Using Earth History to Teach the Central Themes of Science

This material was originally created for Starting Point:Introductory Geology
and is replicated here as part of the SERC Pedagogic Service.

Initial Publication Date: December 2, 2005

By these researches into the state of the earth and its inhabitants at former periods, we acquire a more perfect knowledge of its present condition and more comprehensive views concerning the laws now governing its animate and inanimate productions.

- Charles Lyell, Principles of Geology, 1830-33
Fossilized fern fronds

An Earth history approach is necessary to understand certain of the big ideas of science: particularly evolution, plate tectonics, and climate change. These big ideas in turn are important not only for defining and uniting whole disciplines, but are at the heart of scientific issues which concern the modern public, including environmental issues, the search for extraterrestrial life, and preparation for catastrophes like earthquakes.

Modern observations of sea-floor spreading and shifts in gene pools are not enough to explain the way the Earth and its biosphere work. An Earth history perspective is necessary to explain the relationship between these forces as we have briefly observed them so far, and their more impressive effects, such as the structure of the Rocky Mountains or the evolution of the current diversity of life from a single ancestor.

  • Evolution: Central to the biological sciences. A combination of information from fossil sequences and genetic variations among living species provides us with the "tree of life" picture of the relationships among all organisms.
  • Plate Tectonics: Central concept of the geological sciences. Earth's plates have shifted at most a few meters since the mid-oceanic ridges were discovered, but paleomagnetic records and patterns in fossil and rock distribution can be combined to reconstruct past positions of continents.
  • Climate Change: Driving force behind Earth system science and other interdisciplinary initiatives. Only recently have most nations assembled adequate climate records (requires a 30+-year record of weather observations), so changes must be deduced from geologic clues.

Other Possibilities

The list above is by no means exhaustive, nor are the topic lists for each concept. Courses are also written to teach the principles of stratigraphy, biogeochemical cycling, weathering, etc.