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<p> A strong understanding of the role of kissing has important theoretical implications; however little research has been done on kissing in romantic relationships. This study aimed to examine the role of kissing in (a) mate assessment, (b) initiating arousal and (c) maintenance of an emotional bond. Data were collected by surveying college students at a public university in the northeast. The first survey (n = 121) examined the memory of the first kiss compared to other sexual &ldquo;firsts&rdquo; as well as the relationship between the first kiss and relationship outcome. Memories of the first kiss were weaker than memories of first sex and quality of the first kiss was not associated with relationship outcome. The second survey (n= 67) asked participants to rate their first kiss with their current partner as well as their satisfaction with various aspects of their current relationship. Quality of the first kiss was positively correlated with current relationship satisfaction, particularly sexual satisfaction in men and emotional satisfaction in women. This relationship was much weaker in women on hormonal birth control. Satisfaction with kissing in the current relationship was also positively correlated with relationship satisfaction in women, but not men. In the third study (n = 55), respondents were asked to report which type of kiss was mostly likely in a variety of contexts. They were also asked to predict how likely a &ldquo;great kisser&rdquo; was to have a variety of other attributes. The results suggest that closed mouth kissing is primarily related to emotional intimacy and conflict resolution and open mouth kissing with tongue contact is most associated with sexual arousal and attraction. Overall, the results provide strong evidence that kissing is important in romantic relationships. Additional research should be done to further elucidate the exact role that kissing plays in mate assessment, relationship maintenance and sexual attraction and how it varies by gender.</p>

<p>Understanding forces creating or maintaining the vast amount of biodiversity has been a major task of biologists. Genetic variation plays a major role in the creation of biodiversity because in contrast to environmental influence, genetic variants can be inherited. For a species in natural environments, genetic variation is generated by mutation, eliminated by genetic drift or selective sweep, and maintained by balancing selection that favors different alleles in different environments or time. In my dissertation, I will address how spatially heterogeneous environmental selection maintains genetic variation in two aspects.</p><p>Genes in the genome vary vastly in their level of polymorphism. Previous studies have used features within the genome, such as recombination rate or expression level, to explain the variation in gene polymorphism. One factor, however, that has often been overlooked is the effect of environmental adaptation on gene polymorphism. Specifically, if different alleles of a gene are responsible for local adaptation to distinct environments, the polymorphism of this gene will be actively maintained by spatially heterogeneous environmental selection. In the first part (Chapter 2) of my dissertation, I used publicly available genomic data from Arabidopsis thaliana to address this question. I found that environmental relevance of a gene has a significantly positive relationship with the variation in polymorphism level among genes in the Arabidopsis genome, consistent with the hypothesis that environmental selection actively maintains the polymorphism of environmentally responsive genes.</p><p>A biological species is formed by a mating pool of individuals, and for two populations of the same species, differentiation is often homogenized by gene flow. Reproductive isolation between populations allows genetic differentiation, and therefore speciation, the process in which full reproductive isolation is achieved between populations, plays important role in generating biodiversity. In the second part of my dissertation I used Boechera stricta to address how environmental selection contributes to speciation. In Chapter 3, I used niche modeling to show that environmental factors have more important roles than geographical distance in the genetic differentiation of EAST and WEST subspecies, and local water availability is the most important factor. In Chapter 4, I performed large-scale greenhouse experiments to identify key traits responsible for the EAST-WEST local adaptation, and that those traits have significantly larger differentiation between subspecies than neutral expectation. In Chapter 5, I performed quantitative trait loci mapping for those important traits and fitness in both parental environments and greenhouse. In summary, the second part of my dissertation provides an example to study ecological speciation from the environment, trait, to the genetic level.</p> / Dissertation

