Phenotypic diversity exists at all scales of evolution: from plastic development within individuals to striking disparity in traits across the tree of life. Among vertebrates, arguably no group shows more diversity in reproductive modes and life history traits than the amphibians. Here, I explore macroevolutionary patterns in reproductive mode evolution using comparative phylogenetic methods. Specifically, how losses of metamorphosis and the amphibian larval stage are driven by extrinsic and intrinsic factors. Life history traits are seldom fixed however, and readily respond to environmental heterogeneity. The evolution of developmentally plastic traits may therefore be an undervalued source of novel phenotypes. Using transcriptomic approaches, I investigate how aspects of amphibian development are regulated through environmentally sensitive gene regulatory networks, and how changes in the degree of this sensitivity across closely related species may have resulted in evolutionary divergences in life histories. Together, I use these different approaches to integrate evolution at different scales, to understand how microevolutionary and eco-evo-devo processes can result in macroevolutionary changes