Paleoanthropology is a multidisciplinary approach to exploring the evidence for the evolution of humans and their fossil ancestors. Paleoanthropology explores human anatomical structure, archaeological remains, habitat, and chronology through the diverse disciplines of biological anthropology, primatology, archaeology, ecology, geology, paleontology, biology, genetics, and cultural anthropology. In exploring the question of human evolution, paleoanthropologists link ideas through evolutionary theory, comparative anatomy, environmental and cultural influences on behavior, and geological time.
History of Paleoanthropology In the 1860s, only a few pre-modern fossils had been found; scientists did not agree upon their identification or age, let alone upon the model to explain human evolution. Charles Darwin had just published On the Origin of Species in 1859 on natural selection as a mechanism to explain evolutionary change through time. Few people yet realized the extent of the antiquity of humanity.
On the European continent, most people subscribed to the school of Catastrophism, led by the writings of French paleontologist Georges Cuvier. According to Cuvier, fossils found in different geological strata illustrated successive revolutions, during which all living things were destroyed and replaced by new forms. Cuvier and his supporters were unwilling to accept early ideas of evolution, and did not believe in the existence of human fossils. In Britain, the prevalent school of thought was Uniformitarianism, led by James Hutton and Charles Lyell. Uniformitarianism held that natural processes observable today were responsible for the gradual modification of the earth. Proponents of this view believed that the earth was at least several millions of years old. The Uniformitarian position set the stage for the relatively quick acceptance of Darwin’s work and the theory of evolution as a whole.
The idea that humans had evolved from an apelike creature was not problematic for proponents of Uniformitarianism. Many perceived a gradual evolution of humans from a form of anthropoid ape. As more fossil hominid forms were unearthed, such as the Spy Neandertals from Belgium, people began to search for the “missing link” between apes and humans. Ernst Haeckel suggested that there should have been a completely transitional form between apes and humans, one that was neither ape nor human. Paleoanthropologists of the mid- to late-19th century focused primarily on description and typology, organizing fossils into successive evolutionary stages and racial categories. This temporal and typological sorting of fossils (and living people) did little to explain why and how humans evolved in the patterns they did.
In the 1930s a movement began to form a synthetic theory of evolution, combining genetics, evolutionary theory, and populational studies into a single perspective, known subsequently as “The Modern Synthesis.” It rejected the descriptive, typological emphasis commonly practiced in zoology and physical anthropology up until that point. By the early 1950s, this major paradigm shift had a most profound effect on American biological anthropologists. Researchers began to focus on ecological change and cultural behavior as factors in human evolution. Today, paleoanthropology as a research focus spans a broad range of topics and disciplines.
The Paleoanthropological Approach
Paleoanthropology differs from paleontology in that it primarily studies human origins; because of this, the application of some of the standard tools used by paleontologists can be problematic. Early fossil humans, like other animals, were subject to evolutionary forces such as natural selection, and had to adapt biologically and behaviorally to specific environments or ecological niches. When fossil humans began to rely on cultural adaptations to assist them in survival, biocultural feedback created a cultural buffer between hominids and their environment. Because of this, there is considerable debate over what types and levels of selective forces can be used to predict fossil human life ways. Dietary habits, advanced cognitive abilities, communication and language skills, and technological sophistication all played a role in shaping human adaptation to the environment, making the concept of the ecological niche, and even natural selection, less useful as a research tool.
Paleoanthropology in the Field
Like most fossils, human fossils are rare and difficult to find. As a result, fieldwork is an important part of paleoanthropology. Early fieldwork, such as that conducted by Robert Broom or Louis and Mary Leakey, was a small-scale effort by one or two individuals and their hired crew. These individuals were experts in some areas, such as excavation or anatomy, and called in experts on key questions such as fossil species identification or interpretation.
Today, while one individual still leads a field project, there has been a shift in focus toward a team approach. This interdisciplinary approach, first championed by F. Clark Howell, encourages collaboration among an international team of specialists, representing many fields of study.
Biological anthropologists examine fossils for anatomical features of hominids using their knowledge of comparative primate anatomy and biomechanics. Geologists help to locate potential human occupation sites by examining maps, aerial and satellite photography, and the stratigraphy of a region. They also help to develop a dating sequence for the region. Paleontologists estimate the age of the site through a comparison of fossil animals, or fauna, in other nearby sites. Reconstructing past environments, or paleoenvironments, involves cooperation from paleontology as well as ecology, paleobotany, palynology (fossil pollen grains), and geomorphology (water, land features). Archaeologists recover material cultural remains from human behavior and can provide dates for the site based on features of the artifact’s style, location, and raw material.
Paleoanthropology in the Lab
While fossil recovery and description are important (without which there would be no fossils to study), equally important are the research questions these fossils can help answer. Like all fields of science, paleoanthropology relies upon the scientific method of inquiry, hypothesis formation and testing. Through the collaboration of researchers from many fields, paleoanthropologists examine the broader picture of human origins through developing competing phylogenies, or evolutionary trees, which reconstruct possible relationships between fossil species. These phylogenies are tested against the fossil record and refined with new discoveries or interpretations. Among the key research questions asked by paleoanthropologists are:
- How, when, and where did modern humans evolve?
- When did bipedalism evolve, and why?
- When and why did tool-making develop, and who were the first toolmakers?
- What is the ancestor of the genus Homo?
- How many fossil species of hominids existed?
- How did the modern human brain evolve, and why?
- How did the human capacity for language evolve, and why?
- How and when did modern humans become so diverse?
These questions, approached using many lines of evidence and fields of study, guide our understanding of human origins and our unique adaptations.
References:
- Institute of Human Origins, Arizona State University. (2005). Retrieved January 10,2005 from
- Johanson, D., & Edgar, B. (1996). From Lucy to Language. New York: Simon and Schuster.
- Wood, B. (2004). Human evolution: A very short introduction. Oxford: Oxford University Press.
