Eukaryotes

  1. Origin of Eukaryotes
    • -some question the endosymbiotic origin (aka fusion hypothesis) as the main driver behind it
    • -evidence from the PVC superphylum (superphyla of bacteria), which shares many features w/ Eukarya (and not necessarily w/ Archaea)
    • -therefore this superphyla may have served as
    • ancestrial "stock"
    • -& the evolution of the many major features of
    • Eukarya may have been present in some Bacteria
    • & evolved in steps
  2. Essential role of Prokaryotes
    • 1. Decomposers
    • 2. Symbiotic relationships (mutualistic)
    • ex: 500-1000 species in our intestines that help w/
    • digestion
  3. Prokaryotes Impact On Humans (Bad)
    • 1. 1/2 of all human parasites are bacteria (deadliness caused by toxins)
    • 2. Can be used as bioterrorism agents (ex: anthrax)
    • 3. Difficult to defeat given rapid evolution
  4. Prokaryotes Impact on Humans (Good)
    • 1. Fermentation for food
    • 2. Research
    • 3. Genetic modification & bioengineering
    • 4. Bioremediation-remove pollutants from the environment (ex: oil spill in Gilf of Mexico)
    • 5. Decomposers
    • 6. Mutualistic symbiosis
    • 7. Provide scenic landscapes
    • 8. Oxygenation of the Earth
  5. Protists (Eukarya 2.1 bya origin)

    General Characteristics
    • -mainly unicellular
    • -mainly aquatic
    • -some asexual, some sexual, some both
    • -they are all Eukaryotes
  6. Protists-Origins: Why so diverse?
    Endosymbiosis (process of engulfing cells that become endosymbionts & ultimately organelles/plastids)
  7. Primary Endosymbiosis
    One heterotrophic Eukaryote engulfs a photosynthetic cyanobacterium
  8. Secondary Endosymbiosis
    Red or green algae being engulfed by another Eukaryote
  9. Diplomonadida (Giardia) & Parabasalas (Trichomonas)
    • -Lack plastids
    • -Mitochondria lack DNA
  10. Euglenozoans
    Spiral or crystalline rod at base of flagella

    • A) Kinetoplastids (Trypanosoma)
    • B) Euglenids (Eugela)
    • -Photosynthesis or be heterotrophs
  11. Alveolates & Stramenopilans
    Red algae symbiont
  12. Alveolata
    Membrane bound sacs just under plasma membrane (unknown function)

    ex: Dinoflagellates, Apicomplexans (Plasmodium-malaria), Cilliates (Paramecium)
  13. Stramenopilans
    • Hairy flagellum and smooth flagellum
    • ex: Oomycetes, Golden Algae, Diatoms, Brown Algae
  14. Stramenopilans
    1. Brown Algae & "Seaweed"
    • -seaweed = some type of algae that have specialized tissues & "organs" like those seen in plants, but they have evolved independently
    • ex: Alternation of generations
    • Multicellularity & Tissue formation
    • Larger in size w/ parts (holdfast, stipe, blades)
  15. Cercozoans & Radiolarians
    Move by threadlike psuedopodia

    • A) Cercozoans (Forams-CaCO3 shells)
    • B) Radiolarians (SiO2 shells)
  16. Amoebozoans
    • -amoebas w/ lobe shaped psuedopodia
    • -these are thought to be the closest relative to the Fungi & Anamalia

    ex: Gymnoamoebans, enamoebans & slime molds
  17. Rhodophyta (Red Algae)
    Chlorophyta
    Charophyta
    • -Chlorophyll a
    • -endosymbiotic event w/ a cyanobacterium--->led to chloroplasts
  18. Rhodophyta (Red Algae)
    • -phycobillins
    • -some "seaweeds"
  19. Green Algae (Chlorophyta & Charophyta)
    • -Carotenoids
    • -Chlorophyll b
    • i. chlorophyta
    • ii. charophyta (stoneworts)
    • -sister group to plants
  20. Synapomorphies Charophyta share w/ Plants
    • 1. Similar percentage of cellulose in their cell walls
    • 2. Peroxisome enzymes that minimize loss of organic
    • products
    • 3. Similar structure to their flagellated sperm
    • 4. Similar chloroplast DNA
    • 5. Formation of phragmoplast (scaffold for formation
    • of the cell plate at the end of a miotic division
Author
Anonymous
ID
69769
Card Set
Eukaryotes
Description
biology
Updated