GEOS 101
The Co-Evolution of Earth and Life Spring 2025
Division III
Cross-listed ENVI 105

Our planet is about 4.6 billion years old and has supported life for at least the last 3.5 billion of those years. This course will examine the relationship between Earth and the life that inhabits it, starting with the first living organisms and progressing to the interaction of our own species with the Earth today. Students will investigate the dynamic nature of the Earth-life system and learn about the dramatic changes that have occurred throughout the history of our planet. We will ask questions such as: How did the Earth facilitate biologic evolution, and what effects did those biologic events have on the physical Earth? When did photosynthesis evolve and how did this biological event lead to profound changes in the world’s oceans and atmospheres? How and why did animals evolve and what role did environmental change play in the radiation of animal life? How did the rise and spread of land plants affect world climate? How do plate tectonics, glaciation, and volcanism influence biodiversity and evolutionary innovation? What caused mass extinctions in the past and what can that teach us about our current extinction crisis? Labs will involve hands-on analysis of rocks, fossils, and real-world data as well as conceptual and analytical exercises; field trips will contextualize major events in Earth history and will help students learn to read the rock record. Through these investigations, the class will provide a comprehensive overview of Earth’s dynamic history.