Teaching digestive system: Spanish pre-service teacher’s learning difficulties and alternative conceptions

The aim of the research was to analyze the learning difficulties and alternative conceptions that Spanish pre-service teachers have about digestive physiology and anatomy. The study was conducted on a primary education bachelor’s degree biology course during the 2021/2022 academic year (n=91). The participants were asked to complete a conceptual test before (pre-test) and after the instruction (post-test). The results revealed that they had a limited knowledge of the digestive process before instruction (pre-test), especially those in the humanities baccalaureate group. Numerous alternative conceptions were identified, for example, that digestion ends in the stomach, mechanical digestion takes place only in the mouth, and nutrient absorption and transport into the bloodstream are not part of the digestive process. The results also indicated that levels of knowledge increased significantly after the course was completed (post-test); however, several features of the digestive process remained poorly understood, mainly because of the pre-service teachers’ lack of understanding of the cellular or molecular aspects that govern this process and their inability to distinguish between macro and micro levels of digestion. It is therefore recommended that the pre-service teachers acquire a comprehensive knowledge of the digestive by studying other scientific disciplines (physics, chemistry, cell and molecular biology, and so on).