Diet and status at Chalcatzingo: some empirical and technical aspects of strontium analysis

Determination of the levels of particular trace elements preserved in bone provides a potential pathway for reconstructing the diet of extinct primate species and archaic human groups. Strontium is one of the most useful trace elements for dietary reconstruction but several empirical properties of strontium must be considered during the interpretation of results. (1) Strontium is distributed unevenly throughout the physical environment. (2) Plants, in general, do not discriminate against strontium. (3) During ionic transfer across biological membranes, strontium is discriminated against by terrestrial vertebrates. (4) It is unlikely that strontium would be selectively removed from bone mineral during diagenesis. A particular difficulty in trace element analysis is caused by interaction between analytical technique and sample matrix. To assess this problem the skeletal population from Chalcatzingo was analyzed by two techniques: atomic absorption spectrometry and neutron activation analysis. The results from the two techniques compared favorably indicating that the pattern of bone strontium levels could be accepted as an accurate reflection of the distribution of bone strontium within the population. After demonstrating the internal accuracy of the results, the bone strontium level and position of social rank within Chalcatzingo were compared. Ethnographic and archaeological evidence on chiefdoms and states indicate that dietary differences in the amount of meat consumed occur between social ranks. The relative social ranks were reconstructed by using a "pattern analysis" of the burial goods accompanying each individual. The individuals accompanied by jade had the lowest mean bone strontium level (X = 532). Those individuals buried with a shallow dish had a slightly higher level (X = 635). A third group, which had no grave goods, had the highest mean bone strontium level (X = 700) which suggests that their diet contained less meat than was available to the rest of the community.

Imaginative Play in Pre-School Children as an Indicator of Emotional and Cognitive Development

Although imaginative play in children has long been of interest to psychologists it is only recently that it has become a topic for serious psychological research, largely through the groundbreaking work of J. Singer and his associates at Yale. In the present paper a summary of the major research focus on imaginative play is presented. Research outlining some of the correlates of the predisposition to imaginative play, studies linking imaginative play and creativity, the effects of the structure of toys and clinical applications are discussed.

A systematic assessment of early African hominids

A large sample of Pliocene fossil hominid remains has been recovered from the African sites of Hadar in Ethiopia and Laetolil in Tanzania. These collections, dating approximately between 2.9 and 3.8 million years ago, constitute the earliest substantial record of the family Hominidae. This article assesses the phylogenetic relationships of the newly discovered fossil hominids and provides a taxonomy consistent with that assessment. A new taxon, Australopithecus afarensis, has been created to accommodate these Pliocene hominid fossils.

Rehabilitation of the disabled: the role of social networks in the recovery process

This study examines the role of formal and informal intervention systems utilized by the chronically disabled in the process of rehabilitation and recovery. In addition to formal community resources (agents and agencies), the disabled tend to rely on informal social networks (family and peers) as sources of support in the recovery process. The findings presented in this paper focus on the extent to which formal interventions and informal resources are supportive for the disabled and the effect of these support systems on outcome. The analysis is based on empirical data derived from a survey of 950 chronically disabled adults interviewed in a metropolitan community in the U.S.A. Among other findings, the evidence suggests that informal social networks play an important role in the rehabilitation of the disabled. Reliance on informal resources is enhanced in the absence of formal rehabilitation intervention, suggesting alternative modes of social support are actively sought and utilized by the disabled. Furthermore, lay-initiative may constitute another effective resource in the process of recovery. These findings suggest that informal resources are effectively utilized by the disabled, but are not usually identified as part of the formal intervention system in the community.

Finger ridge-count variability in sub-Saharan Africa

Mean finger ridge-count data were obtained, primarily from literature sources, for 31 male and 24 female sub-Saharan African samples. The 10 finger ridge-counts and total ridge-count were used as independent variables in a multiple regression analysis, latitude and longitude serving in turn as the dependent variables. The results show that it is not the magnitude of the ridge-counts themselves that is important, but rather contrasts between groups of digits. The most important geographically patterned variation in ridge-counts consists of contrasts between digits 4 and 5 and digits 2 and 3. South and south-east African populations are characterized by low contrasts, west Africans by high contrasts and, south-west Africans are intermediate. The geographical patterning of the contrast agrees well with known patterns of gene flow into and within the continent as determined by serological genes. Principal components analysis was also carried out to determine whether within-group components corresponding to the geographically relevant between-group variation could be identified. The third, fourth and fifth components drew the same types of contrasts between the groups of digits identified in the multiple regression analysis, but they were relatively unimportant. The geographically important principal components would have been overlooked in a traditional multivariate analysis of finge ridge-counts, since the analysis would have been dominated by pattern size. We conclude that finger ridge-counts are potentially very useful in population studies, but account must be taken of their multicomponent nature.

The femur in early human evolution

Uni- and multivariate analyses of 5 fossil and 215 extant hominoid femora show that two morphological patterns of hominid femora existed about two million years ago. Femora classified as Homo sp. indet. (KNMER 1472 and 1481) are more like Homo sapiens although not identical. Those classified as Australopithecus robustus (SK 82 and 97) and A. boisei (KNM-ER 1503) are similar to one another but uniquely different from any living hominoid. The strong mophological constrasts imply biomechanical and possible locomotor differences, although these are as yet unknown.

