Variation at the species level is called interspecific variation. All these cone shells belong to different species, but they are closely related and have been assigned to the same genus, Conus. Through genetic research and close scrutiny of their physical traits and morphology, researchers can create a visual representation of their relationships to each other. This allows us to better understand which species had a common lineage and which are more distant. In this graphical representation of the relationships, the ancestral node is found in the center of the circular tree. If all species with large shells were closely related, these species would be clustered on the same branch. Instead, the tree reveals that similar shell sizes and patterns evolved several times.