 Developmental biology is the science that investigates how a variety of interacting processes generate an organism’s heterogeneous shapes, size, and structural features that arise on the trajectory from embryo to adult, or more generally throughout a life cycle (Love 2008; Minelli 2011a). It represents an exemplary area of contemporary experimental biology that focuses on phenomena that have puzzled natural philosophers and scientists for more than two millennia. How do the dynamic relations among seemingly homogeneous components in the early stages of an embryo produce a unified whole organism containing heterogeneous parts in the appropriate arrangement and with correct interconnections? More succinctly, how do we explain ontogeny (or, more archaically, generation)? In Generation of Animals, Aristotle provided the first systematic investigation of developmental phenomena and recognized key issues about the emergence of and relationships between hierarchically organized parts (e.g., bone and anatomical features containing bone), as well as the explanatory difficulty of determining how a morphological form is achieved reliably in offspring (e.g., the typical shape and structure of appendages in a particular species). Generation remained a poignant question throughout the early modern period and was explored by many key figures writing at the time, including William Harvey, René Descartes, Robert Boyle, Pierre Gassendi, Nicolas Malebranche, Gottfried Wilhelm Leibniz, Anne Conway, Immanuel Kant, and others (Smith 2006). Observations of life cycle transitions, such as metamorphosis, fed into these endeavors and led to striking conclusions, such as Leibniz’s denial of generation sensu stricto.