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Unit 1: What is Biology?
Unit 2: Ecology
Unit 3: The Life of a Cell
Unit 4: Genetics
Unit 5: Change Through Time
Unit 6: Viruses, Bacteria, Protists, and Fungi
Unit 7: Plants
Unit 8: Invertebrates
Unit 9: Vertebrates
Unit 10: The Human Body
Unit 1: What is Biology?
Chapter 1: Biology: The Study of Life
Unit 2: Ecology
Chapter 2: Principles of Ecology
Chapter 3: Communities and Biomes
Chapter 4: Population Biology
Chapter 5: Biological Diversity and Conservation
Unit 3: The Life of a Cell
Chapter 6: The Chemistry of Life
Chapter 7: A View of the Cell
Chapter 8: Cellular Transport and the Cell Cycle
Chapter 9: Energy in a Cell
Unit 4: Genetics
Chapter 10: Mendel and Meiosis
Chapter 11: DNA and Genes
Chapter 12: Patterns of Heredity and Human Genetics
Chapter 13: Genetic Technology
Unit 5: Change Through Time
Chapter 14: The History of Life
Chapter 15: The Theory of Evolution
Chapter 16: Primate Evolution
Chapter 17: Organizing Life’s Diversity
Unit 6: Viruses, Bacteria, Protists, and Fungi
Chapter 18: Viruses and Bacteria
Chapter 19: Protists
Chapter 20: Fungi
Unit 7: Plants
Chapter 21:
Chapter 22:
Chapter 23:
Chapter 24:
What Is a Plant?
The Diversity of Plants
Plant Structure and Function
Reproduction in Plants
Unit 8: Invertebrates
Chapter 25: What Is an Animal?
Chapter 26: Sponges, Cnidarians, Flatworms, and
Roundworms
Chapter 27: Mollusks and Segmented Worms
Chapter 28: Arthropods
Chapter 29: Echinoderms and Invertebrate
Chordates
Unit 9: Vertebrates
Chapter 30: Fishes and Amphibians
Chapter 31: Reptiles and Birds
Chapter 32: Mammals
Chapter 33: Animal Behavior
Unit 10: The Human Body
Chapter 34: Protection, Support, and Locomotion
Chapter 35: The Digestive and Endocrine Systems
Chapter 36: The Nervous System
Chapter 37: Respiration, Circulation, and Excretion
Chapter 38: Reproduction and Development
Chapter 39: Immunity from Disease
Plants
What is a Plant?
The Diversity of Plants
Plant Structure and Function
Reproduction in Plants
Chapter 24 Introduction: Reproduction in Plants
24.1: Life Cycles of Mosses, Ferns, and Conifers
24.1: Section Check
24.2: Flowers and Flowering
24.2: Section Check
24.3: The Life Cycle of a Flowering Plant
24.3: Section Check
Chapter 24 Summary
Chapter 24 Assessment
What You’ll Learn
You will compare and contrast the life
cycles of mosses, ferns, and conifers.
You will sequence the life cycle of a
flowering plant.
You will describe the characteristics
of flowers, seeds and fruits.
Section Objectives:
• Review the steps of alternation of
generations.
Section Objectives:
• Survey and
identify methods
of reproduction
and the life
cycles of
mosses, ferns,
and conifers.
Alternation of Generations
• An alternation of generations consists of a
sporophyte stage and a gametophyte stage.
• All cells of a sporophyte are diploid.
• Certain cells of a sporophyte undergo
meiosis, which produces haploid spores.
Alternation of Generations
• These spores
undergo cell
divisions and
form a
multicellular,
haploid
gametophyte.
Alternation of Generations
• The female gamete is an egg and the male is
a sperm.
• When a sperm fertilizes an egg, a diploid
zygote forms. This is sexual reproduction.
• If the embryo develops to maturity, the cycle
can begin again.
Alternation of Generations
• This basic life cycle pattern is the same for
most plants. However, there are many
variations on this pattern within the plant
kingdom.
• Most people have never even seen the
female gametophyte of a flowering plant.
• Botanists usually refer to the bigger, more
obvious plant as the dominant generation.
Alternation of Generations
• The dominant generation lives longer and
can survive independently of the other
generation.
Dominant
generation
Asexual reproduction
• Most plants also can reproduce asexually by
a process called vegetative reproduction.
