Interest Grabber
Section 24-2
From Fruits to Nuts
Walk into any supermarket and you will likely see a variety of fruits. Would
it surprise you to learn that many of the foods that you think of as
vegetables, grains, and nuts are actually fruits?
1. Name three fruits that you have eaten.
2. Describe any seeds you found in the fruits.
3. What function do you think the fruit and seeds serve for a plant?
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Section:
Section Outline
Section 24-2
24–2
Seed Development and Germination
A. Seed and Fruit Development
B. Seed Dispersal
1. Dispersal by Animals
2. Dispersal by Wind and Water
C. Seed Dormancy
D. Seed Germination
Go to
Section:
Concept Map
Section 24-2
Seed
Germination
in
Monocots
Dicots
have
have
1 Cotyledon
2 Cotyledons
that
that
Remains with
the seed
Go to
Section:
Emerge
above ground
Remain
below ground
Interest Grabber
Section 24-3
Rooting for a Plant
People who have gardens or houseplants often grow extra plants by
making cuttings—leafy stem pieces or small sprigs of plants—that are then
partially buried in soil or in a special rooting mixture to “root.” In this
process, the cut stems develop roots. When the roots are large enough,
the cutting is potted or put into the ground, where it grows into a complete
plant. This process works well with many plants, including begonias,
geraniums, coleus, African violets, forsythia, and willow.
Go to
Section:
Interest Grabber continued
Section 24-3
1. For a gardener, what might be an advantage of growing plants from
cuttings rather than from seeds?
2. Herbaceous plants, such as coleus, root faster than do woody plants, such
as willow. How would you explain this difference?
3. How would plants grown from cuttings compare to the plant from which the
cuttings were taken? Why would this be an advantage for a gardener?
Go to
Section:
Section Outline
Section 24-3
24–3
Plant Propagation and Agriculture
A. Vegetative Reproduction
B. Plant Propagation
1. Cuttings
2. Grafting and Budding
C. Agriculture
1. Worldwide Patterns of Agriculture
2. Changes in Agriculture
Go to
Section:
Compare/Contrast Table
Section 24-3
Comparing Plant Propagation Methods
Method
Procedure
Cuttings
A length of stem that includes lateral buds is cut from
the parent plant and partially buried in soil or rooting
mixture to take root.
Grafting
A piece of stem is cut from the parent plant and
attached to another plant.
Budding
A piece of lateral bud is cut from the parent plant and
attached to another plant.
Go to
Section:
Video
Life Cycle of Angiosperms
QuickTime™ and a
decompressor
are needed to see this picture.
Click the image to play the video segment.
Go Online
Links from the authors on genetically designing flowers
Interactive test
Articles on agriculture
For links on seed structure and function, go to www.SciLinks.org and
enter the Web Code as follows: cbn-7242.
Interest Grabber Answers
1. What are some ways in which male reproductive cells in pollen might reach
female reproductive cells?
Possible answers: pollen is carried on the wind, by animals, or by
moving water.
2. How does the pollen adhere to the female reproductive structure?
The top of the female reproductive structure (stigma) is sticky.
3. Many people experience allergic reactions when pollen grains enter
their respiratory systems. How do you think the pollen reached their bodies?
Pollen is carried on the wind; when people inhale, they take in the pollen.
People can also get pollen into their bodies by touching first a plant and then
their faces.
4. How might people who are allergic to pollen reduce their exposure to it?
Students may suggest that people wash their hands after handling plants or
stay indoors when the pollen count is high.
Interest Grabber Answers
1. Name three fruits that you have eaten.
Possible answers: apples, strawberries, grapefruit, oranges
2. Describe any seeds you found in the fruits.
Small seeds in the apple core, tiny seeds on the outside of berries, large
seeds within grapefruit sections, smaller seeds within orange sections
3. What function do you think the fruit and seeds serve for a plant?
Fruit attracts animals that spread seeds; seeds allow new plants to grow.
Interest Grabber Answers
1. For a gardener, what might be an advantage of growing plants from
cuttings rather than from seeds?
Growing plants from cuttings is faster than growing them from seeds. Also,
there is no need to shop for seeds.
2. Herbaceous plants, such as coleus, root faster than do woody plants, such
as willow. How would you explain this difference?
Woody plants grow slowly, so it makes sense that they would develop roots
slowly, too.
3. How would plants grown from cuttings compare to the plant from which the
cuttings were taken? Why would this be an advantage for a gardener?
They would be just like the original plant. This is an advantage if the
gardener wants many identical plants.
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