Beyond the Bones: Why Homo naledi belongs in every science classroom

In my last blog post, I left you hanging with two scientific issues regarding Homo naledi—first was its age and second was seeing if all those fossils actually got into the Dinaledi chamber by way of the same 8-inch “chute” that the underground astronauts used to access the chamber.

Upon the announcement of the Homo naledi discovery in 2015, one frustration for many people was the lack of a date associated with the bones. Based on the anatomy of the bones and how primitive some of them are, many people suspected that Homo naledi might date back to the dawn of the genus Homo in the 2 million-years-ago period.

After much work attempting to date the fossils and the cave sediments, in May of 2017 the team was finally able to announce definitive dates for the Dinaledi chamber specimens. Using multiple methods of dating (including Electron Spin Resonance and Uranium-Thorium methods) processed independently by multiple labs, the bones were found to be between 236,000 and 335,000 years old.

This very young date surprised many people and suggests that Homo naledi was alive in southern Africa until the advent of our species, Homo sapiens, in the area. The potential presence of this small-brained relative alongside modern people has paleontologist Lee Berger and his team questioning if Homo naledi might have been responsible for some of the stone tool artifacts found in South Africa at that time.  This will certainly be the focus of future study in the archaeology of South Africa!

Naledi face

Homo naledi
Photo by Mark Thiessen, National Geographic

Many people were highly skeptical of the “ritualized body disposal” hypothesis since it simply seemed so implausible.

Given the fact that all other reasonable causes for the presence of the bodies had been ruled out, the team still needed to work to disprove their own idea. If the only access to the Dinaledi chamber was the chute, it made sense that there should be remains of Homo naledi at the landing zone immediately below the chute. The 2013 fossils were excavated more than 10 meters away from the chute.

In an attempt to gain evidence that might support or refute the chute-entry hypothesis, Berger reassembled most of the excavation team just last month (September 2017) and began a three-week expedition to seek these answers, as well as to further excavate the Lesedi chamber in hopes of recovering more of the Neo skeleton.

The team met with success as they discovered Homo naledi bones in a debris “cone” (pile) under the chute. There appears to be at least one skeleton in a mash of bones and sediments that will require further excavation. This discovery does offer strong support to the hypothesis that Homo naledi did indeed enter the Dinaledi chamber via the chute.

Becca over the Mash

Becca Peixotto excavating Homo naledi fossils near the “chute”. Photo courtesy Elen Feuerriegel

To add new (and currently unresolved) intrigue to the story, new fossils were spotted in very narrow passages off the Dinaledi chamber—a discovery which will require further investigation. This last point gets to the main point of this post: I think as many students as possible should be studying the story of Homo naledi and here’s why.

As many students as possible should be studying the story of Homo naledi and here’s why.

The first and perhaps most obvious reason involves the great science this discovery has unleashed. As a self-confessed paleo geek, I think everyone should be well aware of the biggest human origins story since Lucy came on the scene in the mid 1970s. But the value of this story to young students goes well beyond the “bones and stones” of archaeology and paleontology.

First, as a teacher of middle school students, I love that this project has been active since 2013. I have former 6th-grade students who are now following the latest news as high school juniors. This is a great example that scientific discoveries are not just that magic EUREKA moment in a lab, but rather an ongoing series of hypotheses and investigations. It also shows students that answers do not come easily like the answers to questions at the end of a text book chapter or in a Google search.

In a world that values instant gratification, such a continuing investigation is a powerful model of how science really works.

Berger and boys

Dr. Lee Berger with my students in 2012 & again last month. They wanted to recreate their photo from 6th grade. Photo courtesy St. Mark’s School of Texas

When you take the time to learn about the Homo naledi discovery, another thing that is important is the open access that Dr. Berger has made a hallmark of this project.

Unlike most discoveries in the field of paleoanthropology, each stage of the Homo naledi story has been deliberately open access. From live-tweeting all of the excavations since 2013 to wiring the Rising Star cave with Wi-Fi so that students from all over the world could participate in hangouts with the team via the National Geographic Explorer Classroom program through Facebook live broadcasts.

