<p>The pace of life history is highly variable across mammals, and several evolutionary biologists have theorized that the tempo of a species' life history is set by external factors. These factors, such as food availability and predation pressure, determine mortality rates. In turn, mortality rate determines the age at maturity. High mortality rate results in early age at maturity; individuals must grow and reproduce quickly because of the high risk of death. Conversely, a low mortality rate is allows individuals to prolong their growth period and reproduce slowly. This theory assumes that growth rates are constant across species, and thus body size is determined by mortality rates.</p><p>This project posits that the intrinsic characteristics of species set the pace of life history. Among anthropoids, there is a great deal of variation in growth rates and the pace of life history relative to body size. The hypotheses proposed by this project state that the degree of encephalization in a species determines the growth rates, the length of the growth period, and the adult lifespan. Growing a large brain is costly and requires a prolonged period of development. However, a large brain has the benefit of reducing mortality by facilitating cognitive strategies for food procurement and predator avoidance. This cost/benefit balance results in the pattern of life-history variation in which mortality rates are correlated with the length of the growth period. However, the causal arrows are reversed; instead of the mortality rate determining the age at maturity and consequently the size of the species, the relative brain size of the anthropoid determines the mortality rate and the age maturity.</p><p>These hypotheses were tested by determining the body and brain growth trajectories of thirteen anthropoids, and compiling life-history data from long-term studies of these species in the wild. Multi-variate analyses demonstrated that extensive brain growth, whether through prolonged duration or rapid growth rates, results in slow body-growth rates during the juvenile period and delayed age at maturity. In addition, encephalization results in longer adult lifespan. Therefore, this project demonstrated that intrinsic characteristics of anthropoid species determine the pace of their life histories.</p> / Dissertation

<p>Although evolution results from differential reproduction and survival at the level of the individual, most research in evolutionary genetics is concerned with comparisons made at the level of divergent populations or species. This is particularly true in work focused on the evolutionary genetics of natural populations. While this level of inquiry is extremely valuable, in order to develop a complete understanding of the evolutionary process we also need to understand how traits evolve within populations, on the level of differences between individuals, and in the context of natural ecological and environmental variation. A major difficulty confronting such work stems from the difficulty of assessing interindividual phenotypic variation and its sources within natural populations. This level of inquiry is, however, the main focus for many long-term field studies. Here, I take advantage of one such field study, centered on the wild baboon population of the Amboseli basin, Kenya, to investigate the possibilities for integrating functional, population, and evolutionary genetic approaches with behavioral, ecological, and environmental data. First, I describe patterns of hybridization and admixture in the Amboseli population, a potentially important component of population structure. Second, I combine field sampling, laboratory measurements of gene expression, and a computational approach to examine the possibility of using allele-specific gene expression as a tool to study functional regulatory variation in natural populations. Finally, I outline an example of how these and other methods can be used to understand the relationship between genetic variation and naturally occurring infection by a malaria-like parasite, Hepatocystis, also in the Amboseli baboons. The results of this work emphasize that developing genetic approaches for nonmodel genetic systems is becoming increasingly feasible, thus opening the door to pursuing such studies in behavioral and ecological model systems that provide a broader framework for genetic results. Integrating behavioral, ecological, and genetic perspectives will allow us to better appreciate the interplay between these different factors, and thus achieve a better understanding of the raw material upon which selection acts.</p> / Dissertation

<p> Puerto Rico has the highest prevalence of type 2 diabetes, low birth-weight, and the second highest prevalence of preterm-birth in all the U.S. and its non-incorporated territories. These conditions are related. Birth-weight at both ends of the spectrum and preterm-birth are associated with an increased risk for developing type 2 diabetes and immune-inflammatory dysregulations. Maternal psychosocial stressors during pregnancy have also been recognized as potential risk factors for type 2 diabetes, and have been consistently associated with preterm-birth and low birth-weight across populations. Current evidence points toward epigenetic fetal metabolic-programming as the mechanism that underlies the increased risk for the previously mentioned morbidities. However, the particular psychosocial stressors that may contribute to the high prevalence of low birth-weight and preterm-birth in the population of Puerto Rico have not been well studied.</p><p> The present study assesses the relationships between particular psychosocial stressors, socioeconomic status, food insecurity, and birth outcomes. The results of this study show that low-risk pregnancy women were more likely to have babies with a higher ponderal index if they were exposed to stressors during gestation months 5, 6, and 7, or if exposed to "relationship stress" at any time during pregnancy. Women exposed to "financial difficulties" at any time during pregnancy were more likely to deliver babies at an earlier gestational age. Differences in birth outcomes between the exposed and non-exposed women were independent of maternal anthropometric measurements, maternal age at birth, number of previous births, and sex of the baby. Significant differences in birth outcomes were found between categories of father's self-identified and identified by others ethnicity, but sample size within categories was small. Although mothers with children at home had higher levels of food insecurity, and the level of food insecurity was correlated with higher levels of stress, no birth outcome measure was associated with food insecurity.</p><p> Some results are atypical in comparison with other populations, and therefore these findings may contribute to the understanding of population differences in the relationship between maternal stress during pregnancy and birth outcomes. The relatively small sample size and strict exclusion criteria of this study may limit the generalizability of the findings. Epidemiological similarities between Puerto Rico and other populations, and the possibility of a higher ponderal index increasing the risk for type 2 diabetes in the population of Puerto Rico need to be examined in future research.</p>

