1. Chapter 30: The Evolution of Seed Plants
What are the 3 most important reproductive adaptations?
Reduction of the gametophyte
Advent of the seed – replaced spore
Evolution of pollen – male gametophyte
Air dispersal instead of sperm swimming

2. Figure 30.2 Gametophyte/sporophyte relationships
Sporophyte dependent
on gametophyte
(mosses and other
bryophytes).
(a)
Large sporophyte and
small, independent
gametophyte (ferns
and other seedless
vascular plants).
(b)
Microscopic female
gametophytes (n) in
ovulate cones
(dependent)
Sporophyte (2n),
the flowering plant
(independent)
Microscopic male
gametophytes (n)
inside these parts
of flowers
in pollen cones
Sporophyte (2n)
Reduced gametophyte dependent on sporophyte
(seed plants: gymnosperms and angiosperms).
(c)
Gametophyte
(n)
Sporophyte
(2n)

3. Chapter 30: The Evolution of Seed Plants
What are the 3 most important reproductive adaptations?
Reduction of the gametophyte
Advent of the seed – replaced spore as
Evolution of pollen – male gametophyte
How does an ovule become a seed?
Fertilization
Growth of the embryo

4. Figure 30.3 From ovule to seed
Unfertilized ovule. In this sectional
view through the ovule of a pine
(a gymnosperm), a fleshy
megasporangium is surrounded by
a protective layer of tissue called
an integument. (Angiosperms
have two integuments.)
(a)
Fertilized ovule. A megaspore
develops into a multicellular
female gametophyte. The
micropyle, the only opening
through the integument, allows
entry of a pollen grain. The
pollen grain contains a male
gametophyte, which develops
a pollen tube that discharges
sperm.
(b)
Gymnosperm seed. Fertilization
initiates the transformation of
the ovule into a seed, which
consists of a sporophyte embryo,
a food supply, and a protective
seed coat derived from the
integument.
(c)
Integument
Spore wall
Megasporangium
(2n)
Megaspore (n)
Male gametophyte
(within germinating
pollen grain) (n)
Female
gametophyte (n)
Egg nucleus (n)
Discharged
sperm nucleus (n)
Pollen grain (n)
Micropyle
Seed coat
(derived from
integument)
Food supply
(female
gametophyte
tissue) (n)
Embryo (2n)
(new sporophyte)

5. Chapter 30: The Evolution of Seed Plants
What are the 3 most important reproductive adaptations?
How does an ovule become a seed?
What’s the difference between a megaspore & a microspore?
Megasporangia  megaspores  female gametophytes (eggs)
Microsporangia  microspores  male gametophytes (sperm)
Recall seed plants are heterosporous
What are gymnosperms?
“naked seed” plants
Pines, spruce, fir, sequoia, yews, junipers, ginkgo
Most lumber & paper products
The gymnosperm life cycle…

6. Figure 30.6 The life cycle of a pine
Ovule
Key
Haploid (n)
Diploid (2n)
Megasporocyte (2n)
Integument
Longitudinal
section of
ovulate cone
Ovulate
cone
Pollen
Mature
sporophyte
(2n)
pollen cone
Microsporocytes
grains (n)
(containing male
gametophytes)
Micropyle
Germinating
pollen grain
Megasporangium
MEIOSIS
Sporophyll
Microsporangium

7. Figure 30.6 The life cycle of a pine
MEIOSIS
Surviving
megaspore (n)
Germinating
pollen grain
Archegonium
Integument
Egg (n)
Female
gametophyte
pollen grain (n)
Discharged
sperm nucleus (n)
Pollen
tube
Egg nucleus (n)
Ovule
Key
Haploid (n)
Diploid (2n)
Megasporocyte (2n)
Longitudinal
section of
ovulate cone
Ovulate
cone
Mature
sporophyte
(2n)
pollen cone
Microsporocytes
grains (n)
(containing male
gametophytes)
Micropyle
Megasporangium
Sporophyll
Microsporangium

8. Figure 30.6 The life cycle of a pine
MEIOSIS
Surviving
megaspore (n)
Germinating
pollen grain
Archegonium
Integument
Egg (n)
Female
gametophyte
pollen grain (n)
Discharged
sperm nucleus (n)
Pollen
tube
Egg nucleus (n)
Ovule
Key
Haploid (n)
Diploid (2n)
Megasporocyte (2n)
Longitudinal
section of
ovulate cone
Ovulate
cone
Mature
sporophyte
(2n)
pollen cone
Microsporocytes
grains (n)
(containing male
gametophytes)
Micropyle
Megasporangium
Sporophyll
Microsporangium
FERTILIZATION
Seed coat
(derived from
parent
sporophyte) (2n)
Food reserves
(gametophyte
tissue) (n)
Embryo
(new sporophyte)
(2n)
Seeds on surface
of ovulate scale
Seedling

9. Chapter 30: The Evolution of Seed Plants
What are the 3 most important reproductive adaptations?
How does an ovule become a seed?
What’s the difference between a megaspore & a microspore?
What are gymnosperms?
“naked seed” plants
Pines, spruce, fir, sequoia, yews, junipers, ginkgo
Most lumber & paper products
The gymnosperm life cycle…
What are angiosperms?
- Flowering plants
What is a flower?
- Reproductive structure of an angiosperm

