The concept of what it means to be human has evolved over time. Initially, Homo sapiens were seen as the pinnacle of humanity, with our complex thoughts and deep emotions setting us apart. Other early human species like Neanderthals were considered steps in our evolutionary journey, eventually fading away because we were deemed superior.
However, recent advances in ancient DNA technology have reshaped this narrative. Researchers can now extract DNA from ancient hominins, shedding new light on our early ancestors and human relatives. These discoveries challenge the notion of human exceptionalism. Throughout most of human history, we coexisted with various other early human groups that, in many ways, were quite similar to us.
“We can perceive them as fully human, albeit with intriguing differences—a distinct way of being human,” says Chris Stringer, an expert in human evolution at London’s Natural History Museum. This revelation highlights that there isn’t a single mold for humanity.
Furthermore, our ancestors had close and sometimes even intimate interactions with these other groups, such as Neanderthals, Denisovans, and enigmatic “ghost populations” only known through DNA evidence.
In essence, we find ourselves in a unique period in human history where we are the last remaining branch of a diverse family tree.
A WORLD WITH MANY HOMININS
Modern science has illuminated a fascinating chapter in our history. About 300,000 years ago, Homo sapiens made their debut in Africa, coexisting with a diverse ensemble of other hominins, as Rick Potts, the director of the Smithsonian’s Human Origins Program, explains.
In Europe, Neanderthals were going about their business, while Homo heidelbergensis and Homo naledi were flourishing in Africa. The diminutive Homo floresiensis, often referred to as the “Hobbit,” inhabited Indonesia, and the long-legged Homo erectus roamed the landscapes of Asia.
It became apparent that these hominins weren’t our direct ancestors but rather akin to our distant cousins. They diverged from a common ancestral lineage and charted their unique evolutionary paths.
Remarkable archaeological discoveries unveiled their complex behaviors: Neanderthals adorned cave walls with paintings, Homo heidelbergensis hunted large and formidable creatures like rhinos and hippos, and some experts suggest that even the small-brained Homo naledi practiced burial rituals in the cave systems of South Africa. Recent research has even revealed that early humans were constructing wooden structures before Homo sapiens emerged.
A burning question arose among researchers: Did our ancestors engage in interbreeding with these other human varieties?
For some, this idea was difficult to fathom. Many initially believed that as Homo sapiens ventured beyond Africa, they simply replaced these other groups without any form of intermingling. Archaeologist John Shea of Stony Brook University in New York once envisioned Neanderthals and Homo sapiens as rivals, with a belief that if they crossed paths, it would likely result in conflict.
DNA REVEALS ANCIENT SECRETS
The unlocking of ancient DNA’s secrets has unveiled profound interactions that have shaped our current identity.
In 2010, Swedish geneticist Svante Pääbo and his team undertook a formidable challenge. They managed to piece together fragments of ancient DNA, constructing a complete Neanderthal genome—a remarkable achievement that was once considered impossible and earned Pääbo a Nobel Prize in the recent past.
This capability to decipher ancient DNA has triggered a revolution in the field, and its precision continues to advance.
A compelling example of this advancement lies in a Siberian cave, where researchers applied these techniques to a pinky bone and substantial molars. Within, they discovered genes that defied previous categorization, as highlighted by Bence Viola, an anthropologist at the University of Toronto involved in this groundbreaking research. These genes belonged to a previously unknown hominin species, now known as Denisovans, uniquely identified through their DNA alone.
With the Neanderthal and Denisovan genomes at their disposal, scientists embarked on a quest to compare them with modern humans. This led them to identify distinct segments of DNA where interbreeding had evidently occurred, leaving behind clear evidence of cross-species exchanges.
THE NEW HUMAN STORY
DNA evidence has unveiled a compelling narrative of Homo sapiens engaging in interbreeding with various groups, including Neanderthals and Denisovans. This genetic detective work has also uncovered hints of enigmatic “ghost populations”—groups that have left their mark in our genetic code, even though their fossils remain elusive.
Pinpointing the exact time and place of these interactions proves challenging. Our ancestors appear to have mingled with Neanderthals shortly after their exodus from Africa into Europe. Encounters with Denisovans likely occurred in regions of East and Southeast Asia.
As Rick Potts from the Smithsonian notes, our ancestors didn’t possess maps or knowledge of their destinations. Instead, they ventured into new territories, where they encountered populations of people who may have looked somewhat different but were nonetheless open to mating and gene exchange.
While Neanderthals exhibited distinctive features, such as larger noses and shorter limbs compared to Homo sapiens, these distinctions weren’t insurmountable barriers. According to archaeologist John Shea, our ancestors likely thought, “Well, these folks appear a bit different – perhaps in terms of skin color or facial features – but they’re interesting; let’s engage and communicate with them.”
The notion that modern humans, particularly those of European descent, represented the pinnacle of evolution has its roots in a bygone era characterized by colonialism and elitism, as Janet Young, the curator of physical anthropology at the Canadian Museum of History, points out.
It’s intriguing to note that a Neanderthal painting, shaped to align with the beliefs of a eugenics advocate, found its way into textbooks and museum exhibits, perpetuating this outdated idea.
The recent discoveries have completely overturned the once-prevailing notion that earlier, more primitive beings gradually evolved into the sophisticated Homo sapiens we know today. Alongside genetic evidence, archaeological findings have illuminated the complex behaviors of Neanderthals, including their hunting techniques, culinary practices, tool usage, and even artistic expression.
However, despite this growing body of knowledge demonstrating the similarities between our ancient human cousins and us, the stereotype of ape-like cave dwellers persists.
Artist John Gurche is on a mission to change that perception. His specialty involves crafting lifelike models of ancient humans for renowned museums like the Smithsonian and the American Museum of Natural History, with the aim of bridging public understanding with scientific advancements.
Inside his studio, skulls and sculptures populate the shelves as he meticulously sculpts a Neanderthal head, embedding individual hair strands into silicone skin.
Gurche acknowledges the persistent image of the caveman but emphasizes the importance of accuracy in his work. Beyond anatomical precision, he seeks to infuse emotion into his portrayals, reminding us that these were once real individuals who experienced the full spectrum of human emotions, from joy and grief to pain.
“They’re not creatures from a fantasy realm; they were living, breathing beings,” Gurche emphasizes.
MANY CONNECTIONS STILL TO BE FOUND
Not all fossils yield valuable genetic insights, especially those that are exceptionally old or have endured unfavorable environmental conditions. Gathering ancient DNA from Africa, the birthplace of Homo sapiens, has been challenging due to heat and moisture causing DNA degradation.
Nevertheless, there’s optimism that as DNA technology advances, we will penetrate further into the past and extract ancient genomes from various corners of the globe. This ongoing progress promises to add more intricate details to our ever-evolving understanding of human history.
Despite being the sole surviving human group, the now-extinct branches played pivotal roles in our history and continue to influence our present. They are threads in the tapestry of our shared humanity, connecting every individual, as emphasized by Mary Prendergast, an archaeologist from Rice University.
When we examine the fossil record, delve into archaeological findings, and explore the genetic narrative, a common bond emerges, revealing that our similarities far outweigh our differences.