• In this type of reproduction, new plants are
produced from existing plant organs or parts of
organs.
• The new plants have the same genetic makeup
as the original plant.
Asexual reproduction
• The new
plants have
the same
genetic
makeup as
the original
plant.
Life Cycle of Mosses
• The gametophyte stage is the dominant
generation in mosses.
• A haploid moss spore can germinate and
grow to form a protonema (proh tuh NEE
muh). It is a small green filament of cells
that can develop into the gametophyte.
Life Cycle of Mosses
Mitosis
Developing sporophyte
Sporophyte
(2n)
Zygote (2n)
Sperm
Gametophyte (n)
Fertilization
Meiosis
SPOROPHYTE
GENERATION
2n
Egg
GAMETOPHYTE
GENERATION
n
Male
gametophyte (n)
Capsule
Female
gametophyte (n)
Capsule opens
releasing spores
Germinating
spores
Protonema
Life Cycle of Mosses
• Some moss gametophytes also reproduce by
vegetative reproduction.
• They can break into pieces when dry and
brittle then, when moisture returns, each
piece can grow and form a protonema then a
gametophyte.
Life Cycle of Ferns
• Unlike mosses, the dominant stage of the
fern life cycle is the sporophyte stage.
• The fern sporophyte includes the familiar
fronds.
• On the underside of some fronds are sori,
which are clusters of sporangia.
Life Cycle of Ferns
• Meiosis
occurs within
the sporangia,
producing
haploid
spores.
Life Cycle of Ferns
• A spore can
germinate to form
a heart-shaped
gametophyte
called a prothallus
• The prothallus
produces both
archegonia and
antheridia on its
surface.
Prothallus
Archegonium
Antheridium
Life Cycle of Ferns
• The flagellated sperm released by antheridia
swim through a film of water to eggs in
archegonia. If fertilization occurs, the
diploid zygote can develop into the
sporophyte.
• Once the sporophyte produces green fronds,
it can carry on photosynthesis and survive on
its own.
Life Cycle of Ferns
Click image to view movie.
Life Cycle of Ferns
• The mature
fern
sporophyte
consists of a
rhizome
from which
roots and
fronds grow.
Fronds
Rhizome
Roots
Life Cycle of Ferns
Growing prothallus
Spores (n)
Prothallus
Archegonium
Antheridium
Egg
Rhizoids
Meiosis
Sporangium
Sorus
GAMETOPHYTE
Sperm
GENERATION
n
Fertilization
SPOROPHYTE
GENERATION Zygote
2n
Fronds
Rhizome
Roots
Cell divisions
The Life Cycle of Conifers
• The dominant stage in conifers is the
sporophyte generation.
• The adult conifer produces
male and female cones on
separate branches of one
plant.
• Cones contain sporeproducing structures, or
sporangia, on their scales.
The Life Cycle of Conifers
• Female cones, which are larger than the male
cones, develop two ovules on the upper
surface of each cone scale.
• A megaspore is a female spore that
eventually becomes the female
gametophyte.
The Life Cycle of Conifers
• Male cones have sporangia that undergo
meiosis to produce male spores called
microspores.
• Each microspore can develop into a male
gametophyte, or pollen grain.
The Life Cycle of Conifers
• In conifers,
pollination is
the transfer
of pollen
grains from
the male
cone to the
female cone.
Egg
Pollen
grain
Micropyle
The Life Cycle of Conifers
• The opening of the ovule is called the
micropyle (MI kruh pile).
• The pollen grain adheres to a sticky drop of
fluid that covers the micropyle. As the fluid
evaporates, the pollen grain is drawn closer
to the micropyle.
The Life Cycle of Conifers
• Although pollination has occurred,
fertilization does not take place for at least a
year.
• As the pollen grain matures, it produces a
pollen tube that grows through the
micropyle and into the ovule.
The Life Cycle of Conifers
• A sperm nucleus from the male gametophyte
moves through the pollen tube to the egg.
• If fertilization occurs, a zygote forms.
• A seed coat forms around the ovule as the
mature seed is produced. Mature seed are
released when the female cone opens.
