Geologic Time Scale Concept Sketch
ESC1000C Geologic Time Scale Concept Sketch
For this activity, you will be reviewing the geological time scale in the module reading
assignment from the Geological Time chapter in the PRI Digital Atlas of Ancient Life –
online textbook and the Earth History chapter from the OER Commons Earth Science
Textbook. Use the images of the geologic time scales in your readings to help you make
your Geologic Time Scale concept sketch. 50 points
Sketch and label a geologic time scale. Include dates of the following events in Earth
History on your time scale in the appropriate time period (you may have to look these up on
the internet but most are listed in your readings).
 First appearance of free oxygen in the atmosphere
 Earliest fossils
 Oldest animal fossils
 Great Dying Extinction (worst mass extinction at end of the Permian Period) – also
explain possible causes of this extinction

Archaeopteryx sp. appeared
 First Flowering Plants

Tyrannosaurus rex appeared
 K-T Extinction event (Dinosaurs died out) – also explain possible causes of this
 Last Ice Age began
 First
Homo Sapiens appear
Remember, detail is key. The causes of the two extinctions can be
listed below your diagram with explanations. Upload your concept
sketch to the drop box provided.