Biological Anthropology;5 Facts You Must Know

Biological anthropology comprises five general sub-disciplines: human evolution, primatology, human genetics, the study of human physical growth, and human ecology. The first two subdisciplines have sometimes been termed †‘physical anthropology’ in contrast to the second three as ‘human biology’; ‘biological anthropology’ embraces both. The field has been grounded in the natural sciences and medicine rather than social studies, which on their own have been thought not to provide the requisite biological competence (Harrison 1964). Despite numerous assertions of the need to integrate these various sub-disciplines with *archaeology, social anthropology and associated social science fields, in practice few have succeeded in this aim since *Franz Boas.

Evolutionary studies in biological anthropology have focused on establishing the taxonomic (classificatory) and phylogenetic (evolutionary) relationships between fossil and living primates. In theory, phylogeny provides the necessary basis for taxonomy; but in practice, preliminary phylogenies can permit taxonomy to proceed. The method of cladistic taxonomy, which has become widely used, proceeds by first demonstrating primitive and derived characteristics of the members of a group, and then determining the derived characteristics shared among them (Groves 1989).

The term ‘hominid’ refers to populations and species with which Man shares an evolutionary history excluding any other living primate. The hominid lineage is thought to have evolved between five and ten million years ago. Studies of hominid evolution have attempted to explain where, how and why the human species evolved, hence a longstanding preoccupation with relationships between fossil hominids and their only surviving subspecies Homo sapiens sapiens (Foley 1987). However, the coexistence in the fossil record of species of Australopithecus and Homo indicates that the study of hominid origins is not to be equated with that of human origins (Lewin 1993).

These studies have an historical basis in the comparative anatomy which flourished in the eighteenth century. Their development was greatly influenced by the nineteenthcentury works of †Charles Darwin and †T.H.Huxley which sought to take the study of Man away from theology and bring it within the scope of natural history. Their more distant intellectual origins are sometimes sought in the works of Aristotle. The advent of statistical techniques introduced by Quetelet, Galton and Pearson in the late nineteenth and early twentieth centuries enabled biometric approaches to become sophisticated (Boas [1911] 1938; Barnicot in Harrison 1964; Aiello 1992). A major problem has been separating the anatomical variation characteristic within a species from that expected between species. The use of functional anatomy and environmental physiology, and of comparison between the fossil record and field studies of extant primates in their social and environmental context, has allowed questions such as ‘Why are humans bipedal? Why hairless? Why human?’ to be asked and in some respects answered. Several competing phylogenies have been proposed and remain controversial.

For a large-bodied primate, the human shows a relatively large brain and a long period of childhood dependence. Various theories of nutritional constraints on the origins of these properties have been proposed. Some physical properties may take their form and size purely as a function of body weight. Allometry is a method of comparing animals by scaling features according to body size, and has therefore been an important tool in the analysis of primate relationships. It has been used to argue the central importance of energetic constraints on brain development in determining peculiarly human characteristics (Martin 1983). The origins of the hominid adaptation of parental provisioning of offspring, extended dependency during childhood and large body size, have been sought in meat-eating, hunting or scavenging, and tool use. Studies of dental development suggest that an extended childhood was not present in the Australopithecines or Paranthropines. However, the nature and extent of meat acquisition and consumption in hominid evolution is a matter of controversy (Ulijaszek and Strickland 1993). The human species has often been distinguished from others on the grounds of *language, which is itself construed to be essential to *‘culture’ as a non-biological trait. Theories of the evolution of language are therefore of great importance. It has been argued that language origins lie in cognitive abilities rather than in properties of nonverbal communication (gesture/call) which are shared by all primates (Burling 1993). However, there may also be advantages of social lubrication which are afforded by grooming behaviour in non-human primates.

Biological Anthropology;5 Facts You Must Know

Human genetics

The Darwinian theory of evolution by natural selection has been central to the development of biological anthropology. Early workers tended to explain human diversity in terms of migrations and intermixtures. Mendelian (particulate) inheritance of some features was postulated by showing that the variability of quantitative characters in groups of mixed parentage was greater than that of each parental group (Boas [1911] 1938). It was not until immunological and biochemical methods enabled identification of blood groups, abnormal haemoglobin variants, and enzyme polymorphisms that particulate inheritance of such specific traits could be demonstrated (Barnicot, in Harrison 1964). The study of genetic variation within and between human populations, and that of processes of natural selection through effects of isolation, migration and differential reproductive success, have become well established. For example, the changing prevalence of non-insulin dependent diabetes in Polynesians has been attributed to the effects of selection against a genotype which, under less affluent conditions, would have had energy-conserving advantages.

A fundamental question has been the degree of interaction between genetic and environmental sources of human biological variation. This has been investigated for many characters, including stature, obesity, the milk-sugar digesting enzyme lactase, types of muscle fibre, and IQ. However, the method of comparing identical twins reared together with those reared apart does not adequately separate variation due to genetic inheritance from that attributable to non-genetic inheritance, and tends to overestimate the genetic contribution. Other statistical methods attempt to overcome this problem (Shephard 1988). At the sub-cellular level, the conventional distinction between genetic and environmental sources of phenotypic variation is hard to maintain. There is a growing literature on the ways in which nutrients and genes interact to influence gene expression. The ability to identify individuals by their genetic profiles is useful in forensic investigations.

The sub-discipline of forensic anthropology has used a variety of methods of DNA fingerprinting. It has therefore had an important role in public practice, and enabled the determining of relationships between ethnic groups. Mitochondrial DNA is inherited through the maternal line and comparison across populations suggests their degree of genetic relatedness. On this basis, relationships between genetic and linguistic classifications of human groups have been examined. The method has also been used to argue that Homo sapiens sapiens originated in Africa rather than in different regions of the world. In many societies, marriage between close †consanguineous relatives is expected to occur, for example between first cousins or between uncle and niece.

This has raised questions about the genetic consequences of such marriage patterns and their implications for health. Some studies have reported a high incidence of congenital malformations and post-natal mortality in the offspring of such unions in South Indian groups. Such marriage patterns may be linked to social controls over property and its inheritance. Studies have also been made of assortative mating for social economic or anthropometric characteristics, and of the relationship between such traits and reproductive success

Leave a Comment