Individuals’ perceptions of knowledge can have an important role in shaping their cognitions and influencing behavior. However, there has been a scarcity of studies in biology on how perceived knowledge relates to actual knowledge. This study aimed to investigate the student teachers’ perceived knowledge of biological content in relation to actual animal and species name knowledge linked to the ecosystem where they live. K-means cluster analysis and ANOVA were used. Among participants high- and low-level perceived knowledge cluster groups were observed. Results indicated that student teachers who had a high perceived knowledge tended to have better actual animal and species name knowledge than those in the low-level group. This difference remained the same during five study years. The actual animal name knowledge in these cluster groups was similar concerning local Finnish ecosystems but differed concerning the exotic ones yearly. The year that the participants enrolled in the study program had an impact on their animal and species name knowledge. High perceived knowledge was connected to good results on species identification indicating continued involvement in respective activities. As an implication: strategies for coping with work-related demands and maintaining engagement over one’s career would be important additions to the teacher education curriculum.