Download Living Things - Somerset Area School District

Seed Plants
Table of Contents
The Characteristics of Seed Plants
Gymnosperms
Angiosperms
Plant Responses and Growth
Feeding the World
Seed Plants
Characteristics of Seed Plants
-There are 250,000 species of seed producing
plants.
-All are vascular—this means they have
vascular tissue for growth and for transporting
food and water.
-Three types of vascular tissue:
*Xylem —transports water and minerals
*Phloem—transports food
*Cambium—makes new xylem and phloem
Seed Plants
Seeds and Pollen
-Seed producing plants do NOT have to
rely on water for reproduction.
-They produce sperm cells inside pollen
grains.
-The pollen grains deliver the sperm cells
to the egg cells to form the seed.
-A seed is a structure that contains a
young plant inside a protective covering.
Seed Plants
Seed Plants
How Seeds Become New Plants
A seed has three main parts–an embryo
(young plant), stored food (cotyledon),
and a seed coat (protective covering).
If a seed lands in an area where
conditions are favorable, the plant sprouts
out of the seed and begins to grow.
Seed Plants - The Characteristics of Seed Plants
How Seeds Become New Plants
Seed Plants
Seed Dispersal
-Seeds can be dispersed (spread out through
the environment) in many ways:
*Wind
*Water
*Attaching to animals or clothing
*Being eaten by animals and then released
in a new environment with the animal’s
feces.
*Jet propulsion
Seed Plants
Germination
-Germination is when the seed begins to
grow into a new plant.
-Many stay dormant until conditions are right
(sometimes hundreds of years).
-Seeds need proper water, oxygen, and
temperature to germinate. Some need
sunlight; some need darkness. They use up
their stored food as they grow.
Seed Plants
Plant Organs
-Plants, like animals, have specialized
organs for carrying out specific jobs.
-Plants have three main types of organs:
*Roots
*Stems
*Leaves
Seed Plants
Roots
-Roots take in water and minerals;
anchor plants in soil; store food; prevent
soil erosion.
-Two types of root systems:
Seed Plants
Roots
*Tap roots —main root is larger
than the other branching roots.
Ex: carrots, radishes, most
trees
*Fibrous roots –many thin
roots with other small roots
branching out.
Ex: grasses and corn
Seed Plants - The Characteristics of Seed Plants
Root Structure
-A root’s structure is
adapted for
absorbing water and
minerals from the
soil.
Seed Plants
Stems
-Stems function to support leaves and
flowers; transport food and water; some
store food (underground , like potatoes
and onions or above ground, like
sugarcane); some make food through
photosynthesis (like cacti).
Seed Plants
-Types:
*Herbaceous —soft and
green (tulip)
*Woody —hard and bark
covered (tree trunk)
Seed Plants - The Characteristics of Seed Plants
Stems
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.
Seed Plants
Leaves
-Leaves trap sunlight and make food through
photosynthesis.
-Parts of a leaf:
*Blade: large, flat part of leaf. It is usually
the greenest part and has chlorophyll for
making food.
*Petiole: thin stalk that connects the blade
of the leaf to the plant’s stem.
Seed Plants
Blade
Petiole
Seed Plants
* Cuticle—waxy waterproof coating
controls water loss
*Epidermis—(surface cells) thin, outer
layer of cells on top and bottom of the
leaf.
*Palisade layer—(upper leaf cells)
tightly packed cells trap the energy in
sunlight and carry out photosynthesis.
Seed Plants
*Spongy layer—(lower leaf cells)—widely
spaced cells allow carbon dioxide to
reach cells for photosynthesis and
oxygen to escape into the air.
*Veins—bundles of xylem and phloem
running through the leaf to carry water
and food.
*Stomata—tiny pores that allow carbon
dioxide to enter the leaf and oxygen and
water vapor to move out.
Seed Plants - The Characteristics of Seed Plants
Leaves
-The many layers of tissues
and cells in a leaf make its
structure well-adapted for
photosynthesis.
Epidermis
Chloroplasts
Vein
Xylem
Phloem
Cuticle
Palisade Layer
Spongy layer
Stomata
Seed Plants
Controlling Water Loss
-Transpiration is the process by which
water evaporates from a plant’s leaves.
-The stomata of the leaf controls the rate
of transpiration.
-The stomata can open and close to
control how fast water is lost.
Seed Plants - The Characteristics of Seed Plants
More on Leaves
Click the PHSchool.com button for an activity about leaves.
