Geological Time Line These questions are based on the Discovery Channel Online, http://www.discovery.com/exp/earthjourneys/timeline/timeline.html. Please refer to this site if you want to check your answer before submitting the quiz to be graded.
1.	Based on your reading, how old is the earth? 2,000 years 5,000,000 years 4,566,000 years 4,000,000 years
2.	What happened about 3.9 billionn years ago? major meteorite impacts start continental crust forms continental crust is destroyed major meteorite impacts, which appear once in a while, stop
3.	When did cyanobacteria first appear? 3.0 billion years ago 2.5 billion years ago 3.5 billion years ago 4.0 billion years ago
4.	When did plate tectonics begin? Pre-Cambian era Paleozoic era Mesozoic era Cenozoic era
5.	How did oxygen accumulate in the earth's atmosphere? it already existed by water it didn't stromatolites and photosythesis
6.	What percentage of all species was wiped out during the Ordovician-Silurian mass extinction? 50% 80% 85% 90%
7.	What was Pangea? myth mirage supercontinent mirage
8.	What was the cause of the Permo-Triassic extinction? dinosaur attack a dramatic, worldwide climate change flooding no one has formed a hypothesis
9.	When did the dinosaurs rule the earth? 700 to 300 million years ago 300 to 250 million years ago 205 to 65 million years ago 65 million years ago to the present
10.	Which is NOT a geological time period? Pre-Cambian era Mesozoic era Turneroic era Mesozoic era