The Life Cycle of Conifers
Female cone
Ovule
Megaspores
Male cone
Microspores
Young
seedling
Adult
sporophyte
Microspore
mother cell
Meiosis
SPOTOPHYTE
GENERATION
2n
Seed
Male
gametophyte
(pollen grain)
Two
archegonia
with egg cells
GAMETOPHYTE
GENERATION
n
Fertilization
Seed coat
Sperm
nucleus
Cotyledons
Embryo
Female
gametophyte
Stored
food
One egg is
fertilized
Egg
Pollen
grain
Maturing pollen
Micropyle
grain
The Life Cycle of Conifers
Click image to view movie.
Question 1
Which of the following is NOT true of
gemmae?
A. They are an example of vegetative
reproduction.
B. They have the same genetic makeup as the
original plant.
C. They are diploid.
D. They are structures of liverworts.
The answer is C. Gemmae are haploid.
Question 2
Mitosis
Developing sporophyte
Sporophyte
(2n)
Zygote (2n)
Sperm
Gametophyte (n)
Fertilization
Meiosis
SPOROPHYTE
GENERATION
2n
Egg
GAMETOPHYTE
GENERATION
n
Male
gametophyte (n)
Capsule
Female
gametophyte (n)
Capsule opens
releasing spores
Germinating
spores
Protonema
This figure represents mosses because it reveals
a dominant gametophyte generation and
displays the presence of a protonema.
Question 3
A prothallus is a structure belonging to
_______.
A. ferns
B. liverworts
C. conifers
D. mosses
The answer is A, ferns.
Section Objectives:
• Identify
the organs
of a
flower.
• Examine how
photoperiodism
influences
flowering.
What is a flower?
• The process of
sexual
reproduction in
flowering plants
takes place in a
flower, which is a
complex structure
made up of several
organs.
The structure of a flower
• A flower’s
structure is
genetically
determined and
usually made up
of four kinds of
organs: sepals,
petals, stamens,
and pistils.
The structure of a flower
Modifications in flower structure
• A flower that
has all four
organs—sepals,
petals, stamens,
and pistils—is
called a
complete
flower.
Modifications in flower structure
• A flower that lacks one or more organs is
called an incomplete flower.
• For example the flowers
of plants such as sweet
corn, and grasses, have
no petals and are
adapted for pollination
by wind rather than by
animals.
Photoperiodism
• The relative lengths of daylight and darkness
each day have a significant effect on the rate
of growth and the timing of flower
production in many species of flowering
plants.
• The response of flowering plants to daily
daylight-darkness conditions is called
photoperiodism.
Photoperiodism
• Plant biologists originally thought that the
length of daylight controlled flowering.
• However, they now know that it is the length
of darkness that controls flowering, and that
the darkness must be uninterrupted.
Photoperiodism
• Plants are short-day plants, long-day plants,
day-neutral plants, or intermediate day
plants.
• A short-day plant flowers when the
number of daylight hours is shorter than
that of its critical period.
Photoperiodism
• Short-day plants usually flower sometime
during late summer, fall, winter, or spring.
Photoperiodism
• A long-day plant flowers when the number
of daylight hours is longer than that of its
critical period.
• Long-day
plants usually
flower in
summer, but
also will flower
if lighted
continually.
Photoperiodism
• Some plants will flower over a range in the
number of day-light hours. These plants are
called day-neutral plants.
• An intermediate-day plant will not flower if
days are shorter or longer than its critical
period.
Photoperiodism
• Photoperiodism is a
physioloical
adaptation of all
flowering plants that
ensures the
production of flowers
at a time when there
is an abundant
population of
pollinators.
Question 1
In flowers, the _______ receives the pollen.
A. peduncle
B. sepal
C. stigma
D. anther
The answer is C, stigma.
Stigma
Petals
Style
Ovary
Anther
Stamen
Filament
Sepal
Peduncle
Pistil
Question 2
Plants that flower year-round are most
likely to be _______.
A. short-day plants
B. long-day plants
C. intermediate-day plants
D. day-neutral plants
The answer is D, day-neutral plants.
Question 3
The _______ encircle the peduncle below the
petals.
A. stamens
B. anthers
C. sepals
D. styles
The answer is C, sepals.
Stigma
Petals
Style
Ovary
Anther
Stamen
Filament
Sepal
Peduncle
Pistil
Section Objectives:
• Survey and identify the methods of
reproduction, growth, and development in
flowering plants.
• Outline the processes in which cells
differentiate during the formation of seeds
and fruits and during seed germination.
