This study verified the efficacy of concept and vee mapping heuristics under cooperative (CP), cooperative–competitive (CP-CM) and individualistic whole (IW) class learning conditions in improving students' achievement in ecology and genetics. A total of 808 tenth-grade students were involved in the study. The results showed that the experimental groups taught with concept and vee mappings under the three learning modes achieved significantly better than the control groups. Students in the CP-CM condition in all groups achieved significantly better than their counterparts in the other two groups, whereas the CP-CM experimental group students achieved significantly best. A significant interaction between treatment and ability suggested that an element of competition, when combined with small group cooperation, favored students of lower ability.