SEEDLESS VASCULAR PLANTS Packet #70 Chapter #29. THE THEORY OF EVOLUTION CONNECTION Seedless vascular plants arose in the Carboniferous Period 420 – 360.
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SEEDLESS VASCULAR PLANTSPacket #70
Chapter #29
THE THEORY OF EVOLUTION CONNECTION
Seedless vascular plants arose in the Carboniferous Period 420 – 360 mya Phylum Rhinophyta are known as the oldest
seedless vascular plants These organisms left relics, fossils and coals Scientists believe that seed plants were
present during this evolutionary time period but were not dominant.
Seedless vascular plants became important as the swamps dried up and the global climate cooled.
TYPES OF SEEDLESS VASCULAR PLANTS
There are four phyla of seedless vascular plants. Phylum Polypodiophyta
Ferns Phylum Psilotophyta
Whisk ferns Phylum Equisetophyta
Horsetail Phylum Lycophyta
Club Mosses
IMPORTANT INFORMATION FOR VASCULAR PLANTS
LEAVES OF VASCULAR PLANTS
There are two types of leaves that may be found on seedless vascular plants Microphylls
Small and have a single vascular strand
Club mosses Megaphylls
Larger and have more than one vascular strand
Plants needed a flattened blade with more stomata for gas exchange
Ferns, horsetails and seed plants
Leaves of Vascular Plants Microphylls
KEYWORDS OF VASCULAR PLANTS
Homospory The production of
one kind of spore Bryophytes Whisk ferns Horsetails Most club mosses Most ferns
Spore gives rise to gametophyte plants that produce both egg and sperm cells.
KEYWORDS OF VASCULAR PLANTS II Heterospory
Production of two kinds of spores
Microspores Give rise to male
gametophytes that produce sperm cells
Megaspores Give rise to female
gametophytes that produce eggs.
Occurs in Certain club mosses Certain ferns ALL SEED PLANTS.
The “evolution” of heterospory was an essential step in the evolution of seeds.
SEED VASCULAR PLANTS—FERNS
PHYLUM PTEROPHYTASUBPHYLUM POLYPOIOPHYTATHE FERNS Largest and most
diverse group of seedless vascular plants. Have xylem and
phloem tissue Most have true roots More than 12,000
species have been described.
PHYLUM PTEROPHYTASUBPHYLUM POLYPOIOPHYTATHE FERNS Almost all species
are homosporous All have megaphylls. Found primarily in
moist tropical habitats Few are aquatic
FERNSFEATURES THAT DISTINGUISH FERNS AND OTHER SEEDLESS VASCULAR PLANTS FROM ALGAE AND BRYOPHYTES.
Comparison to Bryophytes Ferns have vascular
tissue Ferns have a
dominant sporophyte generation.
As in bryophytes, reproduction in ferns depends on water as a transport medium for their motile sperm cells.
REPRODUCTIVE CYCLE OF FERNS
PHYLUM PTEROPHYTASUBPHYLUM POLYPOIOPHYTATHE FERNS
Ferns display alternation of generation and they have a dominant sporophyte generation
Fern bodies consist of a rhizome (an underground stem), roots, and leaves (megaphylls).
Figure 29.12Page 585
PHYLUM PTEROPHYTASUBPHYLUM POLYPOIOPHYTATHE FERNS Sprophytes have
roots, rhizomes and leaves that are megaphylls.
Leaves, or fronds, bear sporangia in clusters called sori.
Meiosis of sporangia produces haploid spores.
PHYLUM PTEROPHYTASUBPHYLUM POLYPOIOPHYTATHE FERNS Spore germinates and
grow via mitosis into a gametophyte called haploid prothallus. Heart shaped and lacks
vascular tissue Anchored by rhizoids Bears antheridia and
archegonia Water is still required
for transportation of the flagellated sperm to the archegonium
Zygote grows into free-living sporophyte plant.
SEEDLESS VASCULAR PLANTS—WHISK FERNS
PHYLUM PTEROPHYTA SUBPHYLUM PSILOTOPHYTATHE WHISK FERNS Simplest vascular
plants Lack true roots and
leaves Consists of
dichotomously branching rhizomes
Have erect stems. Homosporous
sporophylls.
SEEDLESS VASCULAR PLANTS—HORSETAILS
PHYLUM PTEROPHYTASUBPHYLUM EQUISETOPHYTATHE HORSETAILS
Sporophytes have roots
Rhizomes Aerial stems
Hollow and jointed Leaves that are
reduced megaphylls
SEEDLESS VASCULAR PLANTS—CLUB MOSSES
PHYLUM LYCOPHYTATHE CLUB MOSSES
Small plants with rhizomes and short erect branches
Extant species have true roots and leaves that are microphylls.
REVIEW
REVIEW
Students List potential examination questions and/or here,
and on following slides, based on the packet.
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