When it comes to human evolution, our round brains appear to be a relatively recent development.
Or at least, that’s the conclusion a team of researchers from Germany’s Max Planck Institute for Evolutionary Anthropology. The scientists have based their findings on the study of 300,000-year-old fossils from Jebel Irhoud in Morocco – some of the earliest remains of Homo sapiens.
The shapes of these ancient skull fragments, as well as others found in South Africa and Ethiopia, indicate that early modern humans had similar facial features and teeth to present-day humans, but their elongated brain case was more similar to archaic human species.
“Our data show that, 300,000 years ago, brain size in early H. sapiens already fell within the range of present-day humans,” the researchers wrote in their study, published in the journal Paleontology. “Brain shape, however, evolved gradually within the H. sapiens lineage, reaching present-day human variation between about 100,000 and 35,000 years ago.”
The paleoanthropologists used computer technology to scan the fossils, then create models of the skulls that allowed them to better image the brain case. They found that the gradual rounding process of the human skull likely came after changes led to more modern facial features.
“The brain is arguably the most important organ for the abilities that make us human,” study co-author Dr. Simon Neubauer said in a press release. “We already knew that brain shape must have evolved within our own species, but we were surprised to discover just how recent these changes to brain organization were.”
The Max Planck team’s findings line up with new discoveries in genetic studies on evolutionary changes in Homo sapiens following the split with Neandertals, who didn’t have the round brains modern humans do.
“The gradual evolution of modern human brain shape seems to parallel the gradual emergence of behavioral modernity as seen from the archaeological record,” co-author Dr. Jean-Jacques Hublin said.
By Kyla Cathey, Earth.com staff writer