Figure 3. Evolutionary dendrogram of apehominid evolution.

The vertical axis represents time and ends in the present with gibbons, orangutans, gorillas, chimpanzees, and humans contemporaneously existing. The vertical distance from the top to a branch point along the dendrogram is the time to coalescence. Where ape lineages join represents when the two species shared a common ancestor. All modern apes live in closed tropical forests, and obtain all of their nutrition there. Their last common ancestor to the apes would presumably have lived in a similar environment. During early hominid evolution, human ancestors left the forest for the savannah and other ecosystems and their dietary repertoire greatly expanded. Eventually their diet is hypothesized to have included more meats, fermented foods, and, most recently, large amounts of starch due to the advent of agriculture.