Continuing evolution of man, session IV.
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Anthropology↗
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The biosocial female choice theory of social stratification.
For decades, the study of social stratification has been dominated by environmental theories. Herein a theory is proposed that contains both biological and sociocultural elements. The theory asserts that most human females, like females of many other mammalian species, have evolved mating preferences biased toward males who are competent in provisioning resources. This female bias is hypothesized to have been naturally selected because females with these biases nearly always have had a reproductive edge over females who lack such a bias. One result of this bias is that human females preferentially mate with males who strive to rise in social status. This, in turn, has favored males who attain or at least strive for high social status, and who advertise and even exaggerate whatever status they already have achieved. At the genetic level, the theory postulates that alleles have accumulated on the human genome that promote social status-striving and achievement to varying degrees. To account for why males are more prone toward status-striving than females, the theory contends that one or more genes on the Y-chromosome interact with genes on the remaining human chromosomes to incline males to gravitate toward social hierarchies and to strive for niches that are relatively high in those hierarchies. Both tested and untested hypotheses are derived from the theory and compared to the empirical evidence currently available.
Cultural Evolution↗
Sociobiology: science in the service of ideology.
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Biology↗
Evolution of anaerobe susceptibility testing in the United States.
Susceptibility testing of anaerobes has been described for approximately 45 years, some 15 years fewer than descriptions for aerobic organisms. During that time period, >16 methods, >16 media, and a host of other variables have been described in the United States literature, culminating in the most recent standards published by the National Committee for Clinical Laboratory Standards (NCCLS) in 2001. These new guidelines include a single agar dilution reference method as well as an alternative minimal inhibitory concentration method validated by extensive multilaboratory collaborative trials. In addition, the Food and Drug Administration-approved E-test has proved valuable as a user-friendly alternative to NCCLS methods. Highlights of the "evolution" of various methods, their variations and their failures, factors that affected the development of the current standards, and the rationale for susceptibility testing of anaerobes are discussed herein.
Bacteria, Anaerobic↗
The structures of letters and symbols throughout human history are selected to match those found in objects in natural scenes.
Are there empirical regularities in the shapes of letters and other human visual signs, and if so, what are the selection pressures underlying these regularities? To examine this, we determined a wide variety of topologically distinct contour configurations and examined the relative frequency of these configuration types across writing systems, Chinese writing, and nonlinguistic symbols. Our first result is that these three classes of human visual sign possess a similar signature in their configuration distribution, suggesting that there are underlying principles governing the shapes of human visual signs. Second, we provide evidence that the shapes of visual signs are selected to be easily seen at the expense of the motor system. Finally, we provide evidence to support an ecological hypothesis that visual signs have been culturally selected to match the kinds of conglomeration of contours found in natural scenes because that is what we have evolved to be good at visually processing.
Cultural Evolution↗
Healthy places, healthy spaces.
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Cultural Evolution↗
Social capital and health.
Social capital refers to bonds between individuals, both in intimate relationships (primary groups) and in voluntary associations (secondary groups) that make it possible for individuals and groups to achieve a variety of goals. Such bonds have also been claimed to have health promoting effects. In this chapter, I review a variety of empirical studies at both levels of analysis and suggest that the results are mixed, much depending upon the context in which such relationships occur.
Caregivers↗
The social origins and expressions of illness.
This chapter draws on British medical anthropologist Ronald Frankenburg's notion of the 'making social of disease', and his related concepts 'the making of disease' and 'the making individual of disease', to review the biomedical conception of disease from the perspective of medical anthropology. As opposed to the tendency of biomedicine to treat disease as a category in nature, a finite and objective reality discoverable through scientific endeavour, medical anthropology seeks to demonstrate the social origins of both the biomedical conception of disease and the expression of the sicknesses labelled diseases by doctors.
Anthropology, Cultural↗
Culture and the risk of disease.
Decades of research have demonstrated that disease risk varies in relation to culture. Much of this research has focused on blood pressure, given its relative ease of measurement under difficult field conditions. Community average blood pressures in more developed, industrialized societies are higher than those in less developed, traditional societies. These differences can be accounted for only in part by differences in body composition and nutrient intake. A portion of the difference is accounted for by more direct effects of culture on individual behaviour and physiology. This chapter reviews this evidence. Approaches to this research have included studies of communities differing in exposure to modernizing influences; studies of sociocultural stresses generated within the process of social change and modernization; and, studies of how individual differences in the ability to act on shared cultural models (referred to as 'cultural consonance') are associated with disease risk. Clinical implications of these results are briefly discussed.
Attitude to Health↗
Adaptive evolution that requires multiple spontaneous mutations. I. Mutations involving an insertion sequence.