The Life Cycle of an Anthophyte
• The life cycle of flowering plants is similar to
that of conifers in many ways.
Pollen sac with microspore
mother cells
Microspores in
fours
Pollen grain
Meiosis
Anther
Ovule with
megaspore
mother cell
Sperm
Four megaspores
Egg
Tube
nucleus
Pollen
tube
GAMETOPHYTE Female
gametophyte
GENERATION
n
Fertilization
Adult
sporophyte
plant
Young
seedling
SPOROPHYTE
GENERATION
2n
Double
fertilization
Male
gametophyte
Ovary
Pollen tube
Zygote
Endosperm
nucleus
Germinating
seed
Seed
Fruit
with
seeds
The Life
Cycle of an
Anthophyte
Development of the female gametophyte
• In anthophytes, the female gametophyte is
formed inside the ovule within the ovary.
• In the ovule, a cell undergoes meiosis and
produces haploid megaspores.
• In most flowering plants, the megaspore’s
nucleus undergoes mitosis three times,
producing eight haploid nuclei.
Development of the female gametophyte
• These eight nuclei make up the female
gametophye. Cell walls form around each of
six nuclei, one of which is now called the egg
cell.
• The two remaining nuclei, which are called
polar nuclei, are enclosed in one cell.
• This cell, the central cell, is located at the
center of the female gametophyte.
Development of the female gametophyte
Embryo sac
(female
gametophyte)
• The other
five cells
eventually
disintegrate.
Central cell
Ovule
Egg cell
Micropyle
Development of the male gametophyte
• Haploid microspores are produced by meiosis
within the pollen sac.
• The nucleus of each microspore undergoes
mitosis.
• A thick, protective wall surrounds these two
nuclei. This structure is the immature male
gametophyte, or pollen grain.
Development of the male gametophyte
• When the pollen grains mature, the anther
usually splits open.
Pollen
sacs
Microspore
mother cell (2n)
MEIOSIS
Generative
nucleus
Tube
nucleus
ANTHER
Pollen grain
(male gametophyte)
Microspores
(n)
Pollination
• In anthophytes, pollination is the transfer of
the pollen grain from the anther to the stigma.
• Depending on the type of flower, the pollen
can be carried to the stigma by wind, water,
or animals.
• Most anthophytes that are pollinated by
animals produce nectar in their flowers.
Pollination
• Nectar is a liquid made up of proteins and
sugars and usually collects in the cuplike area
at the base of petals.
• Animals, such as insects and birds, brush up
against the anthers while trying to get to the
nectar.
Pollination
• The pollen
that attaches
to them can
be carried to
another
flower,
resulting in
pollination.
Pollination
• Some of the
bright, vivid
flowers attract
pollinators,
such as
butterflies and
bees.
Pollination
• Flowers that are pollinated by beetles and
flies have a strong scent but are often dull in
color.
• Many flowers have structural adaptations
that favor cross-pollination—pollination
between two plants of the same species.
• This results in greater genetic variation
because a sperm from one plant
fertilizes an egg from another.
Fertilization
• Inside each pollen grain are two haploid nuclei,
the tube nucleus and the generative nucleus.
Stigma
Style
Pollen grain
Two sperm
nuclei
Pollen tube
Tube nucleus
Ovary
Central cell
Ovule
Egg cell
Fertilization
• The tube nucleus directs the growth of the
pollen tube down through the pistil to the
ovary.
• The generative nucleus divides by mitosis,
producing two sperm nuclei.
Fertilization
• The sperm nuclei move through the pollen
tube to a tiny opening in the ovule called the
micropyle.
Pollen grain
Stigma
Style
Two sperm
nuclei
Pollen tube
Tube nucleus
Ovary
Central cell
Ovule
Egg cell
Fertilization
Double Fertilization
• One of the sperm unites with
the egg forming a diploid
zygote, which begins the new
sporophyte generation.
• The other sperm nucleus
fuses with the central
cell, which contains the
polar nuclei, to form a
cell with a triploid (3n)
nucleus.
One sperm
fertilizes the
egg cell (2n)
One sperm
fertilizes the
central cell
(3n)
Fertilization
• This process, in which one sperm fertilizes
the egg and the other sperm joins with the
central cell, is called double fertilization.
• The triploid nucleus will divide many times,
eventually forming the endosperm of the
seed.
