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A.
B.
C.
D.
Male Structures
Female Structures
Neither
Both
Male! These are stamen with white
filaments & large anthers carrying pollen.
A.
B.
C.
D.
Male Structures
Female Structures
Neither
Both
Female! This is the carpel, which leads
down to the ovary.
A.
B.
C.
D.
Male Structures
Female Structures
Neither
Both
Both! You can see the stamen & the
carpel.
If flowers can have male & female parts,
can they self-pollinate?
Yes!
• Flowers can self-pollinate OR cross-pollinate.
How do plants
reproduce?
Plant Reproduction
Alternation of Generations
• Plants have 2 reproductive life cycles:
– Diploid Sporophyte Generation
– Haploid Gametophyte Generation
• Applies to Bryophytes,
Seedless Vascular Plants,
Gymnosperms,
& Angiosperms
Sporophyte & Gametophyte Generation
• Our human bodies undergo
meiosis to create gametes.
Once an egg is fertilized, it
undergoes mitosis for the
baby to grow & develop.
• Plants undergo haploid
gametophyte generation to
create gametes. Once
fertilization occurs, the plant
switches to diploid
sporophyte generation to
grow.
Diploid (2N) Sporophyte Generation
• Familiar, recognizable form of a plant
• Develops from a zygote
• Cell replication through mitosis
Haploid (N) Gametophyte Generation
• Gamete cells created from meiosis
• Sperm & egg cells
– Pollen & ovules
• Combine to form a zygote, which grows into
the sporophyte generation
Alternation of
Generations
The actual plant that you think
of is the sporophyte (2n).
The sporophyte undergoes meiosis to produce the gametophyte (1n).
The male gametophyte is pollen & the female gametophyte is the
ovule.
The gametophytes (pollen & ovule) produce gametes (sperm & egg).
When gametes fuse, a new sporophyte will develop.
Gametophytes
• Gymnosperms: cones
– Pollen forms in the male pollen cones.
– Ovules form in the female seed cones.
• Angiosperms: flowering plants
– Flower is the reproductive structure, with male (stamen) &
female (carpel) parts
Is pollen a male structure or a female
structure?
A.
B.
C.
D.
Male Structure
Female Structure
Neither
Both
Male! Pollen forms on the stamen.
Pollination
• Process in which pollen is spread
• Plants can be self-pollinated or cross-pollinated
– Wind, insects, & animals can all help pollinate
The flower of an
angiosperm helps attract
birds & insects!
Fertilization
Process where sperm from the pollen combines with an ovule
• 2 fertilizations occur in
angiosperms (flowering
plants):
– 1 sperm nuclei fuses with an
ovule to produce a diploid
zygote (plant embryo).
– A second sperm nuclei fuses
with 2 polar nuclei (formed
from meiosis in the ovary) to
produce the endosperm.
Double Fertilization
• 1st fertilization: 1 sperm nucleus
combines with 1 egg nucleus =
zygote (now 2n)
• 2nd fertilization: 2 ovules have
joined together in the ovary
(making them diploid)
• A second sperm nucleus will fuse
with these (making it triploid, or
3n)
– This becomes the endosperm.
Anatomy of a Seed
• Endosperm: food source for the plant embryo
• Cotyledon: seed leaf of plant embryo (will become the
first leaves)
• Seed Coat: protection
Which of the following does not play a direct
role in sexual reproduction?
A.
B.
C.
D.
Petal
Ovary
Anther
Style
Petals!
What is the function of the endosperm in a
fertilized ovule?
A. Protect the seed from high
temperatures.
B. Become the leaves of the plant.
C. Provide a food source for the seed.
D. Protect the seed from drought.
Food
Source!
Video
Fruits
• Ripened ovary that contains angiosperm seeds
- Strawberries, peaches, apples, peas, corn, beans,
cucumbers, and tomatoes
The ovary wall
surrounding the fruit may
be fleshy (like a grape) or
tough (like a bean pod)!
Vegetables
• Other edible parts of a plant, like the roots,
tubers, bulbs, stems, leaves, or flower parts
The part of the carrot
that you eat is the root of
the plant!
Plant Reproduction
• In your groups, put the cards in the correct sequence of plant
reproduction.
• When you finish, raise your hand & I will check it!
• Once it is correct, I will give
you your exit ticket!