Thirty-Five Years of Paleoanthropology

When we published our first joint paper on human evolution back in early 1975 (Eldredge and Tattersall 1975), the world of human evolution was a very different place. For a start, it was populated by a much smaller cast of characters. Not only was paleoanthropology itself a much tinier enterprise than it is today, but the sum total of hominid fossils known was hugely smaller. The riches of the Turkana Basin in northern Kenya had only just begun to be explored. The iconic fossil “Lucy” had yet to be found in Ethiopia, and indeed, the Hadar area from which she came had only just been recognized for the palaeoanthropological treasure trove it has turned out to be. Now near-mythic names such as Atapuerca in Spain and Dmanisi in Georgia were yet to become part of the paleoanthropological vocabulary. And such lesser but nonetheless significant names as Ceprano, Drimolen, and Buia had still to fall even on professional ears. Yet even more foreign to modern eyes than the small fossil pond—today we can no longer complain about an “inadequate” human fossil record, much as we’d like to have more—was the prevailing way of looking at the human evolutionary story. Back in the 1970s, the view of the hominid fossil record was fairly unrelentingly minimalist. Under the sway of the Evolutionary Synthesis as it was imported into paleoanthropology in the early 1950s, students of human evolution generally sought to minimize the diversity they perceived in the known record. A single lineage struggling like a green tendril toward the light was the preferable view, and even though by the late 1960s discoveries in Kenya had rendered the strictest version of this model untenable (the “robust” australopiths had to be recognized as a side branch), there was still a general desire to simplify the picture as much as possible. This was, of course, an example of what might be called “human exceptionalism”: Since there is undeniably only one species of human on the planet today, there is an understandable desire to reconstruct our phylogeny by projecting Homo sapiens back into the past through a chain of increasingly primitive extinct species. And although among primates (and mammals) in general there is an unmistakable signal in the fossil record as well as in the modern fauna of diversity— successful forms tend to become more diverse, not to strive toward a particular goal—hominids were regarded as an exception because they possessed culture, an elusive expression of behavioral complexity that “broadened” their ecological niche to the extent that no more than one species of our kind could exist at any one time. When we began our joint investigations of human evolution in the early 1970s, the “cladistic revolution” was in full swing at least in certain corners of the American Museum of Natural History, where we both worked. And we were both highly sensitive to zoological diversity, one of us as a student of trilobites, a highly varied group of Paleozoic invertebrates, and the other as an aficionado of the lemurs, an insular group of primates inMadagascar that has diversified to an astonishing degree. We were hardly surprised, then, to find that the hominid fossils we looked at did not conform to any of the more or less linear views of human evolution that then prevailed. In particular, the cladogram we came up with (to I. Tattersall Division of Anthropology, The American Museum of Natural History, Central Park West at 79th St., New York, NY 10024, USA