Spatiotemporal Environmental Variation and Its Effect on Diversity and Diversification at Macro- and Micro-evolutionary Scales

Spatiotemporal Environmental Variation and Its Effect on Diversity and Diversification at Macro- and Micro-evolutionary Scales
Author: Guinevere October Wogan
Publisher:
Total Pages: 414
Release: 2011
Genre:
ISBN:

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Species evolve in landscapes and environments that change through time. This spatial backdrop has profound effects on the diversification and merging of lineages. Populations become isolated by climate change, moving continents, and rising oceans, all of these factors can impact the evolutionary dynamics of lineages. While the spatial dimension of evolution has been a subject of interest since the inception of biogeography, the approaches to addressing how spatial heterogeneities affect lineages have advanced considerably in recent decades as genetic tools, computational tools, and new methodologies have allowed for explicit spatial hypotheses to be generated using GIS methods that can then be tested with genetic data. The focus of this dissertation examines amphibian evolution at deep temporal scales in relation to a changing global landscape, and sets the stage for examining the spatial dimension across the Asian landscape at shallow temporal scales. Chapter one investigates amphibian evolution and diversification within an explicit spatiotemporal framework in order to understand how spatial variation drives evolutionary patterns of amphibians at global scales. At macroevolutionary scales, global amphibian diversity is strongly correlated with the area of forest rather than the longevity of forests, and signatures of the extensive forest area of the Eocene underlies the dramatic amphibian latitudinal diversity gradient. Chapter two models the changing Asian landscape throughout the Pleistocene in order to understand how glacial and interglacial cycles impact the distribution of habitat types throughout the region. Satellite data on current habitats form the basis for this work. Palynological data are used to validate the models, providing a measure of confidence that the palaeo-predictive models are doing a good job in hind-casting habitats through changing climatic conditions. Asia differs from many other systems in not having been covered in extensive ice sheets during glacial periods, and provides a very different set of habitat dynamics, setting a unique stage for evolutionary dynamics. Habitats across Asia responded in dramatic fashion to changing palaeo-climates, with some habitats undergoing massive expansions and others contracting. The past 140 thousand years have witnessed a highly dynamic landscape. Chapter three delves deeper into palaeo-ecological modeling, and spatially locates stable habitat refugia across Asia for multiple tropical forest, temperate forest, and non-forested habitat types. These refugia are examined with respect to climatic stability and latitude to evaluate if stable climates give rise to stable habitats. Refugia are further examined with respect to terrestrial vertebrate species richness to understand if stable refugia have helped structure contemporary diversity patterns. Strong relationships between habitat stability and species richness were found, indicating that the spatial backdrop has played a pivotal role in contemporary diversity patterns. This indicates that these refugia may be important buffers against climate change and are probably important for the conservation of diversity in Asia. Chapter four focuses in on glacial and interglacial habitat dynamics on the Sundashelf, where dramatic changes in sea-level affect the connectivity of landmasses providing potential migration corridors between mainland SE Asia and insular Asia. I examine how these changing sea levels impact the distribution of habitats across the region and how in turn these habitat changes structure genetic data across the area. I found that high levels of genetic diversity correspond with stable habitats. Chapter five turns its attention to phylogenetics of the family Dicroglossidae, a widespread Old World frog family with high diversity across Asia. This chapter examines the generic assignments and familial monophyly and evaluates how nucleotide substitution models and partitioning affect the phylogenetic informativeness of markers and how this impacts phylogenetic inference. Both partitioning scheme and model selection were found to have profound effects on the phylogenetic informativenss of the genetic data. It was found that there are systemic biases among model selection criteria with the BIC commonly selecting highly parameterized models. It was also found that models of nucleotide substitution are often inadequate in capturing the complexity of empirical data. The monophyly of the Dicroglossidae was supported in these analyses. Many of the genera within the family were found to be monophyletic with the exceptions of the frogs of the Painii group and the Fejervarya. Together, these chapters provide the spatial foundation which sets the stage for research evaluating diversification processes in Dicroglossid frogs across the Old World and within Asia at biogeographic, phylogeographic and population genetics time scales. These analyses provide the first deeper time model-based evaluation of landscape processes for Asia.

Effects of Environment on the Evolution of Variation

Effects of Environment on the Evolution of Variation
Author: Genevieve Ann Metzger
Publisher:
Total Pages: 214
Release: 2016
Genre: Acinetobacter
ISBN: 9781369447088

