Cohen: At Our Origins
Off-campus studying is valuable for reaching into our past.
Dartmouth students with Prof. Lee Berger (second from left) examining a Australopithecus sediba fossil at South Africa's Malapa excavation site.
Underneath the sweat of the Malapa excavation team and Dartmouth students laid the fossilized bones of our ancestors. Kneeling with my peers, sweeping away layer after layer, we explored the earth for clues into our past. Paleoanthropologist Lee Berger paced back and forth, looming over us as we excavated the site that he and his son Matthew had found eight years before.
When paleoanthropologists find a fossil, there is a one in 250,000 chance that it is a fossil of a hominid, or ancient human ancestor. The other 249,999 belong to other African animals — bovids, carnivores, birds, micro-fauna and so many more. These discoveries are important, but less relevant to the study of human evolution that paleoanthropologists seek.
On Dec. 1, 2016, Dartmouth anthropology students improved those odds. When digging at Malapa, the cave site found by Berger, students from Anthropology 70 “Experiencing Human Origins and Evolution,” with the help of the full-time team, found the fossilized right pelvis bone from a female Australopithecus sediba.
Australopithecus sediba is an ancient human species that lived approximately 1.977 million years ago in southern Africa. It has features that bridge the gap between our oldest human ancestors and ourselves. For example, their locomotion combines upright walking and tree climbing, and their small bodies and long arms are more representative of earlier australopithecines. Two skeletons, one male and one female, have been found at Malapa, located in the Cradle of Humankind — a UNESCO World Heritage Site northwest of Johannesburg.
The Dartmouth students working on the excavation were on an extension of Anthropology 70 which biological anthropology professors Jeremy DeSilva and Nathanial Dominy led. DeSilva, describing his motivation and experience with the class, said, “For me as an educator, it was very powerful and inspiring to watch you guys learning in the space that I do my research ... I’m always thinking, ‘Well, I wish my students were here.’”
During the fall 2016 term, we explored topics of evolution by studying the environment, anatomy, diet and culture of early human species.
“When you’re at a place ... you’re engaging [with the material] in a different way,” DeSilva told me. “When you’re on site seeing the real things, you spot things, you notice things, you ask questions that you otherwise wouldn’t have asked, so the creative juices are flowing in a much different kind of way when you’re in the presence of the fossils.”
After Thanksgiving, 15 Dartmouth students and five staff members left for South Africa and took to the field. Beginning in Johannesburg, students entered the vault at the University of the Witwatersrand to examine the largest collection of hominid fossils in Africa. From there, the group moved to the Cradle of Humankind to excavate, learn and tour preexisting cave sites where hominids have been found.
We excavated in the Cradle of Humankind for three days, split up into teams that excavated, sifted and documented. The process is extremely slow and repetitive.
“I had no idea what excavation entailed,” Jackie Saralegui ’18 said.
Jessica Kittelberger ’18 agreed: “I didn’t realize the tedious process that goes into excavation,” she said.
But the excitement was contagious. Watching DeSilva and Berger bring the process to fruition by identifying the fossil we had found made the excruciatingly slow excavation worth it.
The right female pelvis fossil from a skeleton named MH2 is necessary to understand two important features of Australopithecus sediba: how it walked and how it gave birth. These can help scientists imply whether or not the species was bipedal and the level of sociability during childbirth among this ancient human species.
“The evolution of childbirth has been difficult for us to figure out because there have been so few female pelvis fossil discovered,” DeSilva said. “The MH2 pelvis gives us this new data point for looking at what birth was like in australopithecus.”
He has been working on a reconstruction of this missing pelvis fossil for Australopithecus sediba, yet it has been challenged recently because the size and shape of the bone had only been estimated. The fossil will clarify the data to provide a complete picture of the pelvis.
After finding the fossil, our journey took us to a safari in Pilanesberg National Park. Driving with elephants, zebras and giraffes was exciting, but nothing was as memorable as sitting meters away from hungry lions munching on their freshly caught impala. Minutes later, we blew out our front tire, so our professors had to brave the savanna in order to bring their students back to safety. And almost two million years before us, Australopithecus sediba would have walked those same plains.
In Cape Town, our class met with prominent paleoanthropologist Becky Ackermann, who taught us about the importance of diversity in the field. This especially resonated with our group, which was comprised of 14 female students and one male.
After, we went to Cape Agulhas, the southernmost point of Africa, to explore the region in which the earliest Homo sapiens may have lived. We ended at Pinnacle Point, a cave system on the Indian Ocean where paleoanthropologists believe human origins may have arisen.
Our experience took us throughout South Africa, exploring and studying — we were to our elbows with the best and brightest in our field, working on the most significant anthropological puzzles. We searched, questioned, and engaged in our own research projects to better understand exactly where we come from as a species.
After finding the Australopithecus sediba fossil, Kathy Li ’17 felt amazed.
“Although our contribution was small, to me personally it was huge,” she told me. “It made it real. This sort of experience is once in a lifetime.”
The fossilized pelvis we found gives us a small window into the intertwining connectivity of humanity. Paleoanthropology has the power to bring us back down to earth and realize our insignificance as a species in the great history of earth — and life upon it.
With each fossil that we find, we can better understand our evolution as a species, highlighting the similarities among us. We are all human and are only a part of a long lineage of hominids that came before us.
Correction appended (Jan. 26, 2016):
The original version of this article included stated that Australopithecus sediba is "very human-like," when it is more accurately said that "their locomotion combines upright walking and tree climbing."
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