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In this two-part activity, which uses discovery and an inquiry approach, the participants will be given cartoon drawings representing significant events in the history of the Earth and asked to place them on a timeline made of colored ribbon. Then they mathematically relate the geologic time scale to a yearly calendar. After the calculations, they return to the timeline to reassess the placement of the events.

Intended Audience

9-12 X


Learning Objectives

By completing this activity, the student will be able to:
  1. Identify significant events in microbial evolution
  2. Translate information from one mathematical scale to another
  3. Understand the perennial dominance of microbes, past and present
  4. Understand the order of key events in evolution relating to microbes
  5. Gain an appreciation about the place of microbes in earth's history
Necessary Student Background


Students need mathematical (algebraic) skills, know how to use a calculator, and have some knowledge about the geological history of Earth.


Earth history, microbial evolution, historical events, time scales.

Print a PDF of this activity

Earth History: Time Flies, No Matter What the Scale (24 pages)