Paleo Enu Pt2

• Shared features of all mass extinctions


  • Many species became extinct, perhaps more than 30% of plants and animals of the time
  • The extinct organisms spanned broad range of ecologies, and typically include marine and non-marine forms, plants and animals, microscopic and large forms
  • The extinction were worldwide covering most continents and ocean basins
  • The extinction all happened within a relatively short time and hence relate to a single cause, or cluster of interlinked causes
  • The level of extinction stands out as considerably higher than the background of extinction level
• Form of fossils

  • The only evidence we have in fossils for identifying species and wider relationships to reconstruct the tree of life
  • Can tell us about behavior and ecology
  • Informs us about evolution (through variations in form)
• Consequence of multicellularity

  • Allowed plants and animals to become large
  • Cells could specialize within organism, some being adapted for feeding, others for reproduction, defense or communication