Ediacaran Period

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Ediacaran Period
2014-05-01 18:42:31

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  1. cells
    membrane encloses structures which control molecules entering and exiting as well as the chemical reactions within
  2. What do all cells need to live?
    energy and carbon based molecules
  3. autotroph
    fix their own carbon
  4. phototroph
    an autotroph that uses sunlight/photosynthesis to fix their own carbon
  5. chemotroph
    an autotroph that use chemical reactions to fix their own carbon
  6. heterotroph
    cannot fix their own carbon and must acquire it through ingestion
  7. The Precambrian makes up the first __ billion years of Earth's history
    4 (88.9% of Earth's history)
  8. Metazoan
    animals: multicellular heterotrophic eukaryotes
  9. poriferan
    • no/single tissue (no gastrulation)
    • assymetrical (e.g. sponges)
    • most primitive multicellular animal
    • sessile filter feeders (colonial or solitary)
    • bodies supported by spicules (made of either silica or calcite)
  10. cnidarians
    • 2 tissues "diploblastic"
    • radial symmetry
    • major reef builders
    • e.g. jellyfish, corals, anemones
  11. bilaterians
    • 3 tissues, "triploblastic," bilateral symmetry
    • e.g. vertebrates, molluscs, arthropods
  12. The fate of individual tissues come from the early development of
    germ layers (primary tissues)
  13. Tissues develop through the process of __
    gastrulation: During embryogenesis, cells differentiate into various tissues (germ layers)
  14. choanoflagellates
    • what poriferans evolved from
    • protista: collar cells similar to the collar cells in sponges
    • colonial or solitary
  15. germ layers of cnidarians
    • endoderm: forms inner body lining, gut, and digestive tissue (no through gut: food and waste enter/exit same hole)
    • ectoderm: forms outer body lining; contain "stinging cells" called nematocysts. Many are toxic.
  16. 2 life stages for cnidarians
    • polyp: benthic, sessile, colonial or solitary, reproduces asexually or sexually
    • medusa: pelagic, planktonic, reproduces sexually
    • Some go through the complete life cycle and some live one stage only.
  17. germ layers of bilaterians
    • endoderm: inner body lining with a through gut and digestive tissues and organs
    • ectoderm: protective outer body lining (epidermis), central nervous system
    • mesoderm: middle tissue: derivatives include circulatory system, muscles, and coelom
  18. coelom
    • fluid filled cavity which suspends and cushions organs
    • creates environment for organs to grow independent independent of body
    • acts as a hydrostatic skeleton: provides a structure for muscles to work against, which helps locomotion
  19. regulatory genes
    decides what piece should be built where and when
  20. structural genes
    genes that build
  21. hox genes
    • regulatory genes that identify with specific regions of the body
    • conservative: Hox genes in a fly will work in a mouse.
    • directly reflect revolutionary relationships (More derived animals have more hox genes.)
  22. Darwin's dilemma
    no fossils older than the Cambrian (540 mil years ago)
  23. significance of the Ediacara Biota
    • first microscopic "animals" on the planet
    • bilaterians?
    • first complex ecosystem
    • "pre" cambrian radiation
    • soft bodies
    • morphologically very diverse
    • evidence of "microbial" mats
    • oldest skeleton
  24. tubular constructional morphology
    • commonly occur in abundances that cover bedding planes
    • diverse types and sizes
    • at least in Ediacara strata are the most common discrete body fossil (by an order of magnitude)
  25. The Ediacaran period was __ mil years ago
  26. The Ediacara Biota was __ mil years ago