Introduction to Plant Diversity

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Introduction to Plant Diversity

• Land plant origins, phylogenetics and
  introduction to vascular plants Lycophyta

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Meiosis vs. Mitosis (a review!)
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Alternation of Generations
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Phylogenetics - a few terms

• Monophyletic - having a common, single origin
• Clade - a monophyletic group in a phylogeny
• Sister taxa - two clades that have a common
  ancestor
• Outgroup - a distantly related taxon for reference

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Hybridization
?!?!
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The tree of life
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Land plants
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What is a plant?

• Chlorophylls a b
• Double membraned chloroplast
• Starch stored in these plastids
• Cell walls made of cellulose
• Includes
• several thousand green algae
• Several hundred thousand land plants

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Plant Taxonomy

• Kingdom
• Phylum/Division (-phyta)
• Class (-opsida)
• Order (-alies)
• Family (-aceae)
• Genus species
• Other less specific endings
• -phyte, -opsids, etc.
• Avoid common names!

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Green PlantPhylogeny
Embryophytes

• Embryophytes
• Bryophytes (not covered in class)
• Lycophytes
• Clubmosses and allies
• Euphylophytes
• Monilophytes
• Ferns and fern allies)
• Lignophytes
• Seed plants

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• Embryophytes
• Bryophytes (not covered in class)
• Lycophytes
• Clubmosses and allies
• Euphylophytes
• Monilophytes
• Ferns and fern allies)
• Lignophytes
• Seed plants

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Time for questions!

• What is meiosis? Mitosis?
• How do plants differ from animals?
• What is alternation of generations?
• In what Super-kingdom do plants belong?
• When did plants evolve?
• What is a plant anyway?!
• What are Embryophytes?
• How are these subdivided?

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Bryophyta

• Paraphyletic grade at base of Euphyllophytes
• Classes Bryopsida, Hepatopsida, Anthocerotopsida
• Dominant gametophyte generation
• non-vascular plants
• Without lignified tracheids
• 20,000 species!

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Lycophyta

• Embryophytes Tracheophytes Lycophytes sister
  to Euphylophytes
• vascular plants
• Dominant sporophyte generation
• 12-17/1300
• Microphylls, bi-flagellate sperm dichotomous
  branching
• Most diverse during the Carboniferous Period

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Lycopodiaceae
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Lycopodiaceae
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Selaginellaceae
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Selaginellaceae
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Isoetaceae
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Isoetaceae
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Monilophytes - ferns and fern allies

• MONILOPHYTES ferns and fern allies
• (L. monili, necklace L. forma, shape)
• Extant Groups ?/11500
• Phylogenetic placement Euphylolophytes sister
  clade to the Lignophytes (seed plants) taxonomic
  ranking at this level is variable by author.
  According to Kenrick and Crane (1997) Division
  Euphyllophyta (sister to Lycophyta)
  Infradivision Moniliformopses.
• Ecology and Distribution varied morphologically
  herbaceous, shrubs, trees, rhizomatous etc.
  cosmopolitan.
• Key Characters common vasculature protoxylem
  confined to lobes of the xylem strand.

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Monilophytes - ferns and fern allies