Matching Items (3)
Description
My dissertation contributes to a body of knowledge useful for understanding the evolution of subsistence economies based on agriculture from those based on hunting and gathering, as well as the development of formal rules and norms of territorial ownership in hunter-gatherer societies. My research specifically combines simple formal and conceptual models with the empirical analysis of large ethnographic and environmental data sets to study feedback processes in coupled forager-resource systems. I use the formal and conceptual models of forager-resource systems as tools that aid in the development of two alternative arguments that may explain the adoption of food production and formal territorial ownership among hunter-gatherers. I call these arguments the Uncertainty Reduction Hypothesis and the Social Opportunity Hypothesis. Based on the logic of these arguments, I develop expectations for patterns of food production and formal territorial ownership documented in the ethnographic record of hunter-gatherer societies and evaluate these expectations with large ethnographic and environmental data sets. My analysis suggests that the Uncertainty Reduction Hypothesis is more consistent with the data than the Social Opportunity Hypothesis. Overall, my approach combines the intellectual frameworks of evolutionary ecology and resilience thinking. The result is a theory of subsistence change that integrates elements of three classic models of economic development with deep intellectual roots in human ecology: The Malthusian, Boserupian and Weberian models. A final take home message of my study is that evolutionary ecology and resilience thinking are complementary frameworks for archaeologists who study the transition from hunting and gathering to farming.
ContributorsFreeman, Jacob (Author) / Anderies, John M (Thesis advisor) / Nelson, Margaret C. (Thesis advisor) / Barton, C Michael (Committee member) / Arizona State University (Publisher)
Created2014
Description
This work investigates the effects of non-random sampling on our understanding of species distributions and their niches. In its most general form, bias is systematic error that can obscure interpretation of analytical results by skewing samples away from the average condition of the system they represent. Here I use species distribution modelling (SDM), virtual species, and multiscale geographically weighted regression (MGWR) to explore how sampling bias can alter our perception of broad patterns of biodiversity by distorting spatial predictions of habitat, a key characteristic in biogeographic studies. I use three separate case studies to explore: 1) How methods to account for sampling bias in species distribution modeling may alter estimates of species distributions and species-environment relationships, 2) How accounting for sampling bias in fossil data may change our understanding of paleo-distributions and interpretation of niche stability through time (i.e. niche conservation), and 3) How a novel use of MGWR can account for environmental sampling bias to reveal landscape patterns of local niche differences among proximal, but non-overlapping sister taxa. Broadly, my work shows that sampling bias present in commonly used federated global biodiversity observations is more than enough to degrade model performance of spatial predictions and niche characteristics. Measures commonly used to account for this bias can negate much loss, but only in certain conditions, and did not improve the ability to correctly identify explanatory variables or recreate species-environment relationships. Paleo-distributions calibrated on biased fossil records were improved with the use of a novel method to directly estimate the biased sampling distribution, which can be generalized to finer time slices for further paleontological studies. Finally, I show how a novel coupling of SDM and MGWR can illuminate local differences in niche separation that more closely match landscape genotypic variability in the two North American desert tortoise species than does their current taxonomic delineation.
ContributorsInman, Richard (Author) / Franklin, Janet (Thesis advisor) / Fotheringham, A. Stewart (Committee member) / Dorn, Ronald (Committee member) / Arizona State University (Publisher)
Created2018
Description
Rapidly growing research on mothers’ perinatal depression, has demonstrated significant links among mothers’ depressive symptoms during pregnancy and the first year postpartum, their parenting, and multiple aspects of children’s development. This prospective longitudinal study contributes to research on mothers’ perinatal depression by examining the mechanisms by which maternal perinatal depression is associated with children’s adjustment early in development in a sample of 204 Mexican-origin adolescent mothers (Mage at Wave 1 = 16.80, SD = 1.0) and their children (58% boys). I expected that adolescent mothers’ negative parenting behaviors would mediate the associations between mothers’ perinatal depressive symptoms and three child outcomes: internalizing symptoms, externalizing behaviors, and cognitive ability. I further hypothesized that mothers’ perceived social support from their family would modify the extent to which mothers’ perinatal depressive symptoms negatively impact their parenting behaviors and their children’s developmental outcomes. Mothers reported on their own depressive symptoms, their perceived social support from their family and their children’s internalizing and externalizing problems; negative parenting was assessed using observational methods; and children’s cognitive ability was assessed using standardized developmental assessments. In this sample, adolescent mothers’ negative parenting behaviors did not significantly mediate the relations between mothers’ perinatal depression and children’s developmental outcomes. Further, perceived social support did not significantly buffer the effects of mothers’ perinatal depression on mothers’ negative parenting or children’s developmental outcomes. However, in line with hypotheses, results indicated that mothers’ prenatal depression had a wider impact on children’s adjustment outcomes than mothers’ postpartum depression, which appeared more specific to children’s internalizing problems. Discussion focuses on implications for intervention addressing adolescent mothers’ perinatal depression, as well as the need to continue to explore protective factors that have the potential to disrupt the negative intergenerational transmission of risks.
ContributorsSeay, Danielle M (Author) / Elam, Kit (Thesis advisor) / Iida, Masumi (Thesis advisor) / Thompson, Marilyn (Committee member) / Wilkens, Natalie (Committee member) / Arizona State University (Publisher)
Created2019