The aim of this research is to investigate student science teachers' opinions about the causes of degradation of ecosystems and the effects of such degradations on the environment. This research focuses on the following questions: What kind of descriptions do student science teachers ascribe to the reasons of degradation in ecosystems? What are the effects of ecosystem degradations on the environment? What are the misconceptions in relation to degradations in ecosystems? A total of 130 participating students, who were studying to become science teachers at Faculty of Education of Necmettin Erbakan University in Turkey, participated in this study. To reveal the participating students' opinions about the reasons for degradations in ecosystems and their effects on the environment, they were asked to answer two open questions: (1) What are the reasons for degradations in ecosystems? (2) What are the effects of degradations in ecosystems on the environment? The participants were asked to answer these two questions. Data obtained from the questions were analyzed and the frequencies of the answers were classified in different categories. Moreover, these included some misconceptions such as "the greenhouse effect can lead to skin cancer" and "ozone layer depletion leads to global warming". The findings are compared with related literature and suggestions are presented.