 On the phylogenetic tree in  Figure 1,  time passes from left to right with extant groups labeled on the terminals of branches on the  right.[1]  Starting from the left there are two distinct branches, one leading to Cartilaginous fish (sharks and rays), and the other to a node. From that node the branches split, with one leading to Ray-finned fishes, and the other leading to another, more recent node (that ultimately leads to frogs, lizards, and mammals, among other taxa). Branches may be read as representing ancestral lineages, with nodes representing common ancestors that diverged (or split) into distinct lineal branches.