SEEDLESS VASCULAR PLANTS

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SEEDLESS VASCULAR PLANTS

• Packet 70
• Chapter 29

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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.

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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

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IMPORTANT INFORMATION FOR VASCULAR PLANTS
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LEAVES OF VASCULAR PLANTS

• Leaves of Vascular Plants

• Microphylls

• 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

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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.

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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.

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SEED VASCULAR PLANTSFERNS
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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.

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PHYLUM PTEROPHYTASUBPHYLUM POLYPOIOPHYTATHE
FERNS

• Almost all species are homosporous
• All have megaphylls.
• Found primarily in moist tropical habitats
• Few are aquatic

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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.

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REPRODUCTIVE CYCLE OF FERNS
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PHYLUM PTEROPHYTASUBPHYLUM POLYPOIOPHYTATHE
FERNS

• Figure 29.12Page 585

• 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).

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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.

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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.

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SEEDLESS VASCULAR PLANTSWHISK FERNS
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PHYLUM PTEROPHYTA SUBPHYLUM PSILOTOPHYTATHE
WHISK FERNS

• Simplest vascular plants
• Lack true roots and leaves
• Consists of dichotomously branching rhizomes
• Have erect stems.
• Homosporous sporophylls.

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SEEDLESS VASCULAR PLANTSHORSETAILS
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PHYLUM PTEROPHYTASUBPHYLUM EQUISETOPHYTATHE
HORSETAILS

• Sporophytes have roots
• Rhizomes
• Aerial stems
• Hollow and jointed
• Leaves that are reduced megaphylls

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SEEDLESS VASCULAR PLANTSCLUB MOSSES
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PHYLUM LYCOPHYTATHE CLUB MOSSES

• Small plants with rhizomes and short erect
  branches
• Extant species have true roots and leaves that
  are microphylls.

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REVIEW
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REVIEW

• Students
• List potential examination questions and/or here,
  and on following slides, based on the packet.