A century and a half ago, Charles Darwin presciently wrote in his classic work, The Descent of Man: “It is somewhat more probable that our early progenitors lived on the African continent than elsewhere.” To understand much more of what we are now learning about Darwin’s really good guess, J. BROOKS SPECTOR visited Professor Lee Berger at the University of the Witwatersrand.
For as long as I can remember, palaeontologists and palaeoanthropologists were my favourite scientist-adventurer heroes. They were people like Roy Chapman Andrews (one actual model for the fictional Indiana Jones) who rode off into Mongolia’s Flaming Cliffs in the midst of Chinese civil war and found the first known dinosaur eggs while he and his helpers fought off Mongolian bandits. Or, like the Leakey family, they uncovered ancient Homo habilis skull fragments among the barren contours of the Olduvai Gorge of East Africa’s Great Rift Valley. Or they waged a fierce, increasingly aggressive competition on behalf of their respective museums – like geologists Edward Cope and Othniel Marsh did in the 19th century – to discover an incredible variety of new but ancient species in America’s frontier territories.
While palaeoanthropology ultimately would not become a viable career choice for me (in the end, calculus was an impenetrable wall), for decades, as each new ancient primate discovery was announced anywhere in the world, they always thrilled me – especially the African ones. Eventually, I was lucky enough to visit several of the caves at the Cradle of Humankind under the tutelage of some of the scientists working there. This way one could actually see places in all those underground caverns where the fossil remains were being uncovered – in areas off-limits to routine visitors. A visit like that gives an extraordinary sense of history – stretching back millions of years.
And so, in the wake of two separate yet astonishing announcements, I went to speak to professor Lee Berger – one of the scientists in the centre of both of these discoveries, as well as numerous others over the past several years.
Berger is at his office on the Wits University campus and we meet early in the morning, a few days after he has returned from his most recent trip – this time to China. This man travels a lot. Increasingly, Discovery and National Geographic Channel TV viewers are seeing him pop up all over the world, poking around old fossil sites as well as new ones. Always there is this extraordinary light of enthusiasm playing across his face. He is a man possessed – not by demons – but by an unqualified love for his work.
The walls of Berger’s office are covered with certificates and plaques – the artefacts of a life in science – and a life leading up to it. There are mementos from student days – 4-H Club state president from high school days in the US – and on to the newest prized addition, South African citizenship. On the desk are fossils, models of fossils and books about fossils. It is a cold winter’s morning, but, thankfully, Berger has a cheerful, noisy espresso maker in his office.
Several years back, Berger and his team had answered one of the more puzzling questions about South Africa’s treasure trove of primate prehistory. The remains of the “Taung Child” are famous: so many things about it point to it as having an important place along the evolutionary journey towards modern humans – although yet other features were more complex and confusing. Nevertheless, this specimen of Australopithecus africanus eventually transformed our understanding and appreciation of where humanity first evolved, helping to place it firmly in Africa.
Since Raymond Dart’s discovery in 1924 of the Taung Child, there has always been speculation about how it came to die – was it from natural causes like disease, from an accident – or was it killed by an unknown predator. Berger’s moment came when he carefully compared that famous skull to those of contemporary monkeys that had been killed by large predator birds. Bam! Voila! Eureka! Vadda voom!
The tiny, fossilised Taung Child skull – it is small enough that it can nestle comfortably in the palm of one’s hand – had the same three point marks of where a bird’s claw had fastened on to it to kill this primate prey and carry it away to eat or feed to its chicks. That’s the elemental part of the great “circle of life,” preserved in a famous fossil. Amazingly, this “three-point play” carried out by an eagle or another raptor is actually clearly visible – now that one knows where to look and what to look for – even on casts of the skull that had been made carefully by Dart himself. Rather than instant bolts from the blue, this meticulous, close-order observation of nature, instead of a retreat into the lab, forms one key element of what we will call the Berger approach. But like Napoleon’s wish for his generals to aid in their success, he has luck, along with talent.
More recently, Berger’s then pre-teen son, Matthew, discovered the first part of the remains of Australopithecus sediba, popularly named “Karabo” or dawn. Most recently, in a development announced in China, Berger’s wife, radiologist Jackie Smilg, looking for a PhD topic, had chosen to carry out a tomographic scan of rock from that same deposit and she and her team found still more of Karabo’s fossilised bones inside this chunk of rock. There must be something special in the water in the Berger home – his daughter, Megan, recently carried out a prize-winning science fair project that began when she asked her father how long it actually took for remains to become fossils.
