Palaeoanthropology and the Evolutionary Place of Humans in Nature

Abstract

Palaeoanthropology, the study of the fossil evidence for human evolution, remains a highly contested field. New discoveries are continuously being used to promote alternative models as well as to propose new candidates for our ultimate ancestor. The fossil evidence has increased over the years, and has been supplemented (and often challenged) by molecular data drawn from living people and the great apes. As recently as the 1980s, palaeoanthropologists proposed that human roots stretched back into the Middle Miocene, between 17 and 8 million years ago. Then the earliest true hominids or human ancestors became the South African australopithecines, who are less than 5 million years old. Now there appears to be a tremendous variety of early humans at all stages of their evolution. Along with this new research on the basal hominids has been a renewed interest about what it means to be Homo sapiens. Molecular and fossil data shows that Africa was also our homeland, and that all people today are descended from a small founder population in existence there between 50,000 and 200,000 years ago. Every human society has stories about their past, myths and legends that explain who they are, and how they came into being. These accounts are conditioned by history and experience, and the collective behaviors that anthropologists study as part of culture. What we call "science" offers explanations, which can also be conditioned by cultural values, attitudes and beliefs (Cartmill, 1993, 2003; Landau, 1991; Lewin, 1987). But science is separated from story telling and myth, one is told, because it is done within a framework that requires empirical evidence that can be supported or falsified. In many so-called hard sciences, assumptions can be tested experimentally. Variables are defined, placed in certain situations, and then their interactions can be directly observed. Alter the variables and the result may or may not change. The historical sciences are different. What is being studied is the past, something that has already happened, which cannot be recreated in nature or in a laboratory. Rather than worrying about "physics envy" (Gould, 1981, p. 113), some historical sciences are beginning to learn how to live within these restrictions. Palaeoanthropology is one of these historical sciences. It is the multi-and interdisciplinary study of human origins and evolution. The facts in palaeoanthro-pology are fossil human bones and their context in time and space. These are generally referred to as hominids or hominins, common names for the Linnaean biological Family Hominidae or Tribe Hominini, respectively. This distinction depends on how one sees our closest living nonhuman relatives, the African apes. Originally placed in Family Pongidae, along with the orangutan (genus Pongo), chimpanzees (Pan) and gorillas (Gorilla) are genetically more similar to humans, something that should be reflected in taxonomy. So many classifications only distinguish African apes and humans at the tribal levels, just above the genus.