Evolutionary tree showing areas and habitats

Allan Krill

Speciation requires reproductive isolation, for which there can be many causes. Sometimes this is by physical separation, but there are many other possibilities. Gorillas and chimpanzees had an arboreal ancestor in the forests of central western Africa. But gorillas chose a different diet than chimpanzee, so they diverged within the same area. Here is an explanation, from p. 13 of the book: Chimpanzees and human evolution

The fundamental difference between chimpanzee and gorilla diets is that gorillas, because of their large bodies and guts, can subsist on much lower quality food. Both apes prefer to eat fruit when it is available. However, comparisons in the same forests show that, as fruit becomes rarer, gorillas fall back on increasing amounts of pith, leaves, and woody stems, while chimpanzees continue to search for higher-quality food (reviewed in Wrangham 2006; Harcourt and Stewart 2007a).

Here is another evolutionary tree, where I mention the areas and foods of speciation.

Join anthropogeny@groups.io to automatically receive all group messages.