Le rire est un comportement humain indiscutablement universel. Abondamment traité par la psychologie et les neurosciences, il demeure néanmoins le laissé-pour-compte de l’anthropologie. Si les connaissances empiriques accumulées à ce jour ont permis de bien le caractériser à des niveaux proximaux d’analyse, la question de son origine évolutionniste est, en contrepartie, souvent évacuée. Or, toute tentative sérieuse de comprendre ce comportement requiert une investigation de sa fonction adaptative et de sa phylogénèse. Le projet entrepris ici consiste en une analyse de cinq hypothèses ultimes sur le rire et l’humour, desquelles sont extraites des prédictions qui sont confrontées à des données empiriques provenant de disciplines diverses. En guise de conclusion, il est tenté de formuler un scénario évolutif qui concilie les différentes hypothèses abordées. / Laughter is a universal and ubiquitous human behavior. Widely investigated by psychology and neuroscience, it is still largely ignored by anthropology. While humor and laughter are well caracterised at proximate levels of explanation, the question of their evolutionary origins remains relatively unexplored. A number of recent hypotheses have yet attempted to shed light on the potential adaptive significance and phylogeny of these behaviors. This project consists of an analysis of five of these ultimate explanations, by confronting their predictions to empirical data from a large array of disciplines. In the end, I propose an evolutionary framework that synthesizes and reconciles these hypotheses.

This work follows the direction set by Sewall Wright in applying path analysis, and other multivariate statistical techniques, to the study of anthropometric variation. Data on anthropometric variation of six Solomon Island populations is analyzed using statistical models which can distinguish between within-group and between-group genetic variation. The correlation structure of 27 anthropometric measurements is examined by cluster analysis and principal components analysis. The six populations show a common pattern (in both males and females) which echoes earlier studies. The correlation matrix of measurements is then partitioned into genetic and environmental components and the genetic correlation matrix is examined, once again by cluster analysis and principal components analysis. There is a fairly close agreement between the genetic correlation structure and the phenotypic correlation structure. The environmental correlation matrix is not examined further because it is very poorly estimated. The partitioning of phenotypic correlations into genetic and environmental components is based on a multivariate generalization of a path model for the heritability of a continuous trait proposed by C. C. Li. The parameters estimated in the single trait model include additive genetic heritability, common home environment, and genetic correlation between spouses. In order to fit this model observations are required on parent-offspring, spouse-spouse, and sib-sib correlations. Heritability values for the Solomons are markedly lower than those reported elsewhere. However, when total heritability (ignoring subpopulation structure) is estimated for the six Solomons populations, the values are higher and form a more familiar pattern. The striking differences between the two kinds of heritability in the Solomon Islands emphasizes the danger of using total heritability estimates obtained from several subpopulations or a national sample. The between-group component of heritability for each measurement is compared to the within-group heritability and to levels of between-group phenotypic variation. The results demonstrate that high within-group heritability for a given trait does not imply that between-group variation in that trait is genetic in origin.