<p> One of the consequences of the development of landscapes for human uses is the release and accumulation of chemicals in the environment. The long-term effects of multigenerational exposure to this chemical pollution in wild populations are poorly understood. Both ecological and rapid evolutionary responses are likely, as both species and populations are known to vary in sensitivity to toxicant exposure. While we have observed frequent rapid evolutionary changes in wild populations, particularly in response to human impacts, we are only beginning to understand how important rapid evolution might be in shaping long-term ecological and evolutionary responses to environmental stressors such as chemical pollution. My dissertation uses freshwater zooplankton as a model to contribute to this knowledge gap, examining both ecological and evolutionary consequences of exposure to pollution stress across a variety of spatial and temporal scales. In chapter one I surveyed 51 small lakes in Connecticut, US to evaluate the relative importance of the lake physicochemical environment, habitat connectivity and broader spatial properties in shaping pelagic crustacean zooplankton communities. I found that the chemical environment, particularly dissolved ions, was far more important than space and connectivity in predicting zooplankton species distributions. This evidence suggests that for the most part in this system zooplankton dispersal is not limited and environmental filtering is playing a key role in the distribution of zooplankton species across the landscape. Chapters 2 through 4 examined long-term ecological and evolutionary changes in daphniid zooplankton taxa in four Connecticut lakes that have experienced differing degrees of pollution over the past century. Using paleolimnological techniques I reconstructed changes in eutrophication and heavy metal contamination in these lakes over time. Examination of daphniid diapausing egg banks deposited in sediments of these lakes uncovered evidence of taxonomic homogenization of the daphniid species over time in the three eutrophied lakes. I also found that eutrophication may have been more influential than metals in shaping species compositional patterns (chapter 2). Chapters 3 and 4 investigated phenotypic responses of <i>Daphnia ambigua</i> populations to heavy metal contamination. I found that <i>Daphnia</i> diapausing eggs from time periods when metal contamination was elevated were less likely to hatch and that those animals that did hatch had a higher rate of juvenile mortality (chapter 3). <i>Daphnia</i> hatched and successfully cultured from high copper and high cadmium time periods were more sensitive to exposure of these metals (chapter 4), a pattern consistent with rapid maladaptation to metals over multi-decadal timescales. Overall, my dissertation research uncovers widespread long-term effects of changes in lake chemical environments on both ecological and evolutionary trajectories of lake zooplankton communities. Future research into the drivers and consequences of these trends, particularly those observed in chapters 3 and 4, is warranted. It is important to understand, both for basic scientific and conservation purposes, whether exposure to widely distributed toxicants such as heavy metals is disrupting the evolutionary capacity of lake zooplankton, an important component to lake communities worldwide. </p>

<p> The unique nature of island ecosystems have fascinated generations of naturalists, ecologists, and evolutionary biologists. Studying island systems led to the development of keystone biological theories including: Darwin and Wallace's theories of natural selection, Carlquist's insights into the biology of adaptive radiations, MacArthur and Wilson's theory of island biogeography, and many others. Utilizing islands as natural laboratories allows us to discover the underlying fabric of ecology and evolutionary biology. This dissertation represents my attempt to contribute to this long and storied scientific history by thoroughly investigating two aspects of island biology: 1. the role of island climate in shaping drought tolerance of woody plants, and 2. the absence of mammalian herbivores from insular environments and its effects on woody plant defenses. </p><p> These goals were accomplished by quantifying functional trait patterns, seasonal water relations, and plant defenses among closely-related species pairs of chaparral shrubs from matched field sites on Santa Catalina Island and the adjacent Santa Ana Mountains in southern California. This experimental design allowed me to test for &#65532;repeated evolutionary divergences across island and mainland environments and to examine the evolutionary trade-offs between traits. </p><p> Chapter 1 focuses on differences in dry season water availability and hydraulic safety between island and mainland chaparral shrubs by measuring seasonal water relations and cavitation resistance. My results suggest that island plants are more buffered than mainland relatives from the harsh summer drought conditions that characterize the Mediterranean type climate region of California. Furthermore, island plants exhibit increased hydraulic safety margins that suggest island plants may fare better than mainland relatives during episodes of increasing aridity. </p><p> Chapter 2 examines an exhaustive suite of 12 functional traits that characterize the drought-related functional strategies of island and mainland chaparral shrubs. Island plants have more mesomorphic leaf and canopy traits than mainland relatives. However, stem hydraulic traits are surprisingly similar between the island and mainland environments despite large differences in seasonal water relations. The differences between patterns at the leaf and stem levels may be related to the existence of evolutionary correlations for leaf traits but not for stem traits. Multivariate principal component analyses suggest that island plants are employing a very different suite of functional traits than their mainland relatives that allows them to take advantage of the more moderate conditions that characterize the island environment without sacrificing increased vulnerability to drought at the stem level. </p><p> Chapter 3 tests the hypothesis that the absence of mammalian herbivores throughout most of Santa Catalina Island's history has selected for plants that are less defended and more palatable than mainland relatives that have experienced more consistent browsing pressure. My results confirm that island plants have fewer morphological defenses and are more preferred by mammalian herbivores compared to close relatives from the mainland. These findings also suggest that island plants are more vulnerable to browsing by introduced mammalian herbivores. This vulnerability should be taken into account when making management decisions concerning introduced herbivores on islands. </p><p> In conclusion, chaparral shrubs on Santa Catalina Island have different levels of drought tolerance and herbivore defenses compared to mainland relatives that affect how they are likely to be impacted by climate change and other anthropogenic alterations of the insular environment. Furthermore, the pattern of evolutionary divergences between island and mainland plants reported in this dissertation offer new insights into how drought tolerance and herbivore defenses are shaped by environmental factors. </p>

