Cladograms and phylograms

Phylogenies can indicate evolutionary relationships only, or they can convey information regarding the amount of character change that has occurred along each branch. (A) A cladogram, such as this phylogeny of the primates, has the branch tips aligned and indicates only the evolutionary relationships among the species shown. (B) A phylogram indicates evolutionary relationships and also represents the amount of sequence change along each branch by means of differing branch lengths. Here we see a phylogram of primate lentiviruses, including human immunodeficiency viruses HIV-1 and HIV-2, and various forms of simian immunodeficiency virus (SIV). Adapted from Beer et al. (1999).