Concept: The species-area relationship describes how species richness increases with increasing area.Explanation:
Alexander Von Humboldt, during his explorations of South America, observed that within a region, species richness increased with increasing explored area — but only up to a certain limit.
He documented this relationship, which is now expressed as: logS=logC+ZlogA where S = species richness, A = area, Z = slope, C = y-intercept.
This observation by Humboldt laid the foundation for the species-area relationship in biogeography.