Prior research on biological concepts suggests that people underestimate within-species variability and reject metamorphosis as a possible change for unfamiliar organisms. This may be due to psychological essentialism. This study investigated whether manipulating perceptions of biological variability (both within species and between species) led to increases in endorsement of metamorphosis among undergraduate students. We manipulated perceptions of variability by priming students before a lesson and by highlighting variability in the diagrams used during the lesson. Priming led to more endorsement of metamorphosis, but only among those with high prior knowledge. Our results suggest that manipulating perceptions of variability is not only possible but might be beneficial for those who have strong prior knowledge about biology.