History and Nature of Science enriched Problem-Based Learning on the origins of biodiversity and of continents and oceans

The episode of the History of Science (HOS) on the theory of continental drift proposed by Alfred Wegener has been considered an excellent example for teaching students aspects of Nature of Science (NOS) and the relation of Science with social and tecnological contexts. We implemented a NOS and HOS-enriched Problem-Based Learning environment at the middle (year 7 of the Portuguese National Curriculum) and secondary level (year 10) for teaching the origins of biodiversity and of continents and oceans (mobilism). The main objective of this study was to provide implementation practices to adress the lack of guidelines of how to use Problem-based learning (PBL) in classrooms for 12 to 16 year old students. This constitutes the first practical example of implementation using Wegener's episode of HOS for teaching geological mobilism integrated with evolution. Therefore, in this study, we provide specific suggestions for supporting teachers' classroom efforts in implementing PBL, such as the appropriate scaffolding. The ill-problem presented to students was based on the phylogeny of extant and extinct ratite birds, described by Charles Darwin and the present geographical distribution. The evaluation of the students was focused on the chain of reasoning employed, and we performed a comparisation analysis of the problem's solution presented by the students of both classes regarding the explanation of the phylogeny of ratites based on geological mobilism. We observed an overall improvement (25-77%) of the percentages of students pre- and post-instruction adequate answers; therefore our PBL strategy was efficient.