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CHAPTERS 25 & 27: Plants
High School Biology Class
CHAPTER 25-1
SEXUAL REPRODUCTION IN
SEEDLESS PLANTS
Reproduction in Seedless Plants
 Nonvascular & Seedless Vascular (seedless
plants) reproduce by making gametophyte
spores.
A) Archegonium structures produce egg
spores that are large, contain lots of
cytoplasm, and cannot move.
B) Antherdium structures produce sperm
spores that are small, have flagella, and
reach eggs by swimming through water.
Reproduction in Seedless Plants
 Fertilization for seedless plants usually
occurs during or soon after rain, when the
spores are covered with water.
 Only then can the sperm swim to the egg.
 Once together they form a sporophyte,
which can then continue its life cycle.
CHAPTER 25-2
SEXUAL REPRODUCTION IN
SEED PLANTS
Reproduction in Seed Plants
 Gymnosperms & Angiosperms (seed plants)
do not release spores in rain like other plants.
 Instead, their spores remain within their
tissues and develop into male or female
gametophyte seeds.
Reproduction in Seed Plants
Examples of Seed Structures:
a) Pollen Grain - male gametophyte
(wind and animals transport pollen grains)
b) Ovule - female gametophyte
(remains with the plant)
Reproduction Terms
 Seed Coat - the hardened outer cell layers of
an ovule that protects the embryo.
 Pollination - transfer of pollen grains from the
male structures to the female structures.
Reproduction Parts
 Cotyledon - leaf-like structures (seed
leaves) that are a part of the embryo.
a. Gymnosperms – have two or more cotyledons
b. Angiosperms:
i. Monocots – have 1 cotyledon
ii. Dicots – have 2 cotyledons
Reproduction in Seed Plants
 Gymnosperms – type of plant where
gametophytes develop within cones.
 Angiosperms – type of plant where the
gametophytes develop within flowers.
Angiosperm - Flowers
Flowers Have Four Whorls:
1. Sepals – the outermost (first) whorls for
protection when the flower is a bud.
2. Petals – the second whorls are used to
attract the pollinators.
Angiosperm - Flowers
3. Stamens – third whorl that make pollen.
Anther – pollen-producing sac on top of stamen.
4. Pistils – fourth whorl produces ovules.
Ovary – the pistil’s swollen lower portion is the
spot where the ovules develop.
Style – the stalk that rises from ovary.
Stigma – the swollen, sticky tip of style.
Examples of Flower Pollinators:
a. Bees
b. Flies
c. Moths
d. Hummingbirds
e. Bats
f. Wind
CHAPTER 25-3
ASEXUAL REPRODUCTION
IN PLANTS
CHAPTER 27-1
HOW PLANTS GROW AND
DEVELOP
Seed Growth
 Seeds sprout in response to the
environmental conditions.
 A seed cannot sprout until water and
oxygen penetrate the seed coat.
Seed Growth
 Germination - process in which a plant
embryo resumes its growth.
Patterns of Growth
1) Primary Growth – growth that
increases the strength or height of a
plant.
Apical Meristems – located at the lips of
stems & roots perform primary growth.
Patterns of Growth
2) Secondary Growth – growth that
increases the width of stems and roots.
Vascular Cambium – meristems that lie
under the cuticle (bark) produce
secondary growth.
Three Types Of Plants
Based On Life Spans of the Plant
A) Perennials:
 A plant that lives for several years.
Examples:
i. Herbaceous - Chrysanthemums, Daffodils, Irises
ii. Woody - Trees, Shrubs, Vines
B) Annuals:
 A plant that completes its life cycle and
then dies within one growing season.
Examples:
Sunflowers, Beans, Corn, Weeds
C) Biennials:
 Flowering plants that take two growing
seasons to complete their life cycle.
1st Season: produces roots and shoots
- 2nd Season: produces flowering stalk
-
Examples:
Carrots, Parsley, Onions
Any Questions?
 “The mind has exactly the same power as the
hands; not merely to grasp the world, but to
change it.”
--Colin Wilson
 “Hard work spotlights the character of people:
Some turn up their sleeves, some turn up
their noses, and some don’t turn up at all.”
--Sam Ewig