Geosciences emphasizes the application of general principles of geology, geochemistry, cosmochemistry, and geophysics to problems in the marine and terrestrial environments of the Earth and to other planetary bodies. Graduate students routinely participate in expeditions at sea and on land and many doctoral theses evolve from these experiences. Students admitted to Geosciences of the Earth, Oceans, and Planets (GEO) are assigned an adviser, who is the chair of their three-person guidance committee. Based on the student's interests and the major affiliation of the adviser, students are assigned to a curricular group upon admission. Although students may change curricular groups in the course of the year, they must choose which departmental exam they will take.