This chapter examines the traditional models that describe patterns and rates of evolutionary change. It challenges the model of gradualism as the intermediacy of transitional forms, which posits that the accumulation of small variations over geological time can explain the origin of body plans. In doing so, it addresses the issues of punctuated equilibrium, particularly challenging the terms “cladogenesis” and “anagenesis,” whose conceptual distinctions remain unclear. It also demonstrates that punctuated equilibrium closely resembles phyletic gradualism in terms of evolutionary rates. Additionally, it critiques methods that attempt to quantify evolutionary rates through the assumption of gradualism. Finally, it provides reasons to support the assertion that discontinuous rates of change—rather than continuous rates of change over geological time—more effectively explain the origin of complex characters and body plans. Overall, the H-Evo-Devo Theory supports the idea that units of evolution (subspecies, species, higher taxa, and homologues) undergo precise and discrete rates and modes: an instantaneous origin, a period of stasis, and punctuated extinction. Such an assumption is supported by the fossil record and phenomena observed in embryology.