A REVISION OF HISTORICAL GEOLOGY

Traditionally historical geology textbooks are organized with a long section on the principles used to understand Earth history, followed by the history. The philosophy is that in order to understand the history of Earth one first needs to know how that history was deciphered. However, assessment of students work indicates that students frequently do not make the connection between the principles and the history. If prompted with a reminder, students struggle to apply Principles studied early in the course to the history studied later in the course.

In our revision of the course we decided to build the course around what we called "Big Ideas and Understandings." The big ideas include: 1. Science is based on evidence; 2. Earth has a long history; 3. Earth has changed through time; and 4. The history of Earth is recorded in the sedimentary archives. Each of these ideas and understandings are taught by looking at significant events in Earth's history. For each event the focus was on answering the questions: How do we know what we know? What is the evidence for this event? What are the changes that we observe? And, How do rocks tell the story? The events we chose to highlight include: the origin of Earth and life, Snowball Earth, evolution of the atmosphere, Rodinia, the Cambrian Explosion, emerging from the water, Pangea, extinctions, radiation, Cordilleran, mammal radiation, Paleocene-Eocene Thermal Maximum, hominid evolution and Pleistocene evolution. Activities that highlight the linkage between principles and history were developed or modified from existing labs.

When introduced to principles as needed to explain the history students are better able to make the connection between the two. About half of the activities and labs that we used in the past are still used, just in a different order and sometimes with just slight modification. For the most part, the new activities and labs worked out well, with only some modifications and/or additional material needed for the next time this course is taught.