The Characteristics of Seed Plants

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Table of Contents

• The Characteristics of Seed Plants
• Gymnosperms
• Angiosperms
• Plant Responses and Growth
• Feeding the World

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How Seeds Become New Plants
- The Characteristics of Seed Plants

• A seed has three main partsan embryo, stored
  food, and a seed coat. If a seed lands in an area
  where conditions are favorable, the plant sprouts
  out of the seed and begins to grow.

3
Root Structure
- The Characteristics of Seed Plants

• A roots structure is adapted for absorbing water
  and minerals from the soil.

4
Stems
- The Characteristics of Seed Plants

• Trees have woody stems. A typical woody stem is
  made up of many layers. The layers of xylem form
  annual rings that can reveal the age of the tree
  and the growing conditions it has experienced.

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Leaves
- The Characteristics of Seed Plants

• Leaves capture and use the suns energy to make
  food. The structure of a leaf is well-adapted for
  photosynthesis.

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Outlining
- The Characteristics of Seed Plants
The Characteristics of Seed Plants

• As you read, make an outline about seed plants
  that you can use for review. Use the red headings
  for the main ideas and the blue headings for the
  supporting ideas.

• What Is a Seed Plant?
• Vascular Tissue
• Seeds
• How Seeds Become New Plants
• Seed Structure
• Seed Dispersal
• Germination
• Roots
• Types of Roots
• The Structure of a Root
• Stems
• The Structure of a Stem
• Annual Rings
• Leaves
• The Structure of a Leaf
• The Leaf and Photosynthesis
• Controlling Water Loss

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More on Leaves
- The Characteristics of Seed Plants

• Click the PHSchool.com button for an activity
  about leaves.

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End of SectionThe Characteristics of Seed Plants
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Reproduction in Gymnosperms
- Gymnosperms

• First, pollen falls from a male cone onto a
  female cone. In time, a sperm cell and an egg
  cell join together in an ovule on the female
  cone. After fertilization occurs, the seed
  develops on the scale of the female cone.

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Previewing Visuals
- Gymnosperms

• Preview the diagram showing the life cycle of a
  gymnosperm. Then write two questions that you
  have about the diagram in a graphic organizer
  like the one below. As you read, answer your
  questions.

The Life Cycle of a Gymnosperm
Q. How does gymnosperm pollination occur?
A. Pollen is transferred from a male reproductive
structure to a female reproductive structure
wind often carries pollen from male to female
cones.
Q. How does gymnosperm fertilization occur?
A. Pollen collects in a sticky substance produced
by ovules. Female scales close to seal in pollen
and fertilization occurs.
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Links on Gymnosperms
- Gymnosperms

• Click the SciLinks button for links on
  gymnosperms.

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End of SectionGymnosperms
13
The Structure of Flowers
- Angiosperms

• Flowers come in all sorts of shapes, sizes, and
  colors. But, despite their differences, all
  flowers have the same functionreproduction.

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The Structure of a Flower Activity
- Angiosperms

• Click the Active Art button to open a browser
  window and access Active Art about the structure
  of a flower.

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Reproduction in Angiosperms
- Angiosperms

• First, pollen falls on a flowers stigma. In
  time, the sperm cell and egg cell join together
  in the flowers ovule. The zygote develops into
  the embryo part of the seed.

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Types of Angiosperms
- Angiosperms

• Angiosperms are divided into two major groups
  monocots and dicots.

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Multiples
- Angiosperms

• Is a flower with 6 petals a monocot? To answer
  this question you need to determine if 6 is a
  multiple of 3. A number is a multiple of 3 if
  there is a nonzero whole number that, when
  multiplied by 3, gives you that number. In this
  case, 6 is a multiple of 3 because you can
  multiply 2 (a nonzero whole number) by 3 to get
  6.
• 2 X 3 6
• Therefore, a flower with 6 petals is a monocot.
  Other multiples of 3 include 9 and 12.

