Kristian Carlson
Bringing our human ancestors back to life
Associate Professor Kristian Carlson’s first encounter with Sterkfontein was as a university student in the US in the early 1990s. Not for a moment did he suspect, however, that he would one day work there.
“I remember the wonderment I experienced upon seeing replicas and photographs of Sterkfontein fossils for the first time in a class. What did these creatures look like, and how did they behave when they were alive? What did they do all day? Having a chance to observe and measure replicas of these fossils in class brought them to life,” Carlson says.
“Later, as a graduate student pursuing a doctoral degree in Biological Anthropology, I was fortunate to travel to South Africa and see the Sterkfontein fossils in person. Little did I realise then that my career path would lead me back to the University of the Witwatersrand, where I served as a faculty member for several years in the Evolutionary Studies Institute.
“It was during this period that I started participating in collaborative research with fossils from Sterkfontein, Swartkrans and other sites around South Africa. This work has been deeply satisfying from an intellectual standpoint. It also has brought me full circle since I have had opportunities to work with Wits undergraduate students and help introduce them to these amazing fossils for the first time – just as I had experienced decades earlier.”
Carlson’s area of interest is primate functional morphology, including hominins. His job is to examine fossils, sometimes employing X-ray and digital technologies, and figure out how ancient species interacted with their environment.
“My efforts focus on comparative and functional evaluations of individual fossils, as well as the rare examples of associated fossilised skeletal remains. This work is aimed at understanding how human ancestors were adapted to the ecosystems in which they engaged,” he says.
More than anything, Carlson wants to understand why some species succeeded and others did not: “What behaviours or capabilities allowed some human ancestors to be successful in an evolutionary sense? What caused other human relatives to not be evolutionarily successful and go extinct?
“Reanimating our ancestors is akin to solving mysteries. It requires the power of deduction. More than anything, I enjoy asking tough questions about human evolution and carefully sorting through potential answers for the most likely explanations.”
The Cradle of Humankind, encompassing Sterkfontein, Swartkrans and several other archaeological sites, is simply the best place in the world for his kind of sleuthing.
“The Cradle of Humankind has provided, and continues to provide, an unrivalled window into the early evolutionary history of humanity. The sheer number of human ancestor fossils, the wondrous examples of partial skeletons that have been recovered from different sites, and the time depth represented in the Cradle collectively document a unique record of human presence and activity.
“Morphological variation that is recorded in the fossils from the Cradle both across time and through time offers a rich account of diversity in the human evolutionary record. Deciphering the human story, while complicated by this vast and varied fossil record, is also feasible because of the wealth of fossil material preserved in the Cradle,” Carlson says.
He points out that Sterkfontein itself is a rare site not only because of the number of fossils it gives up but also by its sheer longevity. Even predating the modern synthesis – the amalgamation of Charles Darwin’s theory of evolution and biologist Gregor Mendel’s theories on heredity, which emerged in the early 20th century – the Sterkfontein excavations provide proof about our origins.
“Upon the discovery of hominin fossils at Sterkfontein in the early 20th century, the site had a vital historical role in corroborating the scientific significance of the Taung Child fossil, i.e. documenting the full extent of evolution in the human lineage. It is fascinating to me that since these early days, even prior to the modern synthesis, Sterkfontein continues to play a special role in supporting the intellectual development of biological evolutionary thought, particularly with respect to humans.
“And it is incredible that Sterkfontein has done so for nearly 100 years,” Carlson says.