Seeds

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Seeds

• What terrestrial adaptations led to the success
  of seed plants?
• Gametophyte generation is even more reduced!
• Why hasnt the gametophyte generation been
  erased?
• Allele screening can occur in gametophytes since
  they are haploid
• Sporophyte embryos depend on female gametophyte
  for food

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• Spores in brypohytes and mosses resist
  environmental changes
• Seeds replace spores role of dispersing the
  species.
• Spores are retained within the sporangia
• Pollen frees sperm from water

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Gymnosperms

• What does gymnospem mean?
• Naked seeds
• How are the needle shaped leaves of Coniferophyta
  adapted to dry conditions?
• Thicker cuticle, stomata in pits

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Coniferophyta Examples
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Sequoia
Douglas Fir
Juniper
Cypress
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Pine ovulate cone
ovules
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Ovule from ovulate cone
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Pine staminate cone
Pollen
Pollen sac
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Germinating pollen grains
Pollen grains
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Seed Dispersal in Coniferophyta
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Hypothetical phylogeny of Seed Plants
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