This work follows the direction set by Sewall Wright in applying path analysis, and other multivariate statistical techniques, to the study of anthropometric variation. Data on anthropometric variation of six Solomon Island populations is analyzed using statistical models which can distinguish between within-group and between-group genetic variation. The correlation structure of 27 anthropometric measurements is examined by cluster analysis and principal components analysis. The six populations show a common pattern (in both males and females) which echoes earlier studies. The correlation matrix of measurements is then partitioned into genetic and environmental components and the genetic correlation matrix is examined, once again by cluster analysis and principal components analysis. There is a fairly close agreement between the genetic correlation structure and the phenotypic correlation structure. The environmental correlation matrix is not examined further because it is very poorly estimated. The partitioning of phenotypic correlations into genetic and environmental components is based on a multivariate generalization of a path model for the heritability of a continuous trait proposed by C. C. Li. The parameters estimated in the single trait model include additive genetic heritability, common home environment, and genetic correlation between spouses. In order to fit this model observations are required on parent-offspring, spouse-spouse, and sib-sib correlations. Heritability values for the Solomons are markedly lower than those reported elsewhere. However, when total heritability (ignoring subpopulation structure) is estimated for the six Solomons populations, the values are higher and form a more familiar pattern. The striking differences between the two kinds of heritability in the Solomon Islands emphasizes the danger of using total heritability estimates obtained from several subpopulations or a national sample. The between-group component of heritability for each measurement is compared to the within-group heritability and to levels of between-group phenotypic variation. The results demonstrate that high within-group heritability for a given trait does not imply that between-group variation in that trait is genetic in origin.

This work follows the direction set by Sewall Wright in applying path analysis, and other multivariate statistical techniques, to the study of anthropometric variation. Data on anthropometric variation of six Solomon Island populations is analyzed using statistical models which can distinguish between within-group and between-group genetic variation. The correlation structure of 27 anthropometric measurements is examined by cluster analysis and principal components analysis. The six populations show a common pattern (in both males and females) which echoes earlier studies. The correlation matrix of measurements is then partitioned into genetic and environmental components and the genetic correlation matrix is examined, once again by cluster analysis and principal components analysis. There is a fairly close agreement between the genetic correlation structure and the phenotypic correlation structure. The environmental correlation matrix is not examined further because it is very poorly estimated. The partitioning of phenotypic correlations into genetic and environmental components is based on a multivariate generalization of a path model for the heritability of a continuous trait proposed by C. C. Li. The parameters estimated in the single trait model include additive genetic heritability, common home environment, and genetic correlation between spouses. In order to fit this model observations are required on parent-offspring, spouse-spouse, and sib-sib correlations. Heritability values for the Solomons are markedly lower than those reported elsewhere. However, when total heritability (ignoring subpopulation structure) is estimated for the six Solomons populations, the values are higher and form a more familiar pattern. The striking differences between the two kinds of heritability in the Solomon Islands emphasizes the danger of using total heritability estimates obtained from several subpopulations or a national sample. The between-group component of heritability for each measurement is compared to the within-group heritability and to levels of between-group phenotypic variation. The results demonstrate that high within-group heritability for a given trait does not imply that between-group variation in that trait is genetic in origin.

This work follows the direction set by Sewall Wright in applying path analysis, and other multivariate statistical techniques, to the study of anthropometric variation. Data on anthropometric variation of six Solomon Island populations is analyzed using statistical models which can distinguish between within-group and between-group genetic variation. The correlation structure of 27 anthropometric measurements is examined by cluster analysis and principal components analysis. The six populations show a common pattern (in both males and females) which echoes earlier studies. The correlation matrix of measurements is then partitioned into genetic and environmental components and the genetic correlation matrix is examined, once again by cluster analysis and principal components analysis. There is a fairly close agreement between the genetic correlation structure and the phenotypic correlation structure. The environmental correlation matrix is not examined further because it is very poorly estimated. The partitioning of phenotypic correlations into genetic and environmental components is based on a multivariate generalization of a path model for the heritability of a continuous trait proposed by C. C. Li. The parameters estimated in the single trait model include additive genetic heritability, common home environment, and genetic correlation between spouses. In order to fit this model observations are required on parent-offspring, spouse-spouse, and sib-sib correlations. Heritability values for the Solomons are markedly lower than those reported elsewhere. However, when total heritability (ignoring subpopulation structure) is estimated for the six Solomons populations, the values are higher and form a more familiar pattern. The striking differences between the two kinds of heritability in the Solomon Islands emphasizes the danger of using total heritability estimates obtained from several subpopulations or a national sample. The between-group component of heritability for each measurement is compared to the within-group heritability and to levels of between-group phenotypic variation. The results demonstrate that high within-group heritability for a given trait does not imply that between-group variation in that trait is genetic in origin.

Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2007. / Source: Dissertation Abstracts International, Volume: 68-06, Section: A, page: 2529. Adviser: R. Barry Lewis. Includes bibliographical references (leaves 186-215) Available on microfilm from Pro Quest Information and Learning.

Thesis (Ph.D.)--McMaster University, 2006. / Supervisor: Shelley R. Saunders. Includes bibliographical references (leaves 285-322).