Dogs (Canis lupus familiaris) and wolves (Canis lupus lupus) share genotypes, which are nearly identical, but their behavioral phenotypes are very different. It has been repeatedly hypothesized that these adult behavioral differences are the result of heterochronic changes, or differences during the course of development. This dissertation investigates three major behavioral differences between these two morphs: (1) Interspecies socialization: both dogs and wolves are capable of forming interspecies attachments, most commonly with humans, but wolves require more intense exposure to reach a less intense attachment. (2) Expression of species-typical motor patterns: while dogs and wolves have the same species-typical motor patterns, they express them at different rates and in different frequencies. (3) Frequency of barking: while both dogs and wolves bark, dogs bark at a much higher frequency than wolves. The primary objective of this dissertation is to determine if behavioral differences between polymorphs of the genus Canis are the result of heterochrony. Fifty-two Canis pups including, both mother- and hand-reared dogs (Canis lupus familiaris) represented by two breeds (Border collies and German shepherds) and hand-reared wolves were observed. Frequency of motor pattern display was recorded from two to eight weeks of age in all groups. Responses of pups to olfactory, auditory, and visual stimuli were also tested weekly from two to seven weeks of age. Groups were then compared on the timing of the onset and frequency of expression of foraging motor patterns (orient, eye, stalk, chase, and grab-bite) and the onset of their ability to orient towards olfactory, auditory, and visual stimuli. My results demonstrate that small changes in the timing of the critical period of socialization in relationship to the development of the sensory systems do account for differences in the ability to form interspecies social attachments between dogs and wolves. The data also demonstrate that there are heterochronic differences in the development of species typical foraging motor patterns between dogs and wolves. However, these changes alone do not explain the fragmenting of breed-typical sequences in relation to functional wolf sequences. Investigation of barking frequency was accomplished by searching previous literature to define acoustic measurements, which distinguish the bark from other vocalizations. This definition was then used to determine in what situations the bark occurred in dogs, wild Canis species, other mammals, and birds. Barking occurs in a large variety of mammals and birds, and is motivated by conflicting internal states associated with mobbing. This is supported by the acoustic structure of the bark itself and the contexts in which mammals, including dogs and other members of the genus Canis, and birds use the bark vocalization.

No description available.

<p> Adaptive radiations offer unique insight into how diversification is initiated in novel or changing environments but the value of such studies is often limited by incomplete or lacking information on the ancestral species. The threespine stickleback species complex is proving to be particularly valuable in enhancing our understanding of evolutionary processes because there is reason to believe a surrogate for the ancestral group is extant and representative of the oceanic form that gave rise to most post-glacial freshwater populations during the last ~12,000 years. If we are to maximize the value of this radiation a thorough understanding of the putative ancestor group is needed. This dissertation explores the degree of phenotypic variation in oceanic stickleback in Cook Inlet, AK as well as the relative contributions of genetic and plastic aspects shaping the phenotypic variation revealed.</p><p> Geometric morphometrics were used to describe shape differences in two oceanic forms of stickleback, anadromous and fully marine. These groups differ in shape along the same benthic-limnetic axis described within the freshwater derived populations in the same region. A common-garden rearing study revealed high levels of body shape plasticity in both groups as well as likely genetic influences maintaining important aspects of shape differences between their stocks of origin. Interestingly, plasticity related to the salinity of early rearing environment differed across types suggesting that there may be a flexible dual stem in the threespine stickleback radiation, a surprising result that has not been considered to date in any system to my knowledge.</p><p> Additionally, because life-history traits are intimately linked to reproductive success and thus fitness, differences in life-history strategies between these two oceanic types should reflect meaningful adaptive variation, whether plastic or strictly genetic based. Established methodologies in stickleback life-history studies were employed to assess phenotypic variation across populations, types, and years in many important traits (e.g., egg and clutch size, reproductive effort, allometric relationships between reproductive effort and female body size). Life-history strategies differed significantly across type and year. Generally, marine females exhibit greater reproductive investment and have larger and more numerous eggs per clutch. Anadromous populations experience an apparent reproductive cost to the migration to freshwater relative to their fully-marine counterpart. It&rsquo;s unclear from these studies then where the fitness advantage to anadromy lies in the primitively oceanic species complex. However, important differences in mortality on the breeding grounds for adults and young as well as a possibly faster clutch production frequency in the anadromous lifestyle explains the apparent paradox in these data.</p><p> The finding of differences in genetic and plastic contributions to oceanic stickleback phenotypes body shape and life histories across two types in close geographic proximity which correlates with salinity regime suggest a flexible dual stem in the oceanic group(s). This could then influence evolution within the freshwater radiation. Thus, depending upon the freshwater populations (or watersheds) studied, the choice of representative oceanic type would need to be carefully considered. These data suggest that any near shore or inland sea areas within the stickleback oceanic distribution which experience a wide range of salinities is likely to show associated clinal variation in stickleback population reaction norms for (at least) body shape, life history strategies, and likely many other traits which are sensitive to salinity, such as genes involved in osmoregulation. Recent studies of Baltic and Sea of Japan oceanic stickleback further support this conclusion.</p>