In addition to inviting students to visit the fossil chambers virtually, Berger’s team has scanned many of the Homo naledi fossils and made them available to 3D print for free from Morphosource.com. In my classroom, I had 3D prints of the original fossils within days of the official announcement. When holding precise 3D prints of fossils that are in the news, students get especially excited and ask amazing questions.

naledi-3d-comparison

Comparison of a real Homo naledi fossil and my 3D print of it. Photo courtesy John S. Mead

As someone who has followed this investigation since day one, I have gotten to walk my students through a great example of the scientific method in action. Rather than be a simplistic straight line from hypothesis to experiment to conclusion, the story of the Homo naledi discovery shows how science works in the modern world by combining observations, exploration, hypothesizing, and teambuilding.

Perhaps the most powerful of these characteristics is the impressive team nature of this project. Traditionally, human origins are studied by research groups of only a few senior scientists who have guarded data closely.

caving team

The Rising Star Expedition caving support team was made up by the Speleological Exploration Club, a founding member of the South African Speleological Association founded in 1954. They  played an important role in keeping the Homo naledi excavators safe.  Photo Courtesy Dave Ingold

As I’ve pointed out, the Homo naledi team was more than a handful of folks. The most visible members of the team were Drs. Lee Berger & John Hawks along with the six Underground Astronauts and the two cavers who initially discovered the bones. However, what many people do not know is that the “team” consists of more than 150 scientists in the fields of paleoanthropology, osteology, geology, ecology, paleontology, geophysics, and exploration. Indeed, when you look at this team in comparison to other scientific endeavors, it is one of the largest science teams in any field and compares in size to the large teams that run NASA missions or make work at the CERN supercollider possible.

41-Elen-Feuerriegel-working-with-cranial-corner-in-background-john-hawks-cc-by

Elen Feuerriegel and other Rising Star Workshop members analyze data sets about Homo naledi. Photo courtesy John Hawks

Another important “teamwork” lesson for students is that the understanding that this discovery was made possible by a whole host of “non-scientists.” For many students who do not see themselves as “good at science,” this is an important point.

Homo naledi would not have become such a huge discovery if it was not for the following groups. The volunteer cavers who were responsible for the safety of the excavators, photographers and videographers who documented the fossils and the work of the scientists, paleo-artists like John Gurche who created the iconic “grumpy” face of Homo naledi, tech gurus who helped scan the fossils and arranged for Wi-Fi in the cave, so students would have real-time access to this discovery, camp management staff who kept the expeditions fed and running smoothly so that the science of this project could occur without interruption. You can also add teachers and science journalists who helped spread the news and significance of this find to people who otherwise would have missed it.

WIts-7948

Members of the Hill Exploration team that seeks new fossil deposits in the caves of South Africa. Photo courtesy of John S. Mead

If what I’ve mentioned so far is not enough to convince you that the Homo naledi story should not be widely taught, I also see it as a great example of what is a dying endeavor in the 21st-century: EXPLORATION!

This scientific discovery has elements of exploration and adventure, which students often miss when they encounter science in their classes today. In our increasingly urbanized world, many people believe that “everything has been explored already.” This project illustrates that even in the most heavily explored area on Earth for human fossils, there can still be a huge discovery. This lesson should be extrapolated for all of us to be thinking about what we might discover in our own neighborhoods that we think we know so well. If we take this lesson to heart it can help us fight the narrow vision that comes with “Backyard Syndrome”—the tendency to overlook great things that exist right under our noses!

Indeed, it was this realization that prompted me to create my current twitter handle (@Evo_Explorer) in hopes that I can help guide people to explore the wonders of evolution and biology that may be in our own intellectual backyards. Please feel free to join me on this ongoing journey!

JM with Skulls

Join me and some of my “friends” exploring the mysteries and wonder of evolution!  Photo courtesy Amanda Glaze

If you’re interested in sharing the Homo naledi with your friends and family, I created this video overview last month for people new to the story to get “caught up.”

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