ESCI Exam 2 Part 2

  1. Warm Little Pond Theory
    Uri Miller - simulated early earth environment (methane, ammonia, hydrogen) formed amino acids
  2. Volcanic Underground Theory (Hydrothermal Theory)
    life that can surive in extreme environments, high temperatures, anaerobic, no sunlight, lived off chemicals
  3. Colonisation Theory
    life arrived on a meteorite -ALH84001 - possible microfossils- carbonate globules (found only in organisms) - Mars -stratigraphy and precipitation indicate hydroactivity
  4. Prokaryotes
    first organisms, appeared 3.5 ya, <10 microns, DNA loose in cytoplasm, no nucleus and organelles, reproduce via fission (cloning), have not evolved, no variation
  5. Eukaryotes
    2.5 yo, >10 microns, DNA bound in chromosomes, have nucleus and organelles, reproduction involves recombination, variation
  6. Endosymbiotic theory- origin of eukaryotes
    • One prokaryote partially consumed another - evolves into eukaryote
    • Evidence - organelles have their own DNA and 2 membranes
  7. Earliest known fossils
    • Warrawoona, Australia 3.5 Ga - Stromolites - soft bodied, accretionary structure, growth layers single cells tied together
    • Common in Pre-Cambrian
  8. Acritarchs
    • 1.8 Ga
    • secrete proteinacious cyst
  9. Ediacaran fauna
    Earliest Metazoans (late Pre-Cambrian) - soft bodies not preserved, impressions in sandstone. Similar body structures to later fossils
  10. Burgess Shale
    In BC, Canada - MidCambrian explosion- hard bodies, fossils easily preserved in a low oxygen environment - Shows a rapid diversification of shapes and taxa, some unique to own phyla- first appearance of fauna (Chengjiang has similar fauna)
  11. Darwin's gradualism
    increasing cone of complexity, diversification from one source, slow gradual change (later too much competition for unique new life)
  12. Punctuated Equilibrium
    periods of evolutionary inactivity, then extinction at times of drastic environmental change, rapid biological change
  13. Decimation and Diversification
    high degree of diversity in the past, many forms died out, only few continued to evolve
Card Set
ESCI Exam 2 Part 2
Orgins of life, earth history