Evolution of Eukaryotes/Plants

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Evolution of Eukaryotes/Plants
2012-02-20 19:04:45
Biology Evolution

Eukaryotic Diversity is Ancient
Show Answers:

  1. What is a Eukaryote?
    A eukaryote is membrane bound, has compartmentalisation, organelles, and a membrane bound nucleus.
  2. What was the key to eukaryotic innovation?
    The nuclear envelope
  3. What is the Endosymbiosis Theory?
    The Endosymbiosis Theory was explored by Lynn Margulis 30+ years ago. The idea she promoted was that the mitochondria was a bacterium that had been incorporated into an ancient eukaryotic history/lineage (Mutualism).
  4. Support for Endosymbiosis
    • Mitochondria :
    • are similar in size to bacteria
    • reproduce by fission
    • circular genome
    • have own ribosomes
    • translate proteins
    • have a double membrane system
  5. Does endosymbiosis explain eukaryotes having chloroplasts too?
    • Yes. Why?
    • 1. Not all eukaryotes have them
    • 2. In some groups of photosynthetic protists, there was a secondary endosymbiosis
  6. Where did secondary endosymbiosis first occur?
    Secondary endosymbiosis first occured in green algae.
  7. Land plants are important because...
    • main primary producers
    • affect atmospheric gases
    • stabilize soil conditions
    • moderate local climate
  8. Tradition plant classification
    nonvascular, seedless vascular and seed plants
  9. Examples of non vascular plants are:
    liverworts, hornworts and mosses
  10. Characteristics of non vascular plants are:
    • All non-vascular plants have a cuticle
    • Liverworts have simple pores and protected embryos
    • Hornworts and Mosses also have stomata
  11. Examples of seedless vascular plants are:
    lycophytes, ferns and horsetails
  12. Characteristics of seedless vascular plants are:
    • All: Trachieds and roots
    • Lycophytes: addition of vascular tissue
    • Horsetails and Ferns: true leaves
  13. Examples of seed plants are:
    angiosperms and gymnosperms (conifers, cycads, gnetophytesm ginko)
  14. Characteristics of seed plants are:
  15. Benefits of seeds and pollen are:
    • Can tolerate drying
    • Seeds are packaged with nutrients
    • Not dependent on parent during fertilzation
    • Heterospory: male and female parts/sporophye
  16. Barriers for plants making the move to land were:
    • water loss
    • gas exchange
    • reproduction
    • water and nutrients equisition and movement
  17. Solution for water loss:
    Cuticle: a waxy protective layer
  18. Solution for gas exchange:
    • First there were pores: openings in the cuticle
    • Then there were stomata: pores with control (guard cells)
  19. Solution to reproduction barrier:
    "Protected embryos": seeds
  20. What is the process of Alternation of Generations:
    • Start: Gametophyte(multicellular haploid organism) n
    • Mitosis
    • Fertilization
    • Mitosis
    • Sporophyte(multicellular diploid organism) 2n
    • Meiosis
    • End: Mitosis (n)
  21. Solution for water and nutrient equisition and movement:
    • Vascular tissue: xylem and phloem
    • Roots
  22. Gymnosperms vs. Angiosperms
    • Angiosperms have:
    • triploid endosperm (double fertilization:2 male gametes/3 sets of chromosomes)
    • flowers: DIVERSIFICATION