• The endosperm is food storage tissue that
supports development of the embroyo in
anthophyte seeds.
Seeds and Fruits
Fruit
Ovary
Ovules
Sepals
Stamen
Fused
petals
Seed formation
• After fertilization takes place, seed
development begins.
• Inside the ovule, the zygote divides and
develops into the embryo plant.
• The triploid central cell develops into the
seed’s endosperm.
Seed formation
• The wall of the
ovule becomes
the seed coat,
which can aid in
seed dispersal
and help protect
the embryo until
it begins
growing.
Seed formation
Click image to view movie.
Fruit formation
• As the seeds develop, the surrounding ovary
enlarges and becomes the fruit.
• A fruit is the structure that contains the seeds
of an anthophyte.
• A fruit is as unique to an anthophyte as is its
flower, and many anthophytes can be
identified by examining their fruits.
Fruit formation
• Some plant foods
that we call
vegetables or
grains are actually
fruits.
• For example, green
peppers are fleshy
fruits that are often
referred to as
vegetables.
Fruit formation
Click image to view movie.
Seed dispersal
• The dispersal of seeds is important because it
reduces competition for sunlight, soil, and
water between the parent plant and its
offspring.
• Animals such as
raccoons, deer,
bears, and birds
help distribute
many seeds by
eating fruits.
Seed dispersal
• Seeds that are eaten usually pass through the
digestive system undamaged and are
deposited in the animal’s wastes.
• Plants that grow in or
near water, produce
fruits or seeds with air
pockets in the walls that
enable them to float and
drift away from the
parent plant.
Seed dispersal
• The ripened fruits
of many plants
split open to
release seeds with
structural
adaptations for
dispersal by wind
or by clinging to
animal fur.
Seed germination
• At maturity, seeds are fully formed.
• The seed coat dries and hardens, enabling
the seed to survive environmental
conditions that are unfavorable to the parent
plant.
• The seeds of some plant species must
germinate within a short period of time or
die.
Seed germination
• The seeds of some plant species can remain
in the soil until conditions are favorable for
growth and development of the new plant.
• This period of inactivity in a mature seed is
called dormancy. The length of time a seed
remains dormant can vary from one species
to another.
Seed germination
• Even under harsh conditions, the seeds of
desert wildflowers and some conifers can
survive dormant periods of 15 to 20 years.
Requirements for germination
• Germination is the beginning of the
development of the embryo into a new
plant.
Requirements for germination
• Water is important because it activates the
embryo’s metabolic system.
• Once metabolism has begun, the seed must
continue to receive water or it will die.
• Just before the seed coat breaks open, the
rate of respiration in the plant embryo
increases rapidly.
• Some seeds have specific requirements for
germination.
Requirements for germination
• For example, some germinate more readily
after they have passed through the acid
environment of an animal’s digestive
system.
• The seeds of some
conifers will not
germinate unless
they have been
exposed to fire.
Requirements for germination
Vegetative reproduction
• The roots, stems, and leaves of plants are
called vegetative structures.
• When these structures produce a new
plant, it is called vegetative reproduction.
Vegetative reproduction
• Some modified stems of anthophytes, such
as potato tubers, can produce a new plant
from each “eye” or bud.
• Using vegetative
reproduction to grow
numerous plants
from one plant is
frequently referred
to as vegetative
propagation.
Vegetative reproduction
• Even smaller pieces of plants can be used
to grow plants by tissue culture.
• Pieces of plant meristematic tissue are
placed on nutrient agar in test tubes or petri
dishes.
Vegetative reproduction
• The plants grown from cuttings and tissue
cultures have the same genetic makeup as
the plants from which they came and are
botanical clones.
• There is great diversity in the flowers,
seeds, fruits, and vegetative structures of
anthophytes.
• Anthophytes are divided into families
based on these differences.
Cocoa
Sterculiaceae
Magnolia
Cactuc
Cactaceae
Caraway
Apiaceae
Magnoliaceae
Chicory
Asteraceae
Milkweed
Coleus
Asclepiadaceae
Oak
Fagaceae
Lamiaceae
Raspberry
Rosaceae
Palm
Dicots
Arecaceae
Lily
Grass
Liliaceae
Monocots
Poaceae
Orchid
Orchidaceae
Protists
Question 1
Most anthophytes that produce nectar are
pollinated by _______.
