Lecture Ch. 29 Date _______

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Lecture Ch. 29 Date _______

• Plant Diversity I The Colonization
  of Land

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Plant Evolution

• bryophytes (mosses), pteridophytes (ferns),
  gymnosperms (pines and conifers) angiosperms
  (flowering plants)
• Plants multicellular, eukaryotic,
  photosynthetic autotrophs
• Terrestrial colonization
• Vascular tissue
• The seed
• The flower

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Nonvascular vs. Vascular plants

• Nonvascular-Bryophytes
• Vascular
• Pteridophytes
• Gymnosperms
• Angiosperms

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Plant origins

• Charophytes green algae (closest plant ancestor)
• Similarities
• 1-Homologous chloroplasts
  chlorophyll a b
• 2- Biochemical similarity cellulose composition
  peroxisomes
• 3- Cell division similarity mitosis cytokinesis
• 4- Sperm similarity ultrastructure
  
• 5- Genetic relationship nuclear genes rRNA

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Characteristics that separate plants from algae
ancestors

• Apical meristems localized regions of cell
  division
• Multicellular, dependent embryos (embryophytes)
• Alternation of generations
• Walled spores produced in sporangia
• Multicellular gametangia

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Other terrestrial adaptations

• Cuticle
• Stomata
• Xylem and phloem
• Secondary compounds

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Bryophytes

• Mosses, liverworts, and hornworts
• 1st to exhibit the embryonic condition (male
  antheridium female archegonium)
• Flagellated (water) sperm
• No vascular tissue (imbibe water)
• No lignin (short stature)
• Haploid gametophyte is the dominant generation

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Mosses
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Parts of a Moss Plant
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Three variations on gametophyte/sporophyte
relations

• Page 598 Bryophytes
• Sporophyte dependent on gametophyte
  Gametophyte-dominant life cycle, the dependent
  sporophyte is nourished by the gametophyte as it
  grows out of the archegonium

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Pteridophytes seedless vascular plants

• Ferns, club moss, horsetails
• True roots and leaves
• Roots have lignified vascular tissue
• Sporophyte-dominant life cycle
• Homosporous plants a single type of spore.
• Sporophyte----gtSingle type of spore
  ----gtBisexual gametophyte
  ----gtEggs sperm (flagellated damp locations)
• Carboniferous period plants

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Pteridophytes

• P. 598 Large sporophyte and small independent
  gametophyte (fern)
• Sporophyte is dominant generation
• Gametophyte is small, photosynthetic and
  free-living (not dependent on the sporophyte for
  their nutrition.

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Life Cycle of a Fern
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Fern Frond
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