<p> Since at least the time of Darwin biologists have searched for a simple set of universal governing mechanisms that dictate the dynamics of biodiversity. While much progress has been made in understanding system-specific processes and in documenting the context-dependent roles of such mechanisms as competition and facilitation, we still lack a universal governing rule set. The goal of understanding and predicting biodiversity dynamics comes at a critical moment when human systems are disrupting those very dynamics. In this thesis I approach this long-standing problem with the hypothesis that general patterns in biodiversity emerge from a combination of the statistical mechanics of large systems and the unique non-equilibrium dynamics imparted to biological systems by their evolutionary history. Statistical mechanics provides the key analytical approaches to abstracting the complex details of biodiversity into general macroscopic predictions that I show receive support from empirical data. However, key deviations from the simplest statistical mechanics of biodiversity reveal the key role of biological evolution in driving systems away from the idealized steady state predicted by statistical mechanics. </p><p> In Chapter 1 I expand a branch of non-equilibrial statistical mechanics, known as super statistics, to explain previously unaccounted for wild fluctuations in the richness of taxa through the Phanerozoic marine invertebrate fossil record and show how this non-equilibrium is driven by clades' punctuated exploration of their adaptive landscapes. This theory provides a novel explanation for deep time diversity dynamics invoking emergence of lineage-level traits as the drivers of complexity via the same mechanisms by which complexity emerges in large physical and social systems. In the context of fossil diversity I show how this complexity arises naturally from the uniquely biological mechanisms of punctuated adaptive radiation followed by long durations of niche conservatism, and thus identify these mechanisms as sufficient and necessary to produce observed patterns in the fossil record. I test this theory using two seminal fossil datasets. </p><p> In Chapter 2 I use the chronosequence afforded by the Hawaiian Islands to capture evolutionary snapshots of arthropod communities at different ages and stages of assembly to understand how the history underlying an assemblage determine its contemporary biodiversity patterns. I apply static ecological theory of trophic networks based on statistical mechanics to these rapidly evolving ecosystems to highlight what about the evolutionary process drives communities away from statistical idealizations. This study indicates that rapid assembly from immigration and speciation in young ecosystems and extinction in old ecosystems could drive observed patterns. </p><p> In Chapter 3 I highlight and explain the computational requirements to testing one statistical theory of biodiversity&mdash;the Maximum Entropy Theory of Ecology&mdash;with real data and make those test available in a stream-lined framework via the R package meteR that I authored.</p>

<p> Adaptive phenotypic plasticity is a key mechanism by which organisms deal with variation in many different aspects of their environment. Adaptive plasticity can occur in any trait, from aspects of biochemistry and morphology to behaviors. Because so many different traits can be plastic, organisms often respond plastically to a given change in their environment, such as an increase in temperature, with adaptive changes in multiple traits. Nevertheless, how these different plastic responses interact with each other and evolve together has received little attention. My research addresses these potential interactions among plastic traits and proposes new hypotheses regarding the causes and consequences of these interactions. It does so by focusing on heat avoidance in the caterpillars of <i>Battus philenor</i> (the pipevine swallowtail) which involves two distinct plastic mechanisms. First, the caterpillars can change color when they molt, a form of morphological plasticity in which they develop a red color under high temperatures which cools them by absorbing less solar radiation. Second, when the caterpillars become too hot, they will leave their host to seek cooler thermal refuges, a case of behavior as a form of plasticity. In terms of function, I demonstrated through field research that these two responses to high temperatures are largely redundant. Behavior provides a much stronger and faster response than color change, and red coloration provides little additional cooling when on a refuge. Instead, the primary benefit of color change is that it reduces the use of refuge seeking behavior, allowing the caterpillars to stay on their hosts longer. Using laboratory experiments, I demonstrated that this change in the use of refuge-seeking behavior with color occurs because color changes the cue for the behavior, body temperature, rather having any effect on how the caterpillar responds to that cue. Alternatively, similar experiments on caterpillars of varying sizes show that developmental size change lowers the body temperature at which caterpillars leave their host, demonstrating a change in the response to the cue (although larger caterpillars are also warmer, so both mechanisms are likely relevant for how size changes the expression of behavior). All of my research to this point was conducted on the local population in southern Arizona, which experiences quite high temperatures, but <i>B. philenor</i> is also found in much cooler environments, such as the Appalachian Mountains. Given this variation in their thermal environment, I used common garden experiments to compare the capacity for color change and refuge-seeking among B. philenor caterpillars from across the species range. Both color change and refuge seeking not only occurred in all populations, but also had the same reaction norms, occurring at the same temperatures and to the same degree. This is particularly notable for color change, which is not observed in the wild in northeastern populations, and thus has persisted despite minimal if any use. Overall, I have shown that studies of plasticity need to account for plasticity in different traits as well as the interactions between these forms of plasticity. My research on B. philenor provides a model for how to address these interactions, which future research can extend to additional organisms and environmental circumstances. </p>

