Mechanistic Origins and Properties of Emergent Simplicity

Natural microbial communities exhibit immense levels of diversity as well as significant functional redundancy. This complexity has been a major roadblock to understanding these ecosystems and their responses to perturbation. Nevertheless, several recent theoretical and empirical studies indicate that the predictive power of simple coarsened models may improve with community richness ("emergent predictability"). Importantly, common modeling frameworks like Lotka-Volterra and consumer resource models do not generally display this behavior. This makes understanding the origins and properties of this phenomenon an important question. This talk will investigate a simple extension of a consumer-resource model that does exhibit emergent predictability, and demonstrate two mechanisms for it to arise: one that comes from "anisotropic self-averaging", and the other from an environmentally mediated feedback loop.