The role of kin-structured migration in genetic microdifferentiation

Most current models of human population structure view migration solely as a deterministic force reducing the variance in gene frequencies among the local colonies of a subdivided population. By an empirical example and through simulation experiments, it is shown that migration structured along kinship lines (by analogy to the lineal or 'kinship' effect) does not always reduce the variances of gene frequencies arising through intergenerational random genetic drift. Thus populations experiencing high rates of migration may not be genetically homogenous.

The theory of encephalization

The theory of encephalization is developed from elementary dimensional requirements for the construction of a brain of given size. The basic assumption in the theory is that most of the brain in vertebrates is constructed as a series of mappings repeated at various levels. Encephalization is seen as a composite of an amplification factor for the repeated mappings (identical with the encephalization quotient EQ) and a factor associated with "added" tissue. The latter may be viewed as tissue that corresponds to new functions. The relation of the theory to allometric analysis is a relationship of theory to empirical estimation of "expected" brain size at a given body size. But body size is not fundamental to the theory. It is merely one of several possible sources of a measure of the area of a basic mapping, as it were, which is then subject to the amplification factor. Issues in the use of encephalization to assess behavioral capacities are reviewed briefly, as are the neurobiological correlates of encephalization and brain size.

Cultural adaptability as an attribute of therapies: the case of Morita psychotherapy

Morita psychotherapy, a form of therapy developed in Japan some sixty years ago, has survived extensive changes in Japanese society, and is now enjoying popularity in the United States. This gives us an opportunity to look closely at the concept of 'cultural fit' between an important therapeutic technique and its social milieu, and to speculate about recent changes in American culture that may account for the growing popularity of Moritism. In contrast to Western style 'talking therapies' like psychoanalysis, Morita psychotherapy is relatively group-centered, ritualistic, and behavioristic. On would expect to find these features in a Japanese therapy, but their acceptance in America suggests that previously popular Western techniques may not be optimum for handling certain problems of the post-industrial American. McLuhan, Peacock, Douglas, and others have suggested some emerging traits of Western character that might shed some light on this question.

Physical variation and history in Melanesia and Australia

Local biological variation is marked in Melanesia. Some of it may result from gene flow from Micronesia, but the essential variation appears to result from isolation due to social fragmentation, and to genetic drift in place. In different regions, the variation may correspond well with language relationships, and probably constitutes differentiation which has been preserved over a considerable period, especially since the arrival of horticulture and development of village farming. However, none of this patterning suggests distinct waves of migration into Melanesia. Variation among Australian aboriginal groups is smaller, though far from absent. It may reflect a hunting culture together with social customs allowing more intertribal marriage than is typical of Melanesia. While phenotypically Australians and Melanesias differ, cranially they are closely allied, as against other major human groups. It is suggested that the genetic and phenotypic variety is old, that it existed in the previous home of the Australo-Melanesians (Old Melanesia, comprising present Indonesia and the Phillipines) at least back to 40,000 years ago, and that much of the variation in Melanesia and Australia, including their differences, results from the sampling process involved when different groups out of the original populations made early corssings of the water barriers from Old Melanesia.

Archeology, population genetics and studies of human racial ancestry

Using traditional classification, many people have tried to determine the place and time of origin of the major human races. Two basically conflicting views have prevailed, one asserting that races developed as local variations in a species evolving phyletically over much of the Old World for up to one million years, and the other view holding that present races are local variations on populations recently expanding into most areas and replacing the previous hominid inhabitants, this occurring since the time of the Neanderthals. Both views are based on the same archeological data. Gene frequency data and time-calibrated genetic distance measures have recently been applied to this problem. Here we show that the probable demographic nature of Pleistocene populations has obscured genetic distances to such an extent that they cannot be used to discriminate between the two viewpoints of racial origins. The racial classifications themselves are probably not useful in this context and obscure the question, so that we presently do not have a scientifically valid understanding of racial origins.

Fossils and the mosaic nature of human evolution

These new fossils, dates, analyses, and interpretations lead to confirmation and refinement of the mosaic scheme of human evolution as proposed by early evolutionists such as Lamarck, Haeckel, and Darwin. Evolutionary changes in the body adapting our ancestors to bipedalism occurred before 3 million years ago, judging by the completeness of the adaptation in the late Pliocene-early Pleistocene hominids. The skeletons of these early hominids were not identical to those of modern humans, but locomotor behavior was probably human. At about 3 million years ago their brains were relatively small, although internal reorganization may have been taking place. By 2 million years ago a wider range of variation in brain size appears in the fossil record, with an average size somewhat larger than that in earlier hominids. Concomitant with this beginning of brain size increase was the reshaping of the pelvic region, perhaps related to an increase in birth canal size to accommodate larger-brained fetuses. Evidence for tool manufacturing, meat eating, shelter building, and probably food sharing also occurs at about this time, which signals the coming of a new adaptive strategy.

Hominid teeth and their relationship to hominid phylogeny

Hominid fossil teeth are analyzed in terms of size and shape and contrasted with teeth from a modern population to determine boundaries that can be placed on a reconstruction of the hominid phylogeny. Teeth alone are considered as they are the only material preserved in large enough quantities to measure population variability accurately. Problems with the use of indices such as size and shape as species markers are discussed. Conclusions that are made about possible phylogenies are based on the analysis of size and shape.

La cultura negra del Litoral Ecuatoriano y Colombiano: un modelo de adaptación étnica

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