The shape of species abundance distributions can be predicted by looking at both the number of individuals and their biomass. By plotting species points in log numerical abundance, log biomass space, a triangular area is formed based on body size range and abundance limits. This relationship helps predict the form of the distribution, with numerical abundance following a power curve and biomass abundance often showing a unimodal curve. This model can be used as a baseline for comparing actual communities and understanding the impact of sampling methods. It suggests that models of species abundance distributions should consider different ways of measuring abundance to better understand ecological communities.