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

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