Antiquity and Social Functions of Multilevel Social Organization Among Human Hunter-Gatherers

Three levels of social organization are recognized among human hunter-gatherers: the community, the domestic unit, and the band. We describe the key features of these three levels and show how they are intimately connected. We hypothesize that, in the course of human social evolution, bands emerged as a level of social organization within existing communities. As predators, hunter-gatherers live at lower population densities than chimpanzees (Pan troglodytes), even where the two species are sympatric. We propose that band formation evolved in humans from the more transient fissioning behavior seen within chimpanzee communities as a solution to the conflicting pressures of sustaining higher levels of cooperation required in hunting and the division of labor in a more dispersed community. If disputes break out, or if resources in the band territory are temporarily depleted, the existence of a wider community continues to be adaptive. To reconstruct the evolution of band society, we draw upon four lines of evidence: group (or network) size predicted from neocortex ratios, the distance materials were moved from their source during various periods in hominin evolution, ethnographic data on hunter-gatherer daily foraging ranges and population densities collated by the authors, and fossil hominin morphology. From these data, we conclude that key features of modern human hunter-gatherer social organization probably appear in the course of the evolution of Homo heidelbergensis.     

Hormones and Paternal Behavior in Vertebrates

This review examines the influence of hormonal stimulation onpaternal care in selected species of fish, birds and mammals.Correlational studies of hormonal changes and the occurrenceof paternal behavior as well as experimental studies are considered.Understanding the influence of hormones on paternal behavioris complicated by whether the species studied shows maternal,paternal or biparental care and by the interactions among hormonalchanges, prior experience and responses to external stimuli.It is evident that hormonal changes may be the result as wellas the stimulus for paternal care and that stimuli from nests,eggs and young may be important for inducing the hormonal conditionswhich maintain paternal care. Hormonal determinants of sexualdifferentiation and the neuroendocrine control of paternal behaviorare discussed. Although there are few theories which includethe role of hormones in paternal care, some hypotheses relatingto the "association hypothesis" of Gross and Shine (1981) areconsidered and suggestions are made for future studies.     

Evolution of Active Neurohypophysial Principles Among the Vertebrates

Nine active neurohypophysial peptides have been identified amongthe vertebrates. Arginine-vasotocin appears to be the most primitive.It occurs in cyclostomes and among representative species fromall major branches of vertebrate phylogeny. The eight otherneurohypophysial principles are presumed to have evolved fromarginine-vasotocin after one or more reduplications of the primitivearginine-vasotocin gene. Argininevasotocin cannot be detectedin the adult mammalian neurohypophysis but it has been foundin the pineal and subcommissural organs of adult mammals. Arginine-vasotocinmay be released into the cerebrospinal fluid and influence functionsmediated by hypothalamic hypophysiotropic factors. The primitivefunctions of arginine-vasotocin are not clear. They may relateto cardiovascular regulation since vascular responses to arginine-vasotocincan be demonstrated in species representing all major branchesof vertebrate evolution.     

The Evolutionary Emergence of Vertebrates From Among Their Spineless Relatives

The evolutionary origin of vertebrates has been debated ad nauseam by anatomists, paleontologists, embryologists, and physiologists, but it is only now that molecular phylogenetics is providing a more rigorous framework for the placement of vertebrates among their invertebrate relatives that we can begin to arrive at concrete conclusions concerning the nature of ancient ancestors and the sequence in which characteristic anatomical features were acquired. Vertebrates tunicates and cephalochordates together comprise the chordate phylum, which along with echinoderms and hemichordates constitute the deuterostomes. The origin of vertebrates and of jawed vertebrates is characterized by a doubling of the vertebrate genome, leading to hypotheses that this genomic event drove organismal macroevolution. However, this perspective of evolutionary history, based on living organisms alone, is an artifact. Phylogenetic trees that integrate fossil vertebrates among their living relatives demonstrate the gradual and piecemeal assembly of the gnathostome body plan. Unfortunately, it has not been possible to demonstrate gradual assembly of the vertebrate body plan. This is not because vertebrates are irreducibly complex but because many of the characters that distinguish vertebrates from invertebrates are embryological and cellular and, therefore, inherently unfossilizable.

Action Potential Energy Efficiency Varies Among Neuron Types in Vertebrates and Invertebrates

The initiation and propagation of action potentials (APs) places high demands on the energetic resources of neural tissue. Each AP forces ATP-driven ion pumps to work harder to restore the ionic concentration gradients, thus consuming more energy. Here, we ask whether the ionic currents underlying the AP can be predicted theoretically from the principle of minimum energy consumption. A long-held supposition that APs are energetically wasteful, based on theoretical analysis of the squid giant axon AP, has recently been overturned by studies that measured the currents contributing to the AP in several mammalian neurons. In the single compartment models studied here, AP energy consumption varies greatly among vertebrate and invertebrate neurons, with several mammalian neuron models using close to the capacitive minimum of energy needed. Strikingly, energy consumption can increase by more than ten-fold simply by changing the overlap of the Na⁺ and K⁺ currents during the AP without changing the APs shape. As a consequence, the height and width of the AP are poor predictors of energy consumption. In the Hodgkin–Huxley model of the squid axon, optimizing the kinetics or number of Na⁺ and K⁺ channels can whittle down the number of ATP molecules needed for each AP by a factor of four. In contrast to the squid AP, the temporal profile of the currents underlying APs of some mammalian neurons are nearly perfectly matched to the optimized properties of ionic conductances so as to minimize the ATP cost.     

