Abstract
While interdisciplinary collaboration is desired among researchers, traditional science instruction generally results in science disciplines being taught as separate entities. This study focuses on student understanding of concepts at the intersection of two isolated disciplines-geoscience and bioscience-across two purposeful samples of college-aged students (United States, Germany). Specifically, we explored: 1) how students conceptualize large-scale biologic and geologic changes on Earth over deep time; 2) the relationship between student's conceptions and their understanding of evolutionary and geologic theories; and 3) how those conceptualizations explicate the need for integration of concepts within school curricula. Students were asked to respond to items about seven major evolutionary events in Earth's history (biosciences) and perceived changes to Earth's size and continental positions over time (geosciences). Both groups exhibited difficulties understanding absolute ages in deep time, although Young Earth and Young Life perspectives were present in the U.S. group and absent in the German group. Conceptions about changes to Earth's size and continental positions over time were consistent across both groups. Findings highlight the need for scientific education instruction in both countries that is interdisciplinary in content.