Recently, too, Berger – together with a whole army of other scientists working around the world in a broad range of very specialised fields – did something so amazing it sounds at first hearing like something that is cross-fertilised between CSI New York and Jurassic Park. They carefully removed dental calculus from around Karabo’s teeth – fortunately those creatures weren’t au fait with dental floss or brushing three times a day – and through some clever and careful analysis managed to identify the actual types of plant matter on Karabo’s dentition.
Bring that drum roll in again. What they learned from their identification of Karabo’s last supper was that Karabo’s tribe, clan, group, family or travelling band ate lots of bark, stems and leaves from trees. Berger explains that these are nutritious and (apparently) tasty and, since they are the growing parts of the plant, they are, relatively speaking, bursting with food energy. This is opposed to the grasses growing on the ground that herbivores were eating. Now why does this matter? These folks had to eat something. But that’s the point.
It becomes part of a larger debate about whether these pre-human hominids were primarily arboreal – or if they lived mostly on the ground. And that, in turn, speaks to when, and in what order, the features that make us human (and distinguish us from apes) evolved. As evolution progressed – they didn’t come down out of those trees and proceed to live on the ground at that point. And if that is the case, they were evolving in areas where trees were abundant and in which they could live.
That, in turn, points to what is now the key evolutionary landscape: South Africa. And this in turn speaks about the evolving behavioural and evolutionary differences between Australopithecus and all those other evolving primates. Berger adds that now that science has got its, er, teeth into this hard evidence, it as if a curtain has been raised to reveal an entirely new landscape. From now on, palaeontologists will have to examine evolutionary developments for hominids as taking place in forests – and with a diet that comes from that environment.
In a way, this shouldn’t have come as the surprise it has, explains Berger. A moment’s contemplation of the present era’s great apes should have pointed scientists this way anyway, but many 20th century discoveries came from Kenya, Tanzania and Ethiopia and what had been the open, broken landscapes there and that shaped the way the scientists visualised the locales as evolutionary engines.
This all points to two other elements of what we are calling, in rough shorthand, the Berger method. Berger is a vigorous advocate of a return to the field, rather than simply relying on the laboratory for studies. Until very recently, for example, the actual extent of hominid (the broader ancestral trunk of all primates) and hominin (homo sapiens’ more direct ancestors) remains could easily be stored in the closets and cabinets of a snug office. Virtually all of the many exciting Southern African finds are now coming out of the limestone caves, where the remains probably were dragged there by predators or where the creatures fell to their deaths through holes.
Berger points out that there are enormous expanses of these dolomitic deposits – and those caverns that have formed in them over millennia – have yet to even be looked at cursorily. As a result, there are almost certainly vast numbers of fossilised remains waiting to be discovered, described scientifically and then fitted into what now seems like an increasingly complex lineage leading up to anatomically modern man. And across the globe – in central, eastern and South Asia and throughout much of Africa as well – there are even more such deposits that remain unexplored.
Berger walks across his office and then draws two diagrams on a nearby easel – one describes the way we used to think of the evolution of man – an ascending pathway from Homo habilis and Homo erectus through Australopithecus and on to anatomically modern man. Nice and neat, but not necessarily so, it seems. Then there is drawing number two. Instead of the neat line, this is a complex interweaving, like vines climbing around a central core. Berger explains we now think there were a great many variants that exchanged their genes along the way as evolution occurred, eventually generating the version of things we now know as us. With the impending explosion of new forms and fossils that we will come to know, we are only now beginning to get a grasp of the many forms of hominins and hominids we will sooner or later discover.
And this fits into Berger’s next point. South Africa now has an unparalleled opportunity to build on its internationally competitive base of experience to build a new international training effort to do the next steps. This will build on the ongoing revolution in palaeontology that is drawing upon many disciplines and experts from around the world – as all of these researchers communicate effortlessly via social media, email and the Internet. Research gains peer review from dozens of people – and the arguments about the evidence is thrashed out thoroughly and quickly – and delays in releasing the results of research can be collapsed from years or even decades down to months in many cases.
This can generate an increasing push for international fieldwork expertise, using the most modern techniques, capitalising on the vast and exciting expanse of work that lies ahead. And South Africa has that natural comparative advantage in this area, even if in prior decades such co-operation had been hamstrung by South Africa’s apartheid regime and its immediate legacy. Looking to the future, however, South Africa’s natural partners in much of this work will be Asian nations like India and China – where new discoveries lie in waiting, Berger explains.
To be a palaeoanthropologist, now, must be to live in a supremely happy time. Using these new techniques and networks of international co-operation to examine all the new evidence, it means being at a veritable ground zero of an explosion of knowledge in understanding in the origins of what makes us, well, us. DM
Stephen Hawking held a party for time travellers. He sent the invitation out the day after. Nobody attended.