CHAPTER 30 PLANT DIVERSITY II

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CHAPTER 30PLANT DIVERSITY II

• I. Major Seed Plant Adaptations
• A. gametophyte is very tiny and retained within
  the body of the sporophyte
• B. seed replaced the spore as the main means of
  offspring dispersal
• C. pollen carries the sperm which usually are
  not flagellated

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II. 11 Plant Divisions (cont.)

• G. Division Coniferophyta (conifers) - naked
  seeds not enclosed in a fruit gametophyte
  clustered in cones most are evergreens many
  with needles
• H. Division Cycadophyta (cycads)
• I. Division Ginkophyta (ginko tree) - is
  deciduous
• J. Division Gnetophyta - Ephydra exhibits
  double fertilization (most closely related to
  flowering plants)

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Plant Divisions (cont.)

• K. Division Anthophyta (flowering plants) -
  most diverse widespread of the plants xylem
  more specialized (tracheids gave rise to vessel
  elements) gametophyte contained within a
  flower (modified leaves) which often serves to
  attract pollinators seed develops within the
  ovary which becomes the fruit (aids in seed
  protection dispersal) double fertilization
  occurs

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III. Ecological Significance

• A. base of terrestrial food chains
• B. define the habitat of a community
• C. coevolution of plants and animals
• D. altered climate by reducing carbon dioxide
  levels cooling effect
• E. agriculture
• F. products like lumber, drugs, fibers, etc.