This chapter introduces a new theoretical framework that supports the recognition of subspecies and species as units of evolution. It begins by exploring the challenges of recognizing subspecies and species as evolving entities in their traditional sense. For example, under this view, defining and delimiting subspecies is a challenging endeavor, while species are associated with numerous concepts, making it difficult to reconcile them with a general notion of “species.” Nevertheless, the H-Evo-Devo Theory offers a framework that grants subspecies and species a distinct ontological reality. According to this model, subspecies are natural groups that collectively share a common body plan but are separated from each other by small morphological gaps in simple characters as well as by the fact that they live in different environments. Subspecies do not represent the early stages of the origin of species; rather, they are groups that diversify to adapt the species to different environments, thus protecting species from extinction. Meanwhile, species are discrete entities that exhibit the first step in morphological gaps in complex characters. More importantly, they are distinguished from other taxa by being the least inclusive body plan within a hierarchy of body plans. This perspective aims to provide the long-awaited general notion of species, offering a definitive resolution to the species problem that has perplexed evolutionary biologists for years.