Social Organization and Knowledge

This paper explores the relationship between different types of social organization, on the one hand, and different modes of knowing and types of knowledge, on the other. Some characteristic distinctions are suggested and supported with evidence, both from diverse areas of theory, and from the study of two contrasting Melanesian cultures: that of the Lavongai of New Hanover and the Tikana of New Ireland.     

Detection of Sperm Histone Diversity Among Vertebrates by Alkaline Fast Green Staining

Testis sections from fifteen species from six classes of vertebrates were stained with alkaline fast green (AFG) to correlate staining differences with the known biochemical diversity of histones in the spermatozoa. After trichloroacetic acid (TCA) hydrolysis the sperm of some species known to contain sperm-specific histones did not stain. This correlation held if fixation in neutral buffered formalin was limited to 3 to 6 hr and hydrolysis was done at 90 C. The species whose sperm did stain after TCA hydrolysis could be divided into three groups. In some species the sperm no longer stained if, after TCA, the sections were treated with thioglycollic acid. These sperm contained basic proteins that were rich in cysteine. In turn, the group of species whose sperm continued to stain after TCA and thioglycollic acid treatments could be subdivided. The sperm of some were stained specifically without DNA hydrolysis if the AFG was made up with sodium chloride. These sperm contained sperm-specific histones. In other species the sperm did not stain under these conditions, and these sperm had a basic protein complement similar to that found in somatic cell nuclei. These correlations suggest that AFG staining can be used to detect sperm histone diversity in a wide range of organisms.     

Intracellular Organization: Evolutionary Origins and Possible Consequences to Metabolic Rate Control in Vertebrates

We adopt the position that metabolism originated at (or near)mineral surfaces prior to the origin of the first cells. Basedon current views of the organization of contemporary animalcells we speculate that the metabolism of the immediate ancestorsof eukaryotic cells required these non-biological surfaces,but that the latter were subsequently replaced by membranes,and nuclear and cytoplasmic matrix proteins which, we argue,remain as required participants in the intermediary metabolismof contemporary eukaryotic cells. The idea that such an lntracellularorganization could have provided a fundamental means by whichto control metabolic rate at the level of the intact animalis considered next. In the case of vertebrates we suggest thatthe organismic level of control might operate throughthe rateof capillary blood flow, as proposed in the Flow Theory of Coulson(1986): by controlling the rate at which the organized enzymearrays within the cells are perfused with substrate, cellularmetabolic rates could be set throughout the organism in an integratedfashion. Although there are problems with this linkage the interestingpossibility arises that the metabolic rate of individual cellsmay be subservient to the organism, being driven not so muchby the well known intracellular controls of concentration-based-biochemistryas by the flow of nutrients through the cells.     

Community Organization Among Neotropical Nectar-Feeding Birds

Assemblages of neotropical hummingbirds are organized accordingto parameters of available resources and morphological-behavioralattributes of particular hummingbird species. We distinguishfive types of flowers relative to hummingbird foraging, andwe define six community roles for hummingbirds in exploitationof various flower types. These roles are: high-reward trapliners,which visit but do not defend nectar-rich flowers with longcorollas; territorialists, which defend dense clumps of somewhatshorter flowers; lowreward trapliners, which forage among avariety of dispersed or nectar-poor flowers; territory-parasitesof two types (large marauders and small filchers); and generalists,which follow shifting foraging patterns among various resources.Simple communities on islands usually contain one species oflow-reward trapliner or generalist and one territorial species,and sometimes support one high-reward trapliner; often thesespecies are sexuallydimorphic. More complex mainland communitiessupport varying numbers of species in different roles, dependingon the relative importance and constancy of different flowertypes. High-reward trapliners are particularly important inforest under-stories, while forest canopies and open habitatssupport large numbers of shorter-billed, mobile birds fillingthe other five roles. We conclude by pointing out the many parallelsthat exist with other consumer groups.     

German-Russian Catholic Social Organization

Abstract

The 18th century German agrarian village system has persisted on the plains of western Kansas as a consequence of a Roman Catholic centered social system. The acculturation process has been retarded by the centripetal forces of church, village, and kinship identities.     

Male Cheetah Social Organization and Territoriality

Patterns of territory ownership in male cheetahs inhabiting the Serengeti Plains are described, and factors affecting territorial behaviour are examined. Body size and age were factors influencing whether males became territorial, and single males usually had to join up with others in order to oust residents. Both size of male coalition and body size of its members were associated with length of tenure on territories. Limited data suggest that territory owners were probably no more likely to encounter females than were non-territorial males but there was a suggestion that they suffered lower survivorship costs than non-territorial males.     

Fate and Fortune in Rural China: Social Organization and Population Behavior in Liaoning, 1774-1873

Fate and Fortune in Rural China: Social Organization and Population Beliavior in Liaoning, 1774-1873. James Lee and Cameron Campbell. Cambridge: Cambridge University Press, 1997. 280 pp.