How to Organize an Earth History Course or Unit

Earth history concepts such as geologic time can themselves be used to structure a course or unit and enable the instructor to emphasize the connections between the topics and the disciplines being taught.

• Geologic Timeline: in the chronologic order that the events happened, encourages emphasis of cause-and-effect relationships and the magnitude of geologic time. Often starts with a survey of the principles being discussed (like stratigraphy) and the evidence being used (radiometric dating).
• History of Science: as the geologic past was discovered and discussed by human beings. This framework adds a human element and stresses the whole process of science including how discovery and debate work and have worked over the years.
• Development of a Landscape: according to regional stratigraphy, which allows students to learn the principles of stratigraphy by actually applying them and allowing them direct contact with the evidence for the theories.
• Land, Life, and Climate Change: one discipline at a time: for example, geology, then biology, finally atmospheric science. Gradually show the students (or have them work out), the connections between continents, oceans, life, and air. This approach can be especially helpful to students with limited scientific background, as they can learn the basic terms and concepts for different sciences one at a time, then deal with the complications of systems thinking.

It may be best to break Earth history up and to focus on a particular time period of interest.

• Age of the Dinosaurs: a tight focus on a popular subject is one way to deal with the challenge of simply recruiting students. Once in class, they can be introduced to a broad variety of scientific topics and methods.
• The Precambrian: the first four billion years of Earth history are when all of the big changes took place which resulted in the modern Earth system. This course is a perfect opportunity to get students involved with the cutting edge of science, particularly astrobiology.

Other Possibilities

There are, of course, other logical ways to organize an Earth history course or unit. For example, it is possible to teach paleontology one lineage at a time, studying the brachiopods, then the bryozoans, then onto others.