The aim of this study was to determine the changes in the environmental perceptions of prospective science teachers after various environmental-related subjects and concepts included in the curriculum were covered, and at the end of a sensitive and cognitive acquisition period of three years. In the collection of the data, the Word Association Test (WAT), which included the key concept of 'environment', was utilized. Tests were applied to the students (55 subjects) twice, one of which was in the second class year, when they started taking Biology I and II, Biology Laboratory I and II, Ecology, Geology, etc. (2013) and the other in the second semester of the fourth class year (2016). It was determined that with the positive contribution of the courses taken regarding environment and the time spent on education and learning, the undergraduate students included many new concepts and subjects into environment concepts of their affective and cognitive status, and they had positive changes in their conceptual perception. However, it was concluded that this development was not at the expected level. It was even lower in certain themes and complex relationships were not fully understood.