Human evolution is a long and winding story, stretching back millions of years, but one aspect of our anatomy evolved more quickly compared to other mammals: our large brains and flat faces. As these distinctive features spread to humans, the development of skull structure in other apes lagged behind.
Comparing the shapes of human and various ape skulls, a new study published in the journal Proceedings of the Royal Society B found that we have evolved faster than our ape relatives. While apes maintained smaller brains over the years, humans evolved much larger brains at a relatively rapid pace, an asset that may have emerged as our ancestors began to live within more complex social structures.
Ancient people acquired mental abilities
Today, humans have brains three times larger than those of our ape relatives and extinct ancestors. The primate brain began to gradually increase in size about 2 million years ago with the advent of homo kind, but about 300,000 years ago, early modern humans arrived on the scene with brains that were soon to take a completely new step in development.
Previous research has shown that as the human family tree branched, new species evolved. bigger brain this eclipsed earlier species. The brain size of early modern humans was already significantly larger than that of their predecessors, but the shape of the brain needed further refinement before it could reach its size. modern form between 100,000 and 35,000 years ago.
Read more: Culture can drive human evolution and turn us into superorganisms
Formation of the modern human skull
A new study has assessed how human evolution is related to the evolution of other apes through changes in skull structure. The researchers achieved this by looking at virtual 3D models of skulls belonging to seven hominids (“great apes” such as humans, gorillas and chimpanzees) and nine species of hylobatids (“lesser apes” such as gibbons).
Hominids and hylobatids diverged about 20 million years ago, with both groups following different evolutionary trajectories; Although hominin diversity has increased, the same has not been true for hylobatids, which is why many species in this group look the same.
However, within the hominid group, humans continued to evolve the fastest. The researchers came to this conclusion after dividing the skull models of all species into four parts: the upper part of the face, the lower part of the face, the front of the head and the back of the head. By comparing these fragments from each species, the researchers said they found that the human skulls had changed about twice as much as would be expected without some additional factor contributing to the additional changes.
“Of all the ape species, humans evolved the fastest. It probably speaks to how important the cranial adaptations of having large brains and small faces were for humans that they evolved at such a high rate,” lead author Aida Gomez-Robles, an anthropologist at University College London, said in her book. statement. “These adaptations may be due to the cognitive advantages of a large brain, but social factors may also influence our evolution.”
Social roots of evolution
Evolution eventually gave humans flatter faces and larger brains compared to other apes. This structural difference may be partly due to social changes in ancient humans.
After humans, gorillas are in second place in the rate of evolution. Although their brains are still small compared to those of other great apes, the researchers say changes in their skull shape were caused by social selection; gorillas with larger cranial crests on top of their skulls had higher social status. Researchers speculate that something similar could have given humans the skull shape we have today.
The rapid evolution of our brain can also be seen at the DNA level using human accelerated regions (HAR), parts of our genome that have evolved rapidly since we split from chimpanzees, helping us form the complex networks of neurons responsible for our unparalleled cognitive abilities.
Read more: Ancient people may have used fire to smoke meat a million years ago
Article Sources
Our authors in discovermagazine.com use peer-reviewed research and high-quality sources for our articles, and our editors review scientific accuracy and editorial standards. Review the sources used below for this article:
