We study mitosis and cell division using comparative and synthetic approaches in the related genetically tractable species. The commonly used model organism Schizosaccharomyces pombe and its unusual cousin Schizosaccharomyces japonicus have similar genetic makeup but differ in their approaches to mitotic division. For instance, S. pombe leaves the nuclear envelope intact throughout the cell cycle but S. japonicus breaks it during mitosis, similarly to human cells. While cells of both species divide in the middle, they use different mechanisms to position the division site. The two organisms also maintain markedly different cell sizes, with S. japonicus being much larger than S. pombe. These salient differences between the two species provide us with a unique opportunity to uncover fundamental mechanisms underlying mitosis and cytokinesis and to evaluate functional and evolutionary fluidity of these processes.