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[{"$nulls":5},"The Big Five Mass Extinctions"]
[]
["Life as we know it has been shaped and changed dramatically by mass extinction events.  Try"]
["to match up the geologic time periods when these extinctions occurred, place the periods in "]
["chronologic order, determine the duration of the extinction interval, and what percentage of "]
["marine invertebrate families (mifs) were wiped out as a result of the extinction."]
[]
["1)  The first (oldest) extinction event, which was not the late Triassic, was less in duration"]
[null," by 3 m.y., 2 m.y., and by 6 m.y., than the ones where ~15%, ~21% and ~57% of"]
[null,"mifs went extinct, in that order."]
["2)  The late Permian extinction, whose duration is greater than the event where ~15% of mifs"]
[null,"went extinct, occurred earlier than only the events that lost ~15% and ~20% mifs."]
["3)  The events that lost ~20% and ~22% mifs are the Ordovician and Triassic, in some order."]
["4)  The late Triassic event is not the most recent extinction to occur. "]
["5)  The late Devonian event that lost ~21% mifs occurred before the late Cretaceous extinction"]
[null,"and before at least one other extinction event."]
["6)  The event that had ~5 m.y. duration occurred more recently than the event with a duration"]
[null,"of ~4 m.y."]
[]
[{"$nulls":4},"% Extinction of",{"$nulls":4},"Approx. Duration",{"$nulls":4},"When Event"]
[{"$nulls":4},"Marine Invert. Families",{"$nulls":4},"of Event",{"$nulls":4},"Occurred"]
[null,null,"  ~15%","  ~20%","  ~21%","  ~22%","  ~57%","  ~2 million years","  ~4 million years","  ~5 million years","  ~8 million years","  ~17 million years","  most recent",null,null,null,"  oldest"]
[null,"late Cretaceous  "]
["Geologic","late Devonian  "]
["Time","late Ordovician  "]
["Period","late Permian  "]
[null,"late Triassic  "]
[null,"most recent  "]
["When"]
["Event"]
["Occurred"]
[null,"oldest  "]
[null,"~ 2 million years  "]
["Approx.","~4 million years  "]
["Duration","~5 million years  "]
["of Event","~8 million years  "]
[null,"~17 million years  "]
[]
["Order","     Extinction Event",null,"% Marine Invertebrate Families",{"$nulls":8},"Duration of Event"]
["youngest"]
[]
[]
[]
["oldest"]

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