 As a consequence of this confidence, the model organism (“source”) can represent these other unstudied species (“targets”). This basic distinction between the model or source and the phenomena or target it is supposed to represent is ubiquitous in reasoning with model organisms (Ankeny and Leonelli 2011). Zebrafish is a model or representation of vertebrate development, the target phenomena, because we expect to learn about vertebrate development generally by studying ontogeny in zebrafish specifically. We do not invest time and resources into zebrafish as a model organism only because we are interested in zebrafish. Researchers plan to make claims about somite formation from observations in zebrafish that will apply to somite formation in other vertebrates that we will never have the time or money to investigate.