<p> Child maltreatment models view risk as a complex constellation of factors that emphasize parents&rsquo; trauma experiences and regulation processes. Attachment research has shown that mothers&rsquo; representations of childhood attachment and caregiving places their children at developmental risk. Studies to date have evaluated contributing factors separately, but little research considers mothers&rsquo; past and current experiences combined with relational trauma and familial regulation patterns. The current research adopted an integrated perspective using known maternal risk factors, and extended existing research in several unique ways by examining association with both adult trauma and childhood trauma; caregiving representations; pathological mourning; and capacity for emotion regulation. Seventy-five mothers with children between 19-74 months (40% boys) from diverse socio-economic and cultural backgrounds completed assessments of maltreatment risk, adult attachment, caregiving, relational trauma, parenting stress, and emotion regulation. Maternal representations of attachment were significantly related to risk, with unresolved mothers demonstrating the highest risk. There were significant positive associations between risk and relational trauma &ndash; both frequency and subjective distress with parents and partners. Helpless and heightened caregiving representations, parenting stress, and emotion regulation were also all significantly related to risk. This is the first study to consider maltreatment in the context of relational trauma as defined by Bowlby&rsquo;s (1980) model of pathological mourning. Risk scores were significantly greater for mothers classified in pathological mourning groups than other mothers. These findings punctuate the effects of problems associated with mourning attachment trauma on maternal regulatory capacities and parenting risk. Implications for infant mental health research and intervention are discussed.</p>

<p> The study of contemporary evolution and eco-evolutionary dynamics is classically defined in terms of genetic evolution, but the actual suite of processes driving contemporary trait change is likely much more complex than often credited. This dissertation considers additional mechanisms of trait change that might be important to an emerging model system for study of contemporary evolution and eco-evolutionary dynamics. Specifically, the research focuses on phenotypically plastic and demographic trait variation in Eastern and Western Mosquitofish (<i>Gambusia affinis</i> and <i>G. holbrooki</i>) facing the major ecological gradient of predation risk. Plasticity experiments employed a common-garden rearing design to manipulate fish predator cues experienced by individuals, their parents, or their grandparents and in turn quantify reaction norms in mosquitofish size, shape, and behavior. The two species of mosquitofish showed divergent plastic responses in behavior, with the relatively bolder <i>G. holbrooki</i> becoming even bolder in response to predator cues. In contrast, males and females within species showed parallel behavioral responses. Despite strong sexual dimorphism, both sexes and both species showed parallel patterns of plasticity toward streamlining of body shape when exposed to predators. Interestingly, mosquitofish also showed evidence of transmitting predator cues across generations, where female <i>G. affinis</i> become shyer and more streamlined when their parents or grandparents experienced predators. In contrast, male <i>G. affinis</i> showed little evidence of transgenerational plasticity and appear to rely more heavily on their own experience. Another set of field surveys and experiments with <i>G. hoibrooki </i> considered the potential role of sexual dimorphism and demographic variation in sex ratios as another form of trait variation with possible community and ecosystem consequences. Natural population surveys revealed female-biased sex ratios and higher primary production in the absence of predators. Mesocosm experiments suggested males and females differed in dietary preferences and that both sex ratio and density influence community responses. Although these findings support a need to expand the current eco-evolutionary synthesis to mechanisms beyond just genetic evolution, they also support some general patterns in these mechanisms and ways in which they might work with evolution to produce an even more dynamic interaction of ecology and trait change in nature.</p>

<p>Population differentiation is both one of the central processes underlying the diversity that we observe in the natural world, and a mechanism that can be used to differentiate between evolutionary forces both at the level of the polymorphism, and at the level of the entire genome. Here, I use simulated evolution to analyze the statistical power to detect signals of selection in artificially selected laboratory populations, and use genomic data from wild populations of the clam shrimp Eulimnadia texana to identify genomic signals of selection in wild populations. Several loci in the wild populations appear to be under selection, and I analyze the types of genes that appear to contribute to differentiation of these populations. Additionally, I describe an analysis of genome assembly techniques that allowed for the creation of a highly contiguous genome assembly in the clam shrimp. I find that a pipeline that uses custom software to combine the results of several different genome assemblers is capable of producing genomes using long-read genomic sequencing data that are orders of magnitude more contiguous that pre-long-read methods. Simulations of experimental evolution indicated that extremely high levels of replication were necessary in order to achieve high power to detect signals of selection in experimental evolution. To this end, I describe a set of replicate experimentally evolved populations of E. texana that can be used to identify regions under selection with much higher power than could be accomplished with earlier experimental evolution schemes.