Physical anthropology, often referred to as biological anthropology, is the scientific discipline studying human beings from a biological and evolutionary perspective. This field investigates what it means to be human by exploring our origins, variation, and adaptations across time and space. As one of the four main subfields of general anthropology, alongside cultural anthropology, archaeology, and linguistic anthropology, it provides a deep-time perspective on the human species. Biological anthropology uses the scientific method to examine our entire biological history, from the earliest ancestors to the diverse populations living today.
Tracing Human Evolution
A major focus within biological anthropology is paleoanthropology, the study that reconstructs the evolutionary pathway of the human lineage. Paleoanthropologists examine the fossilized remains of hominins, spanning a period of roughly six million years. The analysis of skeletal remains, teeth, and footprints provides direct evidence of major evolutionary shifts. For instance, the transition to bipedalism, or walking upright on two legs, is documented through changes in the pelvis, femur, and foot bones of species like Australopithecus afarensis.
This work also explores the development of our distinctive large brains and the emergence of tool-making capabilities. Tools found in archaeological contexts, sometimes dating back over 2.5 million years, are analyzed alongside hominin fossils. This analysis helps researchers understand changes in dexterity, cognitive ability, and diet. By piecing together this physical evidence, researchers can chart the long-term changes that ultimately led to the appearance of Homo sapiens.
Studying Our Living Relatives
Biological anthropology relies heavily on primatology, the subfield focused on the behavior, anatomy, and ecology of non-human primates, including monkeys, apes, and prosimians. Studying our closest living relatives, such as chimpanzees and gorillas, offers a comparative framework for interpreting the fossil record and understanding the origins of human traits. Researchers observe these animals in their natural habitats to document complex social structures, communication methods, and tool use.
Primatologists identify shared ancestral traits and uniquely human adaptations. For example, the extended period of juvenile dependency and the complexity of social learning seen in great apes offer insights into the evolutionary roots of human childhood and culture. Common physical characteristics, like grasping hands and binocular vision, represent a shared anatomical legacy. Observing the ecological adaptability of primates in diverse environments helps model how our own ancestors might have responded to changing landscapes.
Understanding Modern Human Adaptation
The study of contemporary human biological variation explores how our species has adapted physiologically and genetically to different global environments. This research integrates population genetics to track the spread of specific traits through human groups over recent generations. For instance, the ability to digest lactose into adulthood, known as lactase persistence, evolved independently in several populations with a history of dairy farming.
Physiological responses to environmental stressors reveal mechanisms of plasticity. Populations living at high altitudes, such as those in the Andes or on the Tibetan Plateau, show unique adaptations, including larger lung capacities and different hemoglobin concentrations, to cope with lower oxygen levels. Skin pigmentation is another classic example, with variation following a clinal distribution that correlates with levels of ultraviolet radiation. This focus demonstrates that human diversity is a spectrum, directly challenging outdated concepts of fixed, distinct biological “racess.”
Applied Biological Anthropology
Biological anthropology has practical applications, primarily through forensic anthropology and bioarchaeology. Forensic anthropology involves the application of skeletal analysis techniques to medicolegal contexts, such as identifying human remains in criminal investigations. Forensic specialists determine a biological profile, which includes estimating age at death, sex, ancestry, and stature from skeletal features.
Bioarchaeology focuses on the analysis of human skeletal remains recovered from archaeological sites to reconstruct the lifeways of past populations. This involves looking for evidence of ancient health, disease, and diet through the wear patterns on teeth and the presence of paleopathology. Both fields share a common methodology rooted in osteology, the study of bones, but differ in their temporal focus—bioarchaeology on historical populations and forensic anthropology on modern cases. Knowledge gained from one discipline often enhances the analytical capabilities of the other.