A. wind
B. animals
C. water
D. machines
The answer is B, animals.
Question 2
In anthophytes, _______ is the transfer of
immature male gametophytes from the anther
to the stigma.
A. double fertilization
B. germination
C. pollination
D. vegetative reproduction
The answer is C, pollination.
Question 3
Why can insects see some flower marking
that humans cannot see?
Many of these flower
markings are visible
only to organisms,
like insects, that can
detect ultraviolet
light. The human eye
cannot detect
ultraviolet light.
Question 4
What is the difference between the functions of
a tube nucleus and a generative nucleus?
Answer
The tube nucleus directs the growth of the
pollen tube down through the pistil to the
ovary. The generative nucleus divides by
mitosis, producing two sperm nuclei.
Life Cycles of Mosses, Ferns, and
Conifers
• The gametophyte generation is dominant in
mosses. Archegonia and antheridia form on
separate or the same gametophyte. Fertilization
requires a film of water on the gametophyte.
• Archegonia and antheridia develop on a
prothallus, the fern gametophyte. Fertilization
requires a film of water on the gametophyte.
The sporophyte generation is dominant in
ferns.
Life Cycles of Mosses, Ferns, and
Conifers
• Conifers have cones in which a male or female
gametophyte forms. Sperm nuclei form in
pollen grains and eggs form in ovules. The
embryo is protected in a seed.
Flowers and Flowering
• Flowers are made up of four organs: sepals,
petals, stamens, and pistils. A flower lacking
any organ is called incomplete. Complete
flowers have all four organs.
• Photoperiodism—responses of flowering plants
to daylight-darkness conditions affects flower
production. Plants are called short-day, longday, day-neutral, or intermediate depending
upon their photoperiodic response.
The Life Cycle of a Flowering Plant
• The male gametophyte develops from a
microspore in the anther. The female
gametophyte develops from a megaspore in
the ovule.
• Double fertilization occurs when a sperm
nucleus joins with an egg to form a zygote.
The second sperm nucleus joins the central
cell to form endosperm.
The Life Cycle of a Flowering Plant
• Fruits and seeds are modified for dispersal.
Seeds can stay dormant for a long time before
they germinate.
Question 1
During the life cycle of conifers, microspores
develop into _______.
A. archegonia
B. micropyles
C. megaspores
D. pollen grains
The answer is D, pollen grains.
Question 2
How is photoperiodism associated with
pollination?
Answer
Photoperiodism is a physiological adaptation
of all flowering plants that ensure the
production of flowers at a time when there is
an abundant population of pollinators.
Question 3
The process whereby one sperm fertilizes the
egg and the other sperm joins with the central
cell is called _______.
A. photoperiodism
B. vegetative reproduction
C. double fertilization
D. germination
Double Fertilization
The answer is C, double
fertilization.
One sperm
fertilizes the
central cell
(3n)
One sperm
fertilizes the
egg cell (2n)
Question 4
The _______ is the structure that contains the
seed of an anthophyte.
A. fruit
B. stamen
C. ovule
D. egg cell
The answer is A, fruit.
Question 5
Food storage tissue that supports
development of the embryo in anthophyte
seeds is the _______.
A. megaspore
B. microspore
C. endosperm
D. ovule
The answer is C, microspore.
Question 6
The dormancy period of a seed ends
with _______.
A. fertilization
B. germination
C. pollination
D. dispersal
The answer is B, germination.
Question 7
The radicle of a plant embryo develops
into a _______.
A. stem
B. pair of leaves
C. cotyledon
D. root
The answer is D, root.
Question 8
What pushes a seedling upward through the
soil when it emerges from its seed?
Answer
This push or force results from water
pressure inside the seedling’s cells.
Question 9
A flower that naturally has four petals, eight
stamens, and one pistil is an example of a (n)
_______.
A. dicot
B. incomplete flower
C. monocot
D. male flower
The answer is A, dicot.
Question 10
In flowering plants, _______ begins the
sporophyte generation.
A. meiosis
B. germination
C. fertilization
D. pollination
The answer is C, fertilization.
Photo Credits
• National Cotton Council of America
• PhotoDisc
• Photo Essentials
• Matt Meadows
• Digital Stock
• USDA
• Corbis
• Alton Biggs
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