We live in a scientific society. Science is all around us. We take scientific principles for granted every time we use technology, such as a car, a computer, or a cell phone. Paradoxically, the scientific literacy of the population is minimal at best. Having a basic knowledge of scientific principles is no longer a luxury but, in today's complex world, a necessity. To increase the scientific literacy of non-science majors, an astrobiology course was developed at the Center for Science and Mathematics Education at The University of Texas at Austin. The course subscribes to an educational philosophy that promotes the significance of teaching science to non-science majors, endorses the importance of multidisciplinary content knowledge, supports the teaching of the nature of science in an implicitly mode, advances the discussion of socio-scientific issues, and includes competent thinking-based teaching strategies using the dynamic discipline of astrobiology. The thesis reviews the problems in scientific literacy, outlines the characteristics of this innovative course, proposes a novel standard - competent thinking - to evaluate scientific literacy and analyzes the results of this course in terms of competent thinking. Data collected provided evidence of an increase of competent thinking skills among the students, especially in terms of self-reflection. Both the first and the second pilot study showed strong evidence that students transitioned from naive to competent thinking arguments. The main study demonstrated that students greatly improve their self-reflecting skills. The final study confirmed improvement in terms of self-reflecting skills, and showed that students gradually improve their arguments based on logic, reason, sophistication, and evidences. Therefore, the results show that this innovative astrobiology course is an effective tool for enhancing competent thinking skills among non-science major students. / text