The rapid development of social media tools has drawn much research interest in teacher education. This development has suggested that a wiki with discussion (i.e., an enhanced wiki) seems valuable in facilitating online collaborative and interactive learning. This study examined dynamic patterns of revision behavior in group writing by distinguishing two forms of interaction, cooperation, and collaboration. We tried to explore the links between revision behaviors in group writing and the social construction of knowledge in online discussions. Data from 30 pre-service teachers in a wiki project that lasted for three months were analyzed by using content analysis with visual techniques. Results suggested that the dynamics of revision behavior have evidently moved from cooperation toward collaboration during group writing activities. Compared with the low-collaboration group, discussions of the high-collaboration group demonstrated a gradual pattern of knowledge construction and revealed more metacognitive and social interaction features. This study contributed to existing group learning research and also shed light on collaborative writing pedagogy.