Marcus Hall, University of Zurich

Individuals in communities can all be considered either competitors or else cooperators with one another, so that in the first instance, they are either parasites or hosts, or in the second instance, they are symbionts of each other by providing mutual assistance. This talk explores how seeing a dichotomy of parasites and symbionts helps us understand our biological and cultural worlds, and how there is strong evidence to suggest not only that parasites evolve into symbionts, but that symbionts evolve into parasites. A parasite, as concept and entity, provides crucial messages for ecologists as well as humanists.