This study was carried out in the context of formative assessment where assessment and learning were integrated to enhance both teaching and learning. The purpose of the study was to: (a) identify pupils' ideas about biological inheritance through the use of a concept cartoon, pupils' drawings and talk, and (b) devise scaffolding structures that could be used together with the concept cartoon to support pupils in articulating their ideas about concepts associated with inheritance. The study was conducted in a primary 5 class (ages 10-11) in Singapore and pupils worked in small groups to discuss the opposing views posed by the characters in the concept cartoon. Scaffolding tools were used to guide pupils' discussions and to encourage pupils to evaluate, challenge, and document their own and their peers' ideas. A number of alternative conceptions were diagnosed through pupils' oral and written discourse, and students' questions and assertions had formative potential as they drew upon each others' ideas. By designing a formative learning environment, the teacher not only monitored pupils' thinking but also engaged the pupils in active learning. (Contains 4 figures.)