1114 Chapter 17

  1. Terrestrial surface of Earth
    Lifeless for most of history
  2. Possible benefits of early life on land?
    • Unfiltered sunlight
    • Higher CO2 concentrations
    • Fewer herbivores and pathogens (during initial land colonization)
    • Nutrient rich soils
  3. Key adaptations to challenges and benefits of land distinguish major groups
    • Vascular tissue
    • Seeds
    • Flowers
  4. Bryophytes
    • Non-vascular plants (have no xylem and phloem)
    • Tend to be small and live in moist places
    • Ex: mosses, liverworts, hornworts
  5. Bryophytes vascular tissue
    • Tissue made up of cells that join to form tubes that transport water, nutrients, and sugars
    • Xylem and phloem
  6. Xylem
    • Dead tracheid or vessel element cells form tubes that transports water from root to shoot
    • Contain lignin: hard polymer that provides structural support for xylem
  7. Tracheids
    • Long, thin xylem cells
    • Image Upload 1
  8. Vessel element
    • Shorter, thicker xylem cells
    • Image Upload 2
  9. Phloem
    • Living sieve tube cells form tubes that transport sugar formed via photosynthesis from leaves to the rest of the plant
    • Image Upload 3
  10. Why would the lack of vascular tissue result in bryophytes being short?
    • They can't transport nutrients and water over long distances effectively
    • Lack of structural support from lignin in xylem cells
  11. Bryophytes Reproduction and limitations
    Sperm are flagellated. This requires water for fertilizaition
  12. Dispersal by spores
    Reproductive cells (single celled)
  13. Seedless Vascular Plants
    • Ferns 
    • Representative group=Pteridophytes
    • First plants to grow tall
  14. Seedless vascular plants
    Sperm is still flagellated and dispersed by spores (single celled)
  15. Gymnosperms and Angiosperms
    Seed plants
  16. Key differences between seed and seedless plants?
    • Ovules and pollen 
    • Seeds
  17. Ovule
    • Structure in which egg (female gamete) of plant is produced 
    • Has protective covering: integument
  18. Pollen grain
    • Contains male structures that produce sperm (male gamete of plants within a protective pollen wall
    • Sperm delivered to egg via pollen
    • Sperm is no longer flagellated and need water
  19. Benefits of pollen delivery of sperm over free flagellated sperm?
    • MUCH greater distribution potential over flagellated sperm
    • Doesn't require water for movement
    • Can be transported on animals or wind
    • Protective pollen wall prevents desiccation
  20. Seeds
    • Primary dispersal mechanism of seed plants
    • Diploid plant embryo + food supply + seed coat
  21. How does an ovule develop into a seed
    Initiated by pollination (transfer of pollen to portion of seed plant that contains ovules
  22. Pollen tube
    • Pollen grain grows this which releases sperm into the female portion where eggs are 
    • Fertilization of egg by sperm begins transition from ovule to seed
    • Image Upload 4
  23. Why is seed dispersal beneficial over spore dispersal in size?
    • Spore: usually single celled
    • Seed: multicellular embryo
  24. Why is seed dispersal beneficial over spore dispersal in protection post-dispersal from parent plant?
    • Spore: none
    • Seed: protective seed coat from integument
  25. Why is seed dispersal beneficial over spore dispersal in post-dispersal resource supply?
    • Spore: none
    • Seed: food supply
  26. Why is seed dispersal beneficial over spore dispersal in length of dormancy?
    • Spore: usually relatively short
    • Seed: up to hundreds of years (sometimes thousands)
  27. Gymnosperms
    • Bear "naked" seeds (aka not contained in fruit)
    • Seeds often form on cones: conifers= cone-bearing plants
  28. Gymnosperm Reproduction
    • Sperm no longer flagellated (contained within pollen grain)
    • Primary dispersal route: seeds
  29. Ovulate cones
    • Contain ovules and seeds
    • Larger (rigid structure)
  30. Pollen cones
    • Produce pollen
    • Smaller and not what is stereotypically seen
  31. How are gymnosperms pollinated?
    • Wind pollinated
    • No adaptations for pollinator attraction
    • Produce massive clouds of pollen
  32. Angiosperms
    • Seed plants with flowers and fruits
    • 90% of all plant species
    • Seeds "contained" in fruit as opposed to "naked" gymnosperm seeds without fruit
    • Sperm also contained in pollen grain and dispersal through seeds
  33. Flowers
    • Mode of sexual reproduction in angiosperms
    • Composed of 4 whorls of modified leaves
  34. Whorl
    Structures arranged in a circle
  35. 4 parts of a whorl
    • Sepal
    • Petals
    • Stamen
    • Carpel
  36. Sepal
    Sterile outermost whorl that protect flowers before opening
  37. Petals
    Sterile whorl often used in pollinator attraction
  38. Stamen
    • Male portion of the flower
    • Includes anther (site of pollen production) held up by filament
  39. Carpel/Pistil
    • Female portion of a flower
    • Sticky stigma=site of pollen deposition
    • Style: holds it up
    • Ovary containing ovule (produces eggs)
Card Set
1114 Chapter 17