Herschel Walker isn't the only one wrong about humans and apes

By Joe Felsenstein

About a week ago there was a media flap when the leading Republican running for senator from Georgia, football great Herschel Walker, asked why there were still apes, if humans have evolved from apes. This is a common silly creationist talking point. It is usually stated as the question “why are there still monkeys”. There's really not much reason to spend time refuting it; it reflects an elementary misunderstanding of what evolutionary biologists say about human evolution.

But what was more astonishing was how our knowledgeable and sophisticated press explained the matter to its readers. Here are some jaw-dropping explanations:

  • CNN’s Editor-at-large Chris Cilizza explained here that “Humans and apes evolved from the same genetic ape ancestors, a species now long extinct. (It’s known as “common descent.”) We did not, however, evolve directly from the current occupants of your local zoo. They are one branch of descent from their ape ancestors. Humans are another.” And he quotes an evolutionary biologist, Fabio Mendes, as saying that “Humans and apes evolved from the same genetic ape ancestors, a species now long extinct. (It’s known as “common descent.”) We did not, however, evolve directly from the current occupants of your local zoo. They are one branch of descent from their ape ancestors. Humans are another.”
  • The digital media report The Hill played it safe, relying on PBS: “According to a PBS FAQ about evolution, “Humans are more closely related to modern apes … but we didn’t evolve from apes, either. Humans share a common ancestor with modern African apes. … Scientists believe this common ancestor existed 5 to 8 million years ago. Shortly thereafter, the species diverged into two separate lineages. One of these lineages ultimately evolved into gorillas and chimps, and the other evolved into early human ancestors called hominids.” (The PBS FAQ was actually from a 2001 science program “Evolution”, a series funded by a foundation of Paul Allen’s. It can be found here). It in turn has links to some respectable sources, some to the Talk.Origins site, which itself cites a couple of articles here at Panda’s Thumb.
  • A fact-checking site, Politifact, has its article here. It is slightly more vague on the issue, but does say that “Humans and the apes known today both evolved from ancient apes, who are now extinct. This split occurred between 6-8 million years ago based on genetic and fossil evidence. Over time, humans and apes have been evolving in their own ways to adapt in their respective environments.” and also that “Humans and modern-day apes both evolved from ancient apes, who are now extinct. Anthropologists using genetic and fossil evidence pinpoint it between 6-8 million years ago. Humans and the apes seen today evolved differently over time.”

The message is clear. Apes, who, us? We evolved from something, but it wasn’t an ape. Nosiree! Apes evolved separately from us, right?

Not right, of course. Which means we ought to discuss why so many people who know evolution happened can’t seem to say that we evolved from apes, that in fact we are apes.

Let’s think about this …

A quick summary of the situation might be to note that

  1. About 60 years ago it was still thought that the most recent common ancestor of humans and apes lived 25 million years ago. That would place most apes in a sister-group to humans. It was thus possible to say that the common ancestor wasn’t an ape. This was much less upsetting to the public than saying that any of their ancestors had been apes.
  2. The “evolutionary systematics” position on classification, which was dominant then, did not require groups in the classification system to be monophyletic (to have their very own common ancestor). Apes could be placed in one group, humans in another, even though some of the descendants of the common ancestor of all apes included humans.
  3. By this point, biologists should have started admitting that humans were descended from apes. They sort-of did, though usually reassuring the public that they weren’t descended from any hairy and gross animal like present-day apes such as chimpanzees and gorillas. This evades the question of whether any of our ancestors were hairy and gross.
  4. But by the 1970s it was becoming clear that humans were in a clade that included chimps and gorillas. And that our lineage connected with apes less than 10 million years ago. And monophyletic classification (“phylogenetic systematics”) was becoming the dominant approach. In the 1980s it became clear that the lineage with the two species of chimpanzees was the sister lineage of hominids. From that point on, it was inevitable that popular-science discussions of human ancestry would finally admit that we had ancestors that were apes. And that we ourselves were apes. Jared Diamond was straightforward about that in his book The Third Chimpanzee: The Evolution and Future of the Human Animal in 1991. But Francisco Ayala was more circumlocuitous in his 2010 book Am I a Monkey? Six Big Questions about Evolution.

It has taken an extraordinary amount of time for popular writings in biology to admit that you not only have an inner fish, but an inner monkey and an inner ape.

Have I got this picture wrong? Discuss …