Rapid Evolution of Human Skulls and Faces

A recent study conducted by University College London has revealed the rapid and unexpected evolution of human brains and flat faces compared to other apes. The findings suggest that these traits provided evolutionary benefits that helped accelerate change.

Diversity in Skull Evolution

The study, published in the Proceedings of the Royal Society B, explored how skull diversity evolved among humans and related apes over millions of years. The team discovered that the human skull changed more rapidly than any other closely related species.

Dr. Aida Gomez-Robles, the study’s lead author, explained that humans are the fastest-evolving among all ape species. This reflects the importance of cranial adaptations associated with having a large brain and small faces in humans, which evolved at a rapid rate. These adaptations may be linked to the cognitive advantages of having a large brain, but social factors may also influence evolution.

Uncovering Evolutionary Differences Among Apes

To investigate, researchers created detailed 3D digital models of skulls from a group of modern primates. These models included seven species of hominids or “great apes” such as humans, gorillas, and chimpanzees, and nine species of hylobatids or “lesser apes” like gibbons.

Hominids and hylobatids diverged from a common ancestor about 20 million years ago. Since that split, hominids have developed much greater anatomical diversity, while hylobatids have remained remarkably similar. As a result, gibbon skulls appear strikingly similar across species, while great ape skulls, especially humans, show much greater diversity.

Rapid Changes in Humans

When comparing the groups, researchers found that the human skull changed at double the normal rate of evolutionary change, indicating additional forces accelerating human evolution.

However, they cautioned against attributing this speed solely to intelligence. While a larger and more complex brain may have played a significant role, social pressures might have also contributed.

Dr. Gomez-Robles added, “After humans, gorillas have the second-fastest rate of skull evolution, but their brains are relatively small compared to other great apes. In their case, changes were likely driven by social selection, as larger cranial crests on their skulls are associated with higher social status. It is possible that some unique social selection occurred in humans as well.”

Conclusion

This study provides deep insights into how human skulls evolved more rapidly compared to other apes. Distinctive features like a large brain and flat face may have offered evolutionary advantages that accelerated this change. While intelligence plays a role, social factors may have been part of this process. Research continues to unravel the mysteries of human evolution and the factors that have shaped our current form.