10. Figure 30.7 The structure of an idealized flower
Anther
Filament
Stigma
Style
Ovary
Carpel
Petal
Receptacle
Ovule
Sepal
Stamen
Female structures
Male structures

11. Chapter 30: The Evolution of Seed Plants
What are the 3 most important reproductive adaptations?
How does an ovule become a seed?
What’s the difference between a megaspore & a microspore?
What are gymnosperms?
What are angiosperms?
What is a flower?
Reproductive structure of an angiosperm
What is a fruit?
Mature ovary
Helps seed dispersal

12. Figure 30.8 Some variations in fruit structure
Ruby grapefruit, a fleshy fruit
with a hard outer layer and
soft inner layer of pericarp
(b)
Tomato, a fleshy fruit with
soft outer and inner layers
of pericarp
(a)
Nectarine, a fleshy
fruit with a soft outer
layer and hard inner
layer (pit) of pericarp
(c)
Walnut, a dry fruit that
remains closed at maturity
(e)
(d)
Milkweed, a dry fruit that
splits open at maturity

13. Figure 30.9 Fruit adaptations that enhance seed dispersal
Wings enable maple fruits
to be easily carried by the wind.
(a)
Seeds within berries and other
edible fruits are often dispersed
in animal feces.
(b)
The barbs of cockleburs
facilitate seed dispersal by
allowing the fruits to
“hitchhike” on animals.
(c)

14. Chapter 30: The Evolution of Seed Plants
What are the 3 most important reproductive adaptations?
How does an ovule become a seed?
What’s the difference between a megaspore & a microspore?
What are gymnosperms?
What are angiosperms?
What is a flower?
What is a fruit?
The angiosperm life cycle….

15. Figure 30.10 The life cycle of an angiosperm
Mature flower on
sporophyte plant
(2n)
Key
Haploid (n)
Diploid (2n)
Anther
Ovule with
megasporangium (2n)
Male gametophyte
(in pollen grain)
Microspore (n)
MEIOSIS
Microsporangium
Microsporocytes (2n)
Generative cell
Tube cell
Surviving
megaspore
(n)
Ovary
Megasporangium
Female gametophyte
(embryo sac)
Antipodal cells
Polar nuclei
Synergids
Egg (n)
Pollen
tube
Sperm

16. Figure 30.10 The life cycle of an angiosperm
Pollen
tube
Sperm
Stigma
grains
Style
Discharged
sperm nuclei (n)
Egg
nucleus (n)
Mature flower on
sporophyte plant
(2n)
Key
Haploid (n)
Diploid (2n)
Anther
Ovule with
megasporangium (2n)
Male gametophyte
(in pollen grain)
Microspore (n)
MEIOSIS
Microsporangium
Microsporocytes (2n)
Generative cell
Tube cell
Surviving
megaspore
(n)
Ovary
Megasporangium
Female gametophyte
(embryo sac)
Antipodal cells
Polar nuclei
Synergids
Egg (n)

17. Figure 30.10 The life cycle of an angiosperm
Nucleus of
developing
endosperm
(3n)
Zygote (2n)
FERTILIZATION
Embryo (2n)
Endosperm
(food
supply) (3n)
Seed coat (2n)
Seed
Germinating
seed
Pollen
tube
Sperm
Stigma
grains
Style
Discharged
sperm nuclei (n)
Egg
nucleus (n)
Mature flower on
sporophyte plant
(2n)
Key
Haploid (n)
Diploid (2n)
Anther
Ovule with
megasporangium (2n)
Male gametophyte
(in pollen grain)
Microspore (n)
MEIOSIS
Microsporangium
Microsporocytes (2n)
Generative cell
Tube cell
Surviving
megaspore
(n)
Ovary
Megasporangium
Female gametophyte
(embryo sac)
Antipodal cells
Polar nuclei
Synergids
Egg (n)
Double fertilization

18. Chapter 30: The Evolution of Seed Plants
What are the 3 most important reproductive adaptations?
How does an ovule become a seed?
What’s the difference between a megaspore & a microspore?
What are gymnosperms?
What are angiosperms?
What is a flower?
What is a fruit?
The angiosperm life cycle….
Why is double fertilization important?
Synchronizes food development with embryo development
Prevents angiosperms from wasting nutrients on unfertilized ovules
What are the 2 general types of angiosperms?
Monocots
Eudicots

19. Dog rose (Rosa canina), a wild rose
Orchid
(Lemboglossum
rossii)
Monocot
Characteristics
Embryos
Leaf
venation
Stems
Root
Pollen
Flowers
Pollen grain with
one opening
Root system
Usually fibrous
(no main root)
Vascular tissue
scattered
Veins usually
parallel
One cotyledon
Two cotyledons
netlike
usually arranged
in ring
Taproot (main root)
usually present
three openings
Zucchini (Cucurbita
Pepo), female
(left) and male flowers
Pea (Lathyrus nervosus,
Lord Anson’s blue pea),
a legume
Dog rose (Rosa canina), a wild rose
Pygmy date palm
(Phoenix roebelenii)
Lily (Lilium
“Enchant-
ment”)
Barley (Hordeum vulgare),
a grass
Anther
Stigma
California
poppy
(Eschscholzia
californica)
Pyrenean oak
(Quercus
pyrenaica)
Floral organs
usually in
multiples of three
Floral organs usually
in multiples of
four or five
Filament
Ovary
Eudicot
MONOCOTS
EUDICOTS