Phylogenetics, the study of evolutionary relationships in organisms, is part of the larger field of systematics, including taxonomy. The term taxonomy connotes the process and methodology for the naming and classifying of organisms. The context of evolutionary biology is phylogeny, the connections between all groups of organisms as understood by ancestor/descendant relationships. The molecular mechanisms of organisms studied strongly suggest that all organisms on Earth have a common ancestor. Thus, the species are related by having evolved from the same common (now extinct) ancestor. Such a relationship of species is called phylogeny, and its graphical representation is called a phylogenetic tree.