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Multiples
- Angiosperms

• Practice Problem
• Which of these numbers are multiples of 4?
• 6, 10, 12, 16

• 12 and 16

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Building Vocabulary
- Angiosperms

• Using a word in a sentence helps you think about
  how best to explain the word. After you read the
  section, reread the paragraphs that contain
  definitions of Key Terms. Use all the information
  you have learned to write a meaningful sentence
  using each Key Term.

Key Terms
Examples
angiosperm
Refflesia belongs to the group of seed plants
known as angiosperms.
Monocots are angiosperms that have only one seed
leaf.
The stamens are the male reproductive parts.
The female parts, or pistils, are found in the
center of most flowers.
Dicots produce seeds with two seed leaves.
flower
A flower is the reproductive structure of an
angiosperm.
This hollow structure is the ovary, which
protects the seeds as they develop.
sepal
When a flower is still a bud, it is enclosed by
leaflike structures called sepals.
As the seed develops after fertilization, the
ovary changes into a fruita ripened ovary and
other structures that enclose one or more seeds.
petal
When the sepals fold back, they reveal the
flowers colorful, leaflike petals.
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End of SectionAngiosperms
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Seasonal Changes
- Plant Responses and Growth

• The amount of darkness a plant receives
  determines the time of flowering in many plants.

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Germination and Temperature
- Plant Responses and Growth

• One hundred radish seeds were planted in each of
  two identical trays of soil. One tray was kept at
  10ºC, and one tray was kept at 20ºC. The trays
  received equal amounts of water and sunlight. The
  graph shows how many seeds germinated over time
  at each temperature.

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Germination and Temperature
- Plant Responses and Growth

• Reading Graphs
• What variable is plotted on the horizontal axis?
  What variable is plotted on the vertical axis?

• Horizontal axisdays vertical axistotal number
  of germinated seeds

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Germination and Temperature
- Plant Responses and Growth

• Interpreting Data
• How did the number of seeds that germinated
  change between day 20 and day 25 at 10ºC? At 20ºC?

• The numbers did not change.

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Germination and Temperature
- Plant Responses and Growth

• Drawing Conclusions
• According to the graph, at which temperature did
  more seeds eventually germinate? What can you
  conclude about the relationship between
  temperature and germination?

• 20ºC the number of germinating seeds increases
  as the temperature increases.

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Germination and Temperature
- Plant Responses and Growth

• Predicting
• Predict what the graph would look like for a tray
  of radish seeds kept at 5ºC. Give a reason for
  your prediction.

• The slope would be less steep because fewer seeds
  would germinate.

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Relating Cause and Effect
- Plant Responses and Growth

• A cause makes something happen. An effect is what
  happens. As you read through the paragraphs under
  the heading Hormones and Tropisms," identify
  four effects of plant hormones. Write the
  information in a graphic organizer like the one
  below.

Effects
Tropisms
Germination
Cause
Forming flowers, stems, leaves
Plant hormones
Shredding leaves
Development and ripening of fruit
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Links on Plant Responses
- Plant Responses and Growth

• Click the SciLinks button for links on plant
  responses.

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End of SectionPlant Responses and Growth
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Identifying Main Ideas
- Feeding the World

• As you read, write the main idea in a graphic
  organizer like the one below. Then write three
  supporting details that give examples of the main
  idea.

Main Idea
Technologies that may help produce more food
include
Detail
Detail
Detail
Precision farming uses satellite images and
computer to determine the amount of water and
fertilizer needed.
Hydroponics plants are grown in solutions of
nutrients instead of soil.
Genetic engineering genetic material is altered
to produce plants with useful qualities.
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Links on Plants as Food
- Feeding the World

• Click the SciLinks button for links on plants as
  food.

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End of SectionFeeding the World
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Graphic Organizer
Seed plants
have
Roots
Stems
Leaves
capture
provide
absorb
are needed for
Water and minerals
Transport
Anchorage
Support
Sunlight
used in
Photo-synthesis
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End of SectionGraphic Organizer