Abstract One potential source of folkbiological knowledge loss is changing patterns of interaction with the natural world stemming from “modernizing” material change. This article compares models of plant knowledge among age-matched groups of children and adults in two communities of a municipality located in the highlands of Chiapas, Mexico. Use of the Cultural Consensus Model (CCM), analysis of residual agreement, and examination of model content show that while plant knowledge remains fairly robust in the municipality, devolutionary change is ongoing and manifests in the urbanized municipal town center relative to a rural outlying hamlet. Quantifying disparities in folkbiological knowledge is considered as a preliminary step in understanding general processes of culture change. Recent investigations into domain-specific folkbiological expertise in adults and the acquisition of folkbiological models in children shows that differences in propositional knowledge interact with culture-specific reasoning strategies and have profound consequences for value complexes and environmental behavior.