Figure 29.0 Ferns
Figure 29.1 Some highlights of plant evolution
Figure 29.12 Fossilized spores and sporophyte tissue
Earliest fossils are 500 million years old
Similarities between the
Charophyceans and plants
Why are plants thought to have
evolved from Green Algae?
Rosette
complexes
Peroxisome
enzymes
Flagellated
sperm
Phragmoplast
formation
1
Apical Meristems
Derived characters in plants
Allow plants to elongate along all axes
Spores are formed inside sporangia and have
tough outer coverings formed from
sporopollenin
Alternation of Generations (does
not occur in Charophyceans)
Charophyceans)
Multicellular Gametangia
Specialized structures
where gametes are
formed
Multicellular dependent embryos
Zygotes are retained
and develop in the
maternal tissues
Antheridia
Archegonia
2
Terrestrial adaptations (derived
characters in plants)
Adaptations for water conservation
Adaptations for transport
Cuticle
Stomata
Xylem and phloem
Adaptations for support
They had to develop some new way of
transporting sperm to eggs
Non vascular plants
Gametophyte is dominant stage of lifecycle
Most lack conducting tissue
Rhizoids anchor plants
Reproduction:
Spore germinates to become the protonema
Male gametophyte contains Antheridia
Female gametophyte contains Archegonia
Nonvascular Plants: Phyla
Bryophyta,
Bryophyta, Hepatophyta and
Anthocerophyta
Mosses, liverworts, hornworts
3
Fig.
20.11
Fig. 20.12
The sporophyte in Bryophyta
develops WITHIN the
gametophyte
Consists of a foot,
seta and capsule
Capsule
Figure 29.16x Moss life cycle
Is nutritionally
dependent upon the
gametophyte
Calyptra
peristome
Figure 29.18 A moss sporangium with a “spore“spore-shaker” tip
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Figure 29.19x A peat moss bog in Norway
Phylum Hepatocyta
Liverwort archegonia
Female gameotphytes
Gemmae cups
Antheridia
Male gametophytes
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Anthocerophyta - Hornworts
Vascular plants
Pteridophytes, Gymnosperms and
Angiosperms
Seedless Vascular Plants (Pteridophytes):
Vascular plants all
share the following
Vascular tissue with
lignified cells for water
and food transport
Independent branched
sporophytes
Phyla Lycophyta and Pterophyta
Cooksonia,
Cooksonia, a vascular plant of the Silurian Age
True roots with lignified vascular tissue
Leaves
Microphylls
Megaphylls
Sporophyte is dominant generation
Evolution from homospory to heterspory
Evolved about 400 mya
Grew to 50 cm
Figure 29.22 Hypotheses for the evolution of leaves
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Lycophyta:
Lycophyta: Lycopodium
Pterophyta:
Pterophyta: Psilotum
Lycophyta
Phylum Pterophyta:
Pterophyta:
Phylum Pterophyta:
Pterophyta:
Equisetum
Polypodium
Club mosses
Have microphylls
Have some shoots
ending in sporophylls
Figure 29.23 The life cycle of a fern
Sphenophyta:
Sphenophyta:
the Horsetails
Produce cones at tips
Cones are clusters of
sporophylls
Have hollow stems for
transport of Oxygen
to rhizomes
underground
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Figure 29.23x7 Life cycle of a fern: archegonia
Figure 29.25 Artist’s conception of a Carboniferous forest based
based on fossil evidence
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