Biology, Seventh Edition
Solomon • Berg • Martin
Chapter 26
The Plant Kingdom:
Seedless Plants
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 26 The Plant Kingdom: Seedless Plants
• Environmental challenges of
living on land required evolution
of adaptations
• Anatomical
• Physiological
• Reproductive
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Biology, Seventh Edition
CHAPTER 26 The Plant Kingdom: Seedless Plants
• Examples of adaptations
• Cuticle to prevent water loss
• Stomata for photosynthesis
• Alternation of generations
–Gametophyte
–Sporophyte
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Biology, Seventh Edition
CHAPTER 26 The Plant Kingdom: Seedless Plants
Basic
plant life cycle
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 26 The Plant Kingdom: Seedless Plants
Generalized reproductive structures
of algae and plants
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Biology, Seventh Edition
CHAPTER 26 The Plant Kingdom: Seedless Plants
• Alternation of generations, cont.
• Gametophyte produces gametes
by mitosis
• Gametes fuse to form zygote
• Zygote develops into embryo
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Biology, Seventh Edition
CHAPTER 26 The Plant Kingdom: Seedless Plants
• Alternation of generations, cont.
• Mature sporophyte develops from
embryo, producing sporogenous
cells
• Sporogenous cells undergo
meiosis to form spores
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 26 The Plant Kingdom: Seedless Plants
• Examples of adaptations, cont.
• Gametangia protect gametes
–Antheridia
–Archegonia
• Xylem conducts water and sugar
nutrients
• Phloem conducts dissolved sugar
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Biology, Seventh Edition
CHAPTER 26 The Plant Kingdom: Seedless Plants
Plant
gametangia
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Biology, Seventh Edition
CHAPTER 26 The Plant Kingdom: Seedless Plants
• Plants are probably descended
from charophytes
• Both have similar biochemical
characteristics
–Same photosynthetic pigments
–Same cell wall components
–Same carbohydrate storage material
–Similarities in fundamental processes
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Biology, Seventh Edition
CHAPTER 26 The Plant Kingdom: Seedless Plants
Plant evolution
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Biology, Seventh Edition
CHAPTER 26 The Plant Kingdom: Seedless Plants
• Features distinguishing
bryophytes from green algae
and other plants
• Bryophytes have cuticle, stomata, etc.
• Bryophytes are non-vascular and do
not have xylem or phloem
• Bryophytes have a dominant
gametophyte generation
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 26 The Plant Kingdom: Seedless Plants
• The three phyla of bryophytes
• Phylum Bryophyta (gametophytes
grow from protonema)
• Phylum Hepaticophyta (some have
gametophytes that are thalli)
• Phylum Anthocerotophyta (thalloid
gametophytes)
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Biology, Seventh Edition
CHAPTER 26 The Plant Kingdom: Seedless Plants
• The life cycle of mosses
• Green moss gametophyte bears
archegonia and/or antheridia
• During fertilization, sperm cell fuses
with egg cell in archegonium
• Zygote develops into embryo
• Embryo develops into moss
sporophyte
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Biology, Seventh Edition
Life cycle of mosses
CHAPTER 26 The Plant Kingdom: Seedless Plants
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 26 The Plant Kingdom: Seedless Plants
• The life cycle of mosses, cont.
• Moss sporophyte is attached to
gametophyte
• Meiosis occurs in capsule of
sporophyte to produce spores
• When spore germinates, it
germinates into a protonema that
forms buds
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Biology, Seventh Edition
CHAPTER 26 The Plant Kingdom: Seedless Plants
Copyright © 2005 Brooks/Cole — Thomson Learning
Life cycle of
Marchantia
polymorpha
Biology, Seventh Edition
CHAPTER 26 The Plant Kingdom: Seedless Plants
• Features distinguishing ferns
and other seedless vascular
plants from algae and
bryophytes
• Ferns and fern allies have
adaptations including
–Vascular tissues
–A dominant sporophyte generation
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Biology, Seventh Edition
CHAPTER 26 The Plant Kingdom: Seedless Plants
Evolution of
microphylls and
megaphylls
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 26 The Plant Kingdom: Seedless Plants
• The four phyla of seedless
vascular plants
•
•
•
•
Phylum Polypodiophyta
Phylum Psilotophyta
Phlylum Equisetophyta
Phylum Lycophyta
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Biology, Seventh Edition
CHAPTER 26 The Plant Kingdom: Seedless Plants
• The life cycle of ferns
• Fern sporophytes have megaphylls
• Their fronds bear sporangia in
clusters (sori)
• Meiosis in sporangia produces
haploid spores
• Prothalli develop from these and bear
both archegonia and antheridia
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Biology, Seventh Edition
CHAPTER 26 The Plant Kingdom: Seedless Plants
Life cycle
of ferns
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 26 The Plant Kingdom: Seedless Plants
• Generalized life cycles of
homosporous and
heterosporous plants
• Homospory
–Bryophytes, whisk ferns, horsetails, most
club mosses, and most ferns
–Spores give rise to gametophyte plants
producing both egg and sperm cells
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 26 The Plant Kingdom: Seedless Plants
• Generalized life cycles of
homosporous and
heterosporous plants, cont.
• Heterospory
–Some clubmosses, some ferns, and all
seed plants
–Microspores give rise to male
gametophytes
–Megaspores give rise to female
gametophytes
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Biology, Seventh Edition
CHAPTER 26 The Plant Kingdom: Seedless Plants
Basic life cycle
of
heterosporous
plants
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Biology, Seventh Edition
CHAPTER 26 The Plant Kingdom: Seedless Plants
Life cycle of
Selaginella
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