Bellringer

1
Bellringer

• Thinking back to the last class period, one of
  the geologic eras had more asteroid impacts than
  the others.
• Name that era.
• Do you think this is because there were actually
  more impacts in this era of time, or could there
  be another reason?
• Justify your decision.

2
Time After Time (cont.)

• Today you will complete your timeline and post
  them in the hallway. In addition, you have some
  questions to answer about your timeline.
• Use the chart to mark the mass extinctions. You
  may choose any symbol you wish for mass
  extinctions, but be sure to provide a key.
• Finally, draw organisms that would be
  representative of the type found on the planet in
  each era. Be sure to include both plant and
  animal life.

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4
Time After Time Questions

• Compare the Precambrian Era to the rest of the
  time chart. What percentage of total geologic
  time does it represent?
• According to the data on your chart, what is the
  average length of time between mass extinctions?
• What is the average time between major impacts?
• Is there a correlation between major impacts and
  mass extinctions? If so, where on the timeline
  can you find a correlation?
• Is there a way to predict the year in which the
  next large impact might occur? Support your
  answer with facts from your time line.

5
Ticket Out

• What patterns do you see when you compare
  asteroid impacts and mass extinctions?
• What mass extinction might signal the end of the
  Cenozoic era (the era we are currently in)?