Interest Grabber

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Interest Grabber
Interest Grabber
Section 24-1

• The Problem With Pollen
• Have you ever touched part of a flower and found
  a powdery, colored substance sticking to your
  fingers? That substance is pollen, which contains
  male reproductive cells. For reproduction to
  occur, tiny pollen grains must reach female
  reproductive cells, which are sometimes located
  on separate flowers.

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Interest Grabber continued
Interest Grabber
Section 24-1

• 1. What are some ways in which male reproductive
  cells in pollen might reach female reproductive
  cells?
• 2. How does the pollen adhere to the female
  reproductive structure?
• 3. Many people experience allergic reactions when
  pollen grains entertheir respiratory systems.
  How do you think the pollen reached their bodies?
• 4. How might people who are allergic to pollen
  reduce their exposure to it?

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Section Outline
Section 24-1

• 241 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

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Compare/Contrast Table
Section 24-1
Comparing Wind-pollinated and Animal-pollinated
Plants
Characteristics Pollination method Relative
efficiency of pollination method Plant
types Reproductive organs Adaptations that
promote pollination
Wind-pollinatedPlants Wind pollination Less
efficient Mostly gymnosperms and some
angiosperms Cones Pollination drop
Animal-pollinated Plants Vector pollination More
efficient Angiosperms Flowers Bright colors,
sweet nectar
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Figure 241 Evolution of the Gametophyte and the
Sporophyte
Section 24-1
Gametophyte (N) Sporophyte (2N)
Bryophytes
Ferns
Seed plants
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Figure 244 The Life Cycle of a Gymnosperm
Section 24-1
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Figure 245 The Structure of a Flower
Section 24-1
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Figure 247 The Life Cycle of an Angiosperm
Section 24-1
Haploid (N) Diploid (2N)
MEIOSIS
Ovule
FERTILIZATION
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Video
Video
Life Cycle of Angiosperms
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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 Outline
Section 24-2

• 242 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

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Concept Map
Section 24-2
SeedGermination
in
have
have
that
that
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Interest Grabber
Section 24-3

• Rooting for a Plant
• People who have gardens or houseplants often grow
  extra plants by making cuttingsleafy stem pieces
  or small sprigs of plantsthat 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.

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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?

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Section Outline
Section 24-3

• 243 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

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Compare/Contrast Table
Section 24-3
Comparing Plant Propagation Methods
Method Procedure
Cuttings
Grafting
Budding
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Internet
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.

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Section 1 Answers
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 entertheir 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.

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Section 2 Answers
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.

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Section 3 Answers
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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