<p> Grandparental investment in grandchildren is a topic of interest within the field of evolutionary psychology. Studies have shown a consistent pattern of differences when it comes to each grandparent&rsquo;s investment levels (Danielsbacka, Tanskanen, Jokela, &amp; Rotkirch, 2011; DeKay, 1995; Laham, Gonsakorale, &amp; Von Hippel, 2005; Michaski &amp; Shackelford, 2005; Pollet, Nettle, &amp; Nelisson, 2006). The pattern is as follows: the maternal grandmother invests the most, followed by the maternal grandfather, the paternal grandmother, and finally the paternal grandfather. The current hypotheses and theories behind this pattern are based on previous evolutionary theories of relatedness (Hamilton, 1964) and relational certainty (Trivers, 1972). The large and consistent difference between maternal grandmothers and paternal grandfathers can be explained relatively directly based on relational uncertainty, as the maternal grandmother is the most certain that the grandchild is her genetic relative and the paternal grandfather is least certain. This explanation is widely accepted. However, the smaller but consistent differences in investment patterns by maternal grandfathers versus paternal grandmothers, in favor of the former, is not as easily explained. The two currently competing theories are as follows: (1) although maternal grandfathers and paternal grandmothers are equally uncertain of their relatedness, they invest differently depending on which generation their uncertainty lies in &ndash; the grandparent generation for the grandfather and the parent generation for the grandmother; and (2) paternal grandparents have other grandchildren for which they are maternal grandparents, and they will choose to invest more in these more certain relatives. The current research was designed to test a new hypothesis, that patterns of grandparent investment are affected by whether or not grandparents are nested (coupled and sharing resources). A survey measuring grandparent investment across four dimensions was administered and found no significant differences between certain nested and unnested grandparents in terms of investment. Results instead revealed a different overall pattern of investment entirely, indicating multiple design flaws and providing some direction for future research.</p>

<p> The larval nutritional mode of marine invertebrates is an important life history trait that has strong effects on their ecology and evolution. Increases in egg size and transitions from feeding to nonfeeding larvae have happened repeatedly. In Spiralia, a change in cytoplasm allocated to macromeres at the 8-cell stage (that could delay the development of a functional gut) may accompany these transitions. The first part of this thesis describes the development of the gastropod <i>Crepidula williamsi</i> and compares it to the closely related <i>C. fornicata,</i> with a focus on changes in allocation to macromeres and the development of a functional gut. The second part is a phylogenetic comparison of egg size and allocation to macromeres in 44 species of spiralians, which revealed a significant correlation between the two. A phylogenetic comparison like this one has not previously been done on the development of such diverse marine invertebrate taxa.</p>

Although population genetics has a long history and firm theoretical basis, until recently little data was available for empirical hypothesis testing. The unprecedented growth of sequencing methodologies has transformed the discipline from data-poor and theory rich field into one virtually unlimited by the available of suitable data. In this thesis, we develop bioinformatic methods to address a variety of longstanding questions in the field of evolutionary genetics. Specifically, we use data derived from model organisms to study the evolution of inversion polymorphisms, segregation distorters and fitness epistasis. In the first chapter, we develop methods for detecting chromosomal inversions using next-generation sequencing data. Subsequently, we show that chromosomal inversions in Drosophila melanogaster are evolutionarily young, and at least one has likely achieved polymorphic frequencies via sex-ratio segregation distortion. In the third chapter, we develop a method of surveying the genome for segregation distortion in an unbiased manner, and show that segregation distortion does not contribute to hybrid male sterility in one pair of house mouse populations. Finally, we show that contrary to expectations, gene-gene interactions are widespread within species, which challenges a central paradigm of speciation research.

