Beginning with the Precambrian period, Earth’s past is a vast series of time-periods – chronological dating that relates geological strata to time. The geologic time scale (GTS) is used by geologists, paleontologists, and other Earth scientists to describe the timing and relationships of events that have occurred during Earth’s history. The Precambrian started with the origin of the earth about 4.5 billion years ago and ended 570 million years ago. The timeline is grouped into eons, eras, and periods (each successively smaller units of time).
Lesson 1 (or “Day 1”) Material
Lesson 2 (or “Day 2”) Material
- Day 2 Instructor Presentation
- Day 2 Student Handout
- Day 2 Rubric
- Read Earth 22 – Precambrian
- Read Earth 22 – Pangaea
- Read Earth 22 – Dinosaur
- Read Earth 22 – Geologic time scale
- Read Earth 22 – GSA Geologic time scale
Lesson 3 (or “Day 3”) Material
Lesson 4 (or “Day 4”) Material
12:07 A Brief History of Geologic Time
1:58 How To Make Pangaea | Geology Unit
4:04 Geologic “Eras”, animated
Compare Contrast and Debate
Background: Scientists use the expressions Eon, Era, Period, and Epoch to convey very long periods of time through shorter periods of time. This approach can be confusing at times – especially to students.
- Position A – The approach used, even though it can be confusing, is appropriate and meaningful.
- Position B – A simpler approach should be identified and used. This would help everyone – especially students.
Resources Documents and Links
Special Notes and Notices
- Science & Engineering Practice: Analyze and interpret data.
- Cross-Cutting Concept: Systems and System Models.