Integrative Mapping of Global-Scale Processes and Patterns on "Imaginary Earth" Continental Geometries: A Teaching Tool in an Earth History Course

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ABSTRACT

The complexity and interrelatedness of aspects of the geosciences is an important concept to convey in an undergraduate geoscience curriculum. A synthesis capstone project has served to integrate pattern-based learning of an introductory Earth History course into an active and process-based exercise in hypothesis production. In this exercise, students are given (1) an imaginary global continental configuration and (2) a general categorization of the global climate. Students then work through cause/effect relationships in Earth processes and hypothesize global biotic and abiotic patterns to be mapped upon the imaginary continental framework. Presentation and discussion of each student's imaginary earth and his/her interpretation of the various mappable parameters engages students in each other's reasoning and creative thought processes while promoting group learning and increasing science communication skills. Examination of the evidence and procedures used in the retrodiction of actual global paleogeographic scenarios is then placed in the context of this project. In practice, students have responded enthusiastically to the opportunity to develop geographic interpretations of an imaginary paleogeographic framework using their understanding of modern Earth systems. Upon exit evaluation, greater than 85% of the students taking part in the exercise felt more confident in their ability to hypothesize patterns from process.

INTRODUCTION

Retrodiction is a scientific exercise commonly used in the earth sciences where one tests hypotheses of the past influence of a causal mechanism using independent observations of former patterns and/or related processes (Kitts, 1978). A central theme in geoscience research is the retrodiction of global patterns based on the character of present-day, observed patterns and processes. Many "paleo-" disciplines including those of paleoclimatology, paleobiology, paleogeography, and paleoceanography utilize this method. The practice of projecting physical and biological processes that we observe today back into the past, either to explain patterns recorded in the rock record or to hypothesize patterns that have not been preserved, is essential for developing an understanding of the environmental history of the Earth (Ziegler, 1990; Gyllenhaal et al., 1991; Rees et al., 2002). We are, after all, quite reliant on our understanding of today's world in order to understand Earth systems throughout deep time.

Introductory undergraduate courses in Earth history are, by nature, interdisciplinary. Recent texts (e.g. Stanley, 1999) and exercises (e.g. Bykerk-Kauffman, 1989; Zaprowski and Qyde, 1999) emphasize the systems aspects of Earth History and how investigation into this branch of the science is conducted. By covering more integrative topics, such as paleo-atmospheric composition modeling and general circulation models (GCMs), in addition to more traditional topics, such as biogeography, plate tectonics, and paleogeography, students begin to understand not only historical patterns but also our inferences concerning the processes that have shaped Earth history. Here, I present an active-learning exercise designed to serve as the capstone project to an undergraduate course in Earth History that embraces this process-based philosophy. The project integrates Earth system patterns and processes covered in lecture with the developing spatiotemporal intuition of students. It also fosters constructive interaction and discussion among participants, each with his/her own unique geographic and climatic parameters as a project framework. Although this exercise is designed for an introductory- to intermediate-level Earth History course, the model could also be employed in Earth System Science or Physical Geology courses.

BACKGROUND

The project was assigned to 14-20 students in introductory level (i.e. predominantly first- and second-year students) Earth History laboratory sections over three years at the University of Chicago (Chicago, IL) and one year at Lafayette College (Easton, PA). …