Seed Plants
End of Section:
The
Characteristics of
Seed Plants
Seed Plants
Types of Seed Plants
-There are two basic types of seed plants:
Angiosperms
Gymnosperms
Seed Plants
Gymnosperms
-Gymnosperms—vascular plants that
produce seeds inside cones.
*Seeds are not protected by a fruit
they are formed in cones; they
later fall out of these cones.
*Leaves are needle-like or
scale-like.
*Most are evergreens; keep their
leaves all year.
Seed Plants
Four Divisions of Gymnosperms
-Division Ginkgophyta —ginkgos:
deciduous gymnosperms with fan-shaped
leaves.
Example: Maidenhair Ginkgo Tree
Seed Plants
-Division Cycadophyta —Cycads:
palm-like gymnosperms.
Example: Florida Cycad
Seed Plants
-Division
Coniferophyta
conifers: most are
evergreens with
needle-like or
scale-like leaves
and pinecones.
Examples: pines,
firs, spruces,
cedars, junipers
Seed Plants
-Division Gnetophyta —Gnetum:
most are shrubs or woody vines.
found in the deserts of Asia, Africa
and S. America.
Example: Welwitchia
Seed Plants
Reproduction in Gymnosperms
-Most produce both male and female cones.
Female cones are large
with many woody
scales. Ovules form in
each scale and produce
egg cells
Male cones are small.
They produce pollen
grains containing
sperm cells.
Seed Plants
-Wind carries pollen grains from male to
female cones. (Pollination)
-A pollen tube grows from the pollen grain
to the ovule. Sperm cells swim down the
tube and fertilize the egg. A seed forms.
(Fertilization)
-Female cones mature and open,
releasing their seeds during fall or winter.
Seed Plants
-Seeds that fall may be carried away,
eaten or buried. (Dispersal)
-When conditions are right, some seeds
grow into new pine trees. (Germination)
Seed Plants - Gymnosperms
Reproduction in Gymnosperms
Seed Plants
Importance of Gymnosperms
-Gymnosperms have many important
commercial uses such as :
*Lumber
*Paper
*Soap, paint, varnish and some
medicines all made from tree sap
Seed Plants - Gymnosperms
Previewing Visuals
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.
Seed Plants - Gymnosperms
Links on Gymnosperms
Click the SciLinks button for links on gymnosperms.
Seed Plants
End of Section:
Gymnosperms
Seed Plants
Angiosperms
-Angiosperms—vascular plants that
produce seeds inside fruits.
*More than ½ of all plant species
are angiosperms.
*Angiosperm means “covered
seed”.
*All produce flowers and fruits.
*All belong to the Division Anthophyta.
Seed Plants - Angiosperms
The Structure of Flowers
Flowers come in all sorts of shapes, sizes, and colors. All
have the same function–reproduction.
Pistil
(female)
Anther
Stamen
Filament
(male)
Sepals
Stigma
Style
Ovary
Petal
Seed Plants - Angiosperms
The Structure of a Flower Activity
Click the Active Art button to open a browser window and
access Active Art about the structure of a flower.
Seed Plants
Reproduction in Angiosperms
-Pollen grains containing sperm cells are carried
from stamens to stigma (Pollination).
-A pollen tube grows from the pollen grain
to the ovule. Sperm swim down the pollen
tube and fertilize the egg cells.
(Fertilization).
-Ovules develop into seeds and the ovary
becomes the fruit.
Seed Plants - Angiosperms
Reproduction in Angiosperms
Seed Plants - Angiosperms
Types of Angiosperms
Angiosperms are divided into two major groups:
monocots and dicots.
Seed Plants - Angiosperms
Multiples
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.
2X3=6
Therefore, a flower with 6 petals is a monocot. Other
multiples of 3 include 9 and 12.
Seed Plants - Angiosperms
Multiples
Practice Problem
Which of these numbers are multiples of 4?
6, 10, 12, 16
12 and 16
Seed Plants
Importance of Angiosperms
-Angiosperms are an important source of
food for all life.
-All of our fruits and vegetables are
angiosperms.
-Angiosperms stabilize the atmosphere by
taking in huge amounts of carbon dioxide
for photosynthesis and releasing oxygen.
-Other uses: clothing, medicines, rubber,
oils, perfume, and pesticides.
