Figure 34.42 A phylogenetic tree of primates. The fossil record indicates that anthropoids began diverging from other primates about 55 million years ago. New world monkeys, old world monkeys, and apes (the clade that includes gibbons, orangutans, gorillas, chimpanzees, and humans) have been evolving as separate lineages for more than 25 million years. The lineages leading to humans branched off from other apes sometime between 6 and 7 million years ago.