<p> At its core human evolutionary biology seeks to answer the question of how the defining characteristics of modern humans evolved, such as large-brains, obligatory bipedal gait, extended juvenile period, and increased longevity. Traditional fossil-based research uses morphology to infer behavior and life history and only recently have researchers been able to make predictions regarding the effect of modifications to the DNA and proteins of our forbearers. Using these innovative methods we investigated the molecular evolution of a superfamily of transcription factors called the Nuclear Receptors. The patterns of sequence evolution observed in our bioinformatic analyses suggest a shift in the intensity of selection pressure occurred on <i>NR2C1</i>, a gene that plays a role early in embryonic stem cell proliferation and neuronal differentiation. Methods are now available to reconstruct ancestral DNA and its corresponding protein sequences and thus generate testable hypotheses about the functional evolution of genes on specific lineages. These methods allowed us to analyze how modifications to the modern human version of <i> NR2C1</i> affected the ability of an embryonic stem cell to remain in its proliferative state. We began by creating three different copies of our gene of interest: the human copy, the chimpanzee copy, and the ancestral copy of <i>NR2C1</i> for the inferred last common ancestor of chimpanzee and modern humans. Inserting these three different gene variants into mouse embryonic stem cells that have had NR2C1 knocked down allowed us to quantitatively analyze the transcriptional and regulatory functions of <i>NR2C1</i>. </p>

A study of the marine dinoflagellate Glenodinium foliaceum is presented which attempts to provide information on the process of host-endosymbiont integration in a unicellular system that may be of relevance to current hypotheses on chloroplast evolution. An experimental ultrastructural review of G. foliaceum supports the proposal that the chloroplasts and supernumerary nucleus belong to a morphologically reduced, endosymbiotic chromophyte. DAPI staining shows that the endosymbiont nucleus is fragmented in some cells and appears to be randomly divided by the host's cleavage furrow at cytokinesis. A quantification of the intensity of mithramycin fluorescence from single cells by flow cytometry suggests that both nuclei synthesize their ENA in synchrony. Protocols are outlined for isolating the chloroplasts and dinoflagellate nucleus from G. foliaceum and a method is given for fractionating whole cell lysates to prepare chloroplast, host nuclear, and endosymbiont nuclear DNAs. It is estimated that the symbiont and dinoflagellate nuclei contain about 34 pg and 40 pg of ENA respectively. There is no evidence of amplified genesized ENA molecules in the symbiont nucleus. The results of preliminary re-association experiments show only the presence of highly repeated ENA and sequences of intermediate repetitiveness in total cell ENA, which together comprise about half the genome. The chloroplast DNA is shown to a molecular weight of approximately 103 kb by restriction endonuclease analysis but an attempt to localize the rbc S gene in either the chloroplast or nuclear DNAs using a cloned pea ENA probe proved unsuccessful. Two other anomalously pigmented dinoflagellates, Gyrodinium aureolum and Gymnodinium galatheanum, are demonstrated to lack endosymbionts by electron and fluorescence microscopy, but the atypical ultrastructural or cytological characters of their chloroplasts are considered to indicate an endosymbiotic origin. The possibility that Glenodinium foliaceum could evolve into a similar uninucleate species is discussed in relation to the conservation of genetic information for nuclear-encoded, chloro-plast proteins.

<p> This study examines how the different behavioral, environmental and physiological factors might be influencing the essential physiological trait of erythrocyte mean cell diameters (MCD). At present no other study has explored the effects of these factors. Erythrocyte MCD for 153 species were collected from recent literary sources and compared to erythrocyte MCDs collected by Gulliver (1875), genome sizes and spleen sizes were also collected from a variety of literary sources. This data was analyzed using R with phylogenetic generalized least square analyses against several different behavioral, environmental and physiological factors. From these analyses, I found that as mammal mass and length increase the erythrocyte MCD also increases and as mammals move into higher elevations and warmer climates erythrocyte MCD decreases. All other behavioral, environmental, and physiological factors did not have an influence on erythrocyte MCD. These data did not support hypotheses previously offered by the other studies done on erythrocytes. Further research needs to be conducted on this topic because other factors that influence erythrocyte MCD may still exist that were not examined in this study.</p><p>

Many laboratory speciation experiments have raised allopatric populations in different environments to determine whether reproductive isolation evolves as a by-product of adaptation. Few, however, have controlled for the effects of genetic drift, addressed the evolution of both pre- and postmating isolation, or investigated the conditions that promote or hamper the process. I present results of a long-term evolution experiment in which 12 replicate populations of Drosophila melanogaster independently evolved for more than 57 generations under alternative desiccation treatments (six control and six desiccation-selected populations). Specifically, I demonstrate the divergence between the desiccation and control populations of cuticular hydrocarbons, key traits that have been implicated in mate choice and sexual isolation in Drosophila. Despite this divergence, there was no detectable pre- or postmating isolation between the desiccation and control populations. Novel environments are generally thought to promote the evolution of reproductive isolation. Understanding the conditions that favour or hamper this remains a key challenge for speciation research.