Jeff Spear is a PhD candidate at New York University. He received a Leakey Foundation grant research grant in 2020 for his project entitled “Integration and homoplasy in the forelimb of suspensory primates.”
Q: How did you feel when you learned you had been awarded a Leakey Foundation research grant?
I was thrilled. I texted a dozen people and was giddy for two days. Huge thank you to the Leakey Foundation for funding this project and helping me produce the best dissertation possible.
Q: What’s the question you’re trying to answer in your dissertation research? What work is involved?
My Leakey Foundation project is part of a broader effort to understand how the evolutionary history of apes affect the earliest stages of hominin evolution. Previous research has suggested that patterns of trait covariation and the developmental processes that drive them can bias the trajectory of evolution. My project specifically examines traits associated with suspensory adaptations in the forelimbs, and how potential changes in trait covariation impacted the evolution of apes, particularly hominins.
My research involves traveling back and forth between Airbnbs and museum basements to collect the large samples needed for a study of this kind. Although perhaps not as glamorous as field sites, museums can offer a treasure trove of data and are an essential resource for studying evolution. So a big shout out to all of the institutions and collections managers who make it possible! I will collect data primarily using a ‘Microscribe’ – essentially a robotic arm with a stylus on the end. I can move the tip of the stylus to a landmark on a bone and press a foot pedal to record 3D coordinates for that landmark. After recording 20-30 landmarks for each bone, I can take measurements between landmarks and generate limited 3D models of the bones themselves. I will use evolutionarily-informed statistical methods to look for traits associated with suspension, and examine how these traits covary using matrices. Finally, I can use the patterns of covariation to test hypotheses about how plausible different evolutionary transitions are.
Q: Why do you think research like yours is important? Why should people care about human evolution?
In a strictly practical sense, it is impossible to understand human anatomy and physiology outside of the context of our evolution. We are an upright terrestrial biped built on top of an ape built on top of a generic mammal built on top of a fish.
For anyone who has taken anatomy, you will be struck by the sheer number of exceptions to rules, the bizarre jury-rigged solutions, and the elegant beauty. The answer to ‘why’ for all of these is our evolutionary history. We may be able to describe human anatomy and physiology, but we cannot understand or explain it outside the context of human evolution. But I think most of us are drawn to human evolution for the intellectual fascination and the desire to know where we came from and why we are the way we are.
Human evolution is such a unique phenomenon in so many ways, but it was produced by the same blind process that produced all of the varieties of life on earth. That alone gives countless reasons to find it intellectually fascinating. This is my personal favorite: No other lineage in the history of earth has ever become an upright biped, and today we are alone in that role. Yet the fossil record shows that our solitary state has not always existed. There are dozens of ways to be an upright biped, as demonstrated by the sheer number of our extinct relatives. The human lineage seems to have gone through multiple radiations in only a few million years. But upright bipedalism only appeared once. So why if there are so many ways to be an upright biped does it only evolve once? We are not unique in our uniqueness, but we are among a small, select group of vertebrates. So many other great evolutionary innovations for locomotion, from theropod-like pronograde bipedalism to powered flight to legless slithering, have evolved multiple times.
I believe the answer is the same as the answer to our anatomical exceptions and beautiful jury rigged bodies – evolution is fundamentally a historical process. We were produced by a unique interaction of historical template and novel selection pressure. My research seeks to better understand that historical template.
Q: What are you working on right now? Or what’s next?
Unfortunately, due to museums shutting down for COVID-19, I had to stop data collection just as it started. For now, I am diving deeper into the methods and techniques I will use in this project, revisiting classic papers, and working on other projects. But I’m looking forward to my next discoveries in the bowels of a museum.