Escherichia coli K12 strain chi 342LD requires two mutations in the bgl (beta-glucosidase) operon, bglR0----bglR+ and excision of IS103 from within bglF, in order to utilize salicin. In growing cells the two mutations occur at rates of 4 x 10(-8) per cell division and less than 2 x 10(-12) per cell division, respectively. In 2-3-week-old colonies on MacConkey salicin plates the double mutants occur at frequencies of 10(-8) per cell, yet the rate of an unselected mutation, resistance to valine, is unaffected. The two mutations occur sequentially. Colonies that are 8-12 days old contain from 1% to about 10% IS103 excision mutants, from which the Sal+ secondary bglR0----bglR+ mutants arise. It is shown that the excision mutants are not advantageous within colonies; thus, they must result from a burst of independent excisions late in the life of the colony. Excision of IS103 occurs only on medium containing salicin, despite the fact that the excision itself confers no detectable selective advantage and serves only to create the potential for a secondary selectively advantageous mutation.
Adaptation, Physiological↗
Long-term experimental evolution in Escherichia coli. VI. Environmental constraints on adaptation and divergence.
The effect of environment on adaptation and divergence was examined in two sets of populations of Escherichia coli selected for 1000 generations in either maltose-or glucose-limited media. Twelve replicate populations selected in maltose-limited medium improved in fitness in the selected environment, by an average of 22.5%. Statistically significant among-population genetic variation for fitness was observed during the course of the propagation, but this variation was small relative to the fitness improvement. Mean fitness in a novel nutrient environment, glucose-limited medium, improved to the same extent as in the selected environment, with no statistically significant among-population genetic variation. In contrast, 12 replicate populations previously selected for 1000 generations in glucose-limited medium showed no improvement, as a group, in fitness in maltose-limited medium and substantial genetic variation. This asymmetric pattern of correlated responses suggests that small changes in the environment can have profound effects on adaptation and divergence.
Adaptation, Physiological↗
The status of the aged in Korea: are the modern more advantaged?
Using individual modernity as a measure of modernization and decision-making power to assess the status of the aged at the micro level, this study examines how modernity, family environment, and demographic characteristics affect the status of the aged in the extended family. Data are analyzed from a sample of 252 Korean elderly living with one of their married children. In contrast to findings at the societal level, this research indicates that individual modernity is associated with higher status of the aged. Individual modernity may become an important resource in negotiating for decision-making power with adult children.
Aged↗
Hunter-gatherer human nature and health system safety: an evolutionary cleft stick?
The stunning archaeological find of a new species of human dubbed the hobbit, formally named Homo floresiensis, is a reminder that humans and hobbits are evolved for transient lives, subsisting in an environment radically different from that of contemporary societies. Although the problems facing health systems are well documented, few scholars have taken an evolutionary-level approach to understanding them. By considering the nature of humans as adapted not for modern societies but for hunter-gatherer existence, and examining what humans were evolved for, new light can be shed on contemporary behaviours exposed by the medical inquiries into what is going wrong in acute health systems. Investigation of two of these inquiries shows how health professionals under pressure typically default to tribal behaviours, have recourse to hierarchies and engage in turf protection routines. Those who have conducted studies into iatrogenic harm or presided over the medical inquiries have argued that culture change is the solution to health care's ills. This is likely to be much harder to institute than some people realize, especially given our underlying hunter-gatherer nature. This is an evolutionary cleft stick that has not been factored in by those optimistic about health sector reform. The implications are that we need a deep understanding of human nature in addressing health system problems and to recognize that profound culture change is more challenging than many believe. Paradoxically, it is when humans are faced with seemingly intractable problems that a collective way forward might emerge.
Cooperative Behavior↗
Far East's cancer mortality patterns shift, reflecting cultural changes.
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Air Pollution, Indoor↗
Infant-parent co-sleeping in an evolutionary perspective: implications for understanding infant sleep development and the sudden infant death syndrome.
Evidence suggests that infant-parent co-sleeping represents the species-wide pattern of sleep in which human infant physiology evolved. The hypothesis evaluated in this manuscript is that the co-sleeping environment may foster development of optimal sleep patterning in infants and confer other benefits, including reducing the risk of the sudden infant death syndrome (SIDS). These postulations by McKenna are considered from different perspectives by the coauthors. Using evolutionary, cross-species, crosscultural, physiological and behavioral data, our objective was to present a conceptual framework for assessing the developmental consequences of solitary sleeping and infant-parent co-sleeping.
Adult↗
FASEB opposes using science classes to teach intelligent design, creationism, and other non-scientific beliefs.
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Biological Evolution↗