M1:T5: EVOLUTION

• what were the conditions for early earth

  energy conditions:

  • radiation
  • volcanic action
  • metorite impacts
  • radioacitivity
  • no oxygen but carbon dioxide, nitrogen, carbon monoxide, hydrogen, amonia
• how did life come about

  • stanley miller
  • coming together of pre-biotic compounds
  • molecules chemically synth in high energy and reducing atm
• rna theory 


  1st self-replicating organisms
• early cellular process on earth

  hyperthermal chemoli respiration due to hydrothermal vents and lack of oxygen
• subsrface origin hypo


  subsurface is less hostile due to abundant energy and stable conditions
• earliest life form

  1. prokaryotes <—extremophiles
• what does eukayotes require

  20% oxygen due to Cyanobacteria
• Cyanobacteria 


  created conditions for 1st oxygenic photosynthesis
• micro-organisms 


  organims with typically cellular features too small to be seen without a microscope
• key events

  • life 3.86 billion
  • cyanobactria —> oxygenaction: 3 billion
  • euaryotic: 2 billion
  • atm oxy: 1 billion
  • multi cell: 650 million
• endosymbiotic hypo


  development of organelles in eukaryotes like mito
• chronometer 


  Measures changes in organisms over long periods of time

  • gene sequences
  • fossiled remians
• 2 types of Endosymbiotic theories

  1. serial: nucleus formed before mito and chloroplast
  2. symbiogensis: intracellular ass, nucleus after mito
• stramatolites


  fossiled microbial mat consist of layer of filamentous pro and trapped seeds
• 3 Astor biological things

  1. origin of life
  2. we are alone
  3. future of life
• different biosignatures

  1. sign of life
  2. object requires bio agent
  3. based on biomarkers
  4. 3 types: metabolic oxygen, structural and moleuclar