Seed Plants - Angiosperms
Building Vocabulary
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:
monocot
angiosperm
stamen
pistil
dicot
flower
ovary
sepal
fruit
petal
Examples:
Monocots
areare
angiosperms
that
have plants
only
one
seedas
Refflesia
belongs
to
group
of seed
known
The stamens
thethe
male
reproductive
parts.
leaf.
angiosperms.
The female parts, or pistils, are found in the center of
most
flowers.
Dicots
produce
seeds with two
seed leaves.
A flower
is the reproductive
structure
of an
This
hollow structure is the ovary, which protects the
angiosperm.
seeds as they develop.
When a flower is still a bud, it is enclosed by leaflike
As the seed develops after fertilization, the ovary
structures called sepals.
changes into a fruit—a ripened ovary and other
structures
that enclose
one they
or more
seeds.
When the sepals
fold back,
reveal
the flower’s
colorful, leaflike petals.
Seed Plants
End of Section:
Angiosperms
Seed Plants
Plant Responses and Growth
-A plant’s growth response toward or
away from a stimulus is called a tropism.
*Positive tropism —grows toward the
stimulus
*Negative tropism —grows away from
the stimulus
Seed Plants
Plant Responses and Growth
-Types of tropisms:
*Thigmotropism —response to touch
*Phototropism—response to light
*Gravitropism—response to gravity
Seed Plants
Plant Hormones
-Chemicals called hormones control plant
tropisms.
*Example: Auxin controls phototropism
-Plant hormones also control germination,
the formation of flowers, stems, and leaves,
and the development and ripening of fruit.
Seed Plants - Plant Responses and Growth
Seasonal Changes
The amount of darkness a plant receives determines the
time of flowering in many plants. A plant’s response to these
seasonal changes is called photoperiodism.
Some plants
are day-neutral.
Their flowering
cycle is not
sensitive to
periods of light
and dark.
Seed Plants
Winter Dormancy
-Dormancy is a period when an organism’s
growth or activity stops.
-Dormancy helps plants survive freezing
temperatures and the lack of liquid water.
-This process begins with the change of leaf
color in the fall.
Seed Plants
*Leaves stop making chlorophyll and
other pigments become visible.
*Sugar and water from the leaves move
down the trunk and are stored for the
winter.
*Leaves fall off to prevent water loss
through transpiration.
Seed Plants
Life Spans of Angiosperms
-Three different life cycles of angiosperms:
*Annuals—complete their life cycle within
one growing season.
Ex: marigolds, petunias, wheat
*Biennials—complete their life cycle in
two years. Ex:parsley, celery, fox glove
*Perennials—live for more than two years
and flower each year. Ex: maple tree
Seed Plants - Plant Responses and Growth
Germination and Temperature
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.
Seed Plants - Plant Responses and Growth
Germination and Temperature
Reading Graphs:
What variable is plotted
on the horizontal axis?
What variable is plotted
on the vertical axis?
Horizontal axis–days;
vertical axis–total number of
germinated seeds
Seed Plants - Plant Responses and Growth
Germination and Temperature
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.
Seed Plants - Plant Responses and Growth
Germination and Temperature
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.
Seed Plants - Plant Responses and Growth
Germination and Temperature
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.
Seed Plants - Plant Responses and Growth
Relating Cause and Effect
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
Cause
Plant hormones
Germination
Forming flowers, stems,
leaves
Shredding leaves
Development and
ripening of fruit
Seed Plants - Plant Responses and Growth
Links on Plant Responses
Click the SciLinks button for links on plant responses.
Seed Plants
End of Section:
Plant Responses and
Growth
Seed Plants
Feeding the World
-World’s population: 6 billion
-World’s population by 2050: may be as
high as 10 billion
-How will farmers grow enough food?
Possible solutions include:
*Precision farming
*Hydroponics
*Genetic engineering
Seed Plants - Feeding the World
Identifying Main Ideas
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
Precision farming–
uses satellite images
and computer to
determine the amount
of water and fertilizer
needed.
Detail
Detail
Hydroponics–
plants are grown in
solutions of nutrients
instead of soil.
Genetic engineering–
genetic material is
altered to produce
plants with useful
qualities.
Seed Plants - Feeding the World
Links on Plants as Food
Click the SciLinks button for links on plants as food.
Seed Plants
End of Section:
Feeding the World
Seed Plants
Graphic Organizer
Seed plants
have
Stems
Leaves
are needed for
capture
Transport
Support
Sunlight
used in
Photosynthesis
Roots
provide
Anchorage
absorb
Water and
minerals
Seed Plants
End of Section:
Graphic Organizer