‘The brain needs nutrition’: pupils’ connections between organizational levels

Previous research suggests that connecting organizational levels of biological systems is challenging for pupils. In the present study we investigated 122 pupils’ written responses to a question in a national biology test concerning how nutrient molecules are adsorbed by the small intestine and transported to the brain. We aimed to investigate what awareness the pupils have of the connection between the digestive and circulatory systems. We mapped the pupil’s expressed knowledge by using content analysis which was performed in five steps including connection between the systems, organizational levels and scientific explanations. We found that the most correct descriptions contained the highest number of connections between the digestive and the circulatory systems and linking of the different organizational levels. The most correct descriptions included the highest proportion of the meso level. Therefore, knowledge at the meso level seems to be essential for grasping connections between macroand submicro-level processes, and connections of digestion and circulation systems.