Abstract. Drawing -based modeling as learning approach, it allows students to create models based on drawing which help them to run a simulation. Students can use drawing-based modeling to learn a pair of interacting population known as predato-prey system while they usually conducted practicum using diagram of organisms. This study was to explore students' argumentation and students' understanding on the concept of the ecosystem. The study was conducted quasiexperimental using the matching -only post-test -only control group design. The