The phenotype determines how an organism interacts with its environment and consequently it is at the center of some fundamental questions in biology. Among tetrapods, amphibians show notable variation in phenotypic characters associated with coloration, reproductive strategies, and development. In this lecture, I will present a series of empirical studies developed by collaborators and I where we attempt to discover patterns and mechanisms of phenotypic variation in amphibians related to color production, advertisement calls, and tadpoles. We developed our research within an evolutionary context and attempted to interpret the ecological and conservation implications of our results