Section #: 21.1 The Geologic Time Scale

Practice Test
      
  1.What is at the bottom of the geologic time scale?  
  a.   the Silurian Period  
  b.   the Cenozoic Era  
  c.   the oldest division of time  
  d.   the youngest division of time  
  Hint    
      
  2.According to the figure, what marked the end of the Mesozoic Era?



 
  a.   the extinction of many marine invertebrates  
  b.   the extinction of the dinosaurs  
  c.   the building of the Appalachians ends  
  d.   mammals are abundant  
  Hint    
      
  3.What era of geologic time ended with the largest extinction event in Earth history?  
  a.   the Cenozoic  
  b.   the Cretaceous  
  c.   the Paleozoic  
  d.   the Mesozoic  
  Hint    
      
  4.What is the longest division of time in the geologic time scale?  
  a.   an epoch  
  b.   a period  
  c.   an era  
  d.   an eon  
  Hint    
      
  5.What is the shortest division of time in the geologic time scale?  
  a.   an epoch  
  b.   a period  
  c.   an era  
  d.   an eon  
  Hint    
      
  6.According to the table, which was the first significant event that involved life?

Table 1: EARTH HISTORY-SHAPING EVENTS

Origin of the solar system

Earth forms, 4.6 B.Y.B.P.

Oceans form, 4.0 B.Y.B.P

Primitive algae evolves, 3.3 B.Y.B.P

First fossil evidence of multicellular organisms, 1.2 B.Y.B.P.

Trilobites are abundant, algal reefs form, 600 M.Y.B.P.

First corals evolve, invertebrates dominate oceans, 500 M.Y.B.P.

First land plants evolve, insects appear, 440 M.Y.B.P.

Fishes are abundant, early amphibians evolve, 400 M.Y.B.P.

Forests that become coal swamps are present,300 M.Y.B.P.

Earliest reptiles evolve, 300 M.Y.B.P.

Alleghenian Orogeny occurs, 270 M.Y.B.P.

Trilobites become extinct, 270 M.Y.B.P.

Earliest dinosaurs appear, 225 M.Y.B.P.

Pangaea breaks up, 225 M.Y.B.P.

Earliest mammals evolve, 200 M.Y.B.P.

Dinosaurs are abundant, 180 M.Y.B.P.

The first birds evolve, 180 M.Y.B.P.

Asteroid impact, 66 M.Y.B.P.

Modern groups of mammals appear, 60 M.Y.B.P.

Earliest horses evolve, 60 M.Y.B.P.

Large mammals evolve, 40 M.Y.B.P.

Carnivores abundant, 11 M.Y.B.P.

Adirondack mountains uplifted, 11 M.Y.B.P.

First humanoids evolve (Australopithecus africanus), 3 M.Y.B.P.

Ice Age of the Pleistocene begins, 1 M.Y.B.P.

Mammoths and mastodons are abundant, 1 M.Y.B.P.

Large ice sheets retreat ~ 10 000 years ago

Mount Vesuvius erupts and destroys Pompeii, A.D.79

New Madrid Earthquake, 1811-1812

Chicago Fire 1871

Krakatoa eruption in Java, 1883

Chicago Bull win 5th World Championship, 1997



 
  a.   origin of the solar system  
  b.   Earth forms  
  c.   oceans form  
  d.   primitive algae evolves  
  Hint    
      
  7.What marks the end of the Proterozoic Eon?  
  a.   the first appearance of organisms with hard parts  
  b.   oxygen breathing organisms  
  c.   free oxygen  
  d.   mammals  
  Hint    
      
  8.What is the current era?  
  a.   Archean  
  b.   Cenozoic  
  c.   Mesozoic  
  d.   Paleozoic  
  Hint    

 
   
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