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The role of spatial structure on the patterns and maintenance of diversity in populations is a longstanding area of research in evolutionary biology. The effects of spatial structure have been well documented in large eukaryotes but questions still remain about the influence of specific environmental factors on structure and how historic patterns of spatial structure influence modern distributions of diversity. At the level of microorganisms, research into the influence of spatial structure on diversity has recently begun to develop at a rapid pace. Previous studies have shown that spatial structure prevents selective sweeps in bacterial populations, increasing diversity by limiting competition between genotypes to a local, rather than global, scale. In this dissertation I seek to address questions of the influence of the environment, especially spatial structure, on the maintenance and pattern of diversity in two organisms: Ascaphus montanus, the Rocky Mountain tailed frog, and Acinetobacter baumannii, a biofilm-forming Gram-negative bacterium. In A. montanus I addressed the influence of environmental variables, incorporated through the use of Species Distribution Models, on the distribution of diversity at multiple spatial scales, from the entire species range, to within local clusters. Further, I used modeling based on estimates of past environmental conditions to investigate the role of historic separation of the species range into distinct glacial refugia affects current patterns of genetic diversity. I found that the influence of current vs. historic conditions varied based on spatial scale, with historic factors being most important at the largest spatial scale and modern environmental conditions being increasingly important at smaller spatial scales. In A. baumannii I utilized a large, replicated experimental evolution design to address the role of spatial structure due to biofilm growth and the presence or absence of an environmental variable, tetracycline, on evolution of both phenotype and genotypes of A. baumannii and the pB10 plasmid it carried. The presence of tetracycline did increase improvement of plasmid persistence in biofilms but did not alter genetic diversity of the plasmid or host. Growth in the spatially structured biofilm environment increased phenotypic diversity in the form of plasmid persistence, though it also limited the average strength of improvement in persistence. Biofilm growth also resulted in markedly different patterns in genetic diversity of the plasmid, with most plasmids that were isolated from the biofilm populations containing transferrable pB10. In contrast, only two plasmids isolated from the planktonic populations contained transferrable pB10. In the remaining plasmids large portions of the plasmid genome had been lost, resulting in loss of the genes involved in conjugation and making plasmid transfer impossible. This result suggests that spatial structure may dramatically modify the availability of plasmid genes in a population of bacteria compared to expectations based on studies performed with planktonic populations. Finally, I found that there were potential small differences in genetic diversity of A. baumannii itself, with more unique mutations found when comparing bacteria isolated from biofilms to those isolated from planktonic populations. As whole, these results confirm the importance of spatial structure and environmental variables on the evolution of diversity across multiple spatial and temporal scales and within widely differing organisms.

Connecting Microevolutionary Processes with Macroevolutionary Patterns Across Space and Time

Connecting Microevolutionary Processes with Macroevolutionary Patterns Across Space and Time
Author: Josef C. Uyeda
Publisher:
Total Pages: 282
Release: 2012
Genre: Body size
ISBN:

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Whether microevolutionary processes can explain macroevolutionary patterns has long been a matter of contentious debate. The debate has persisted largely because of the challenging task of connecting microevolutionary theory, which examines population-level phenomena on the generation scale, to data collected across larger spatial and temporal scales. My dissertation research broadly examines phenotypic evolution across multiple scales by connecting microevolutionary theory to macroevolutionary phenomena such as speciation and large-scale phenotypic change. In particular, I focus on the so-called "paradox of stasis"; which wrestles with the apparent conflict between frequently-observed cases of rapid evolution on short timescales and the frequent appearance of stasis in the fossil record. I attempt to link micro and macroevolution by using the theoretical framework of evolutionary quantitative genetics for modeling the effects of drift and selection. My four dissertation chapters examine four different systems (1) connecting quantitative genetic models of sexual selection to speciation (2) connecting microevolutionary and macroevolutionary body size data across scales of time (3) using phylogenetic comparative methods and quantitative genetic models to examine the evolution of a classic example of stasis, mammalian body temperature and (4) finally, using multi-locus phylogeography to understand the evolutionary processes that contribute to the diversification of a widespread snake across broad spatial scales. In chapter 2, I demonstrate that genetic drift combined with sexual selection can promotes speciation and diversification of male ornaments. Furthermore, I demonstrate that drift promotes the evolution of elaborate ornaments even when preferences are costly. In chapter 3, I combine data from microevolutionary field studies, the fossil record, and phylogenetic comparative data into a single analytical framework to resolve apparent conflicts between micro and macroevolutionary patterns. To do so, I compiled and analyzed the largest database of phenotypic divergence data in existence. I demonstrate that patterns of stasis persist until a million-year threshold, after which divergence begins to accumulate in a time-dependent manner. This pattern is best fit with a hierarchical model that describes evolution as occurring in bursts on the million-year timescale, but that allows for rapid, but bounded, evolution on short timescales. In chapter 4, I demonstrate that mammalian body temperature -- which has been previously presented as a classic example of stasis -- does in fact evolve extensively across the mammalian radiation (albeit slowly). Furthermore, I show that mammalian body temperature evolves in response to changing environmental conditions. Finally, I evaluate the role that genetic constraints play in the apparent slowness of body temperature evolution. In chapter 5, I examine a well-studied empirical system of garter snakes in which a strong signature of stabilizing selection has been found for phenotypic traits. Using multiple mitochondrial and nuclear loci, I show that introgression is rampant between species, and dynamic patterns of range expansion, contraction, and introgression among clades have led to a complex pattern of genetic variation. This structure of genetic variation underscores the need to examine range-wide processes for generating phenotypic divergence across clades. Overall, these chapters suggest that apparent disconnects between microevolutionary processes and macroevolutionary patterns could be explained by the scaling of population-level theory over large spatial and temporal scales.

Evolutionary Developmental Biology

Evolutionary Developmental Biology
Author: Laura Nuno de la Rosa
Publisher: Springer
Total Pages: 1000
Release: 2020-11-15
Genre: Science
ISBN: 9783319329772

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This reference work provides an comprehensive and easily accessible source of information on numerous aspects of Evolutionary Developmental Biology. The work provides an extended overview on the current state of the art of this interdisciplinary and dynamic scientific field. The work is organized in thematic sections, referring to the specific requirements and interests in each section in far detail. “Evolutionary Developmental Biology – A Reference Guide” is intended to provide a resource of knowledge for researchers engaged in evolutionary biology, developmental biology, theoretical biology, philosophy of sciences and history of biology.

Extreme Environmental Change and Evolution

Extreme Environmental Change and Evolution
Author: Ary A. Hoffmann
Publisher: Cambridge University Press
Total Pages: 276
Release: 1997-07-10
Genre: Science
ISBN: 9780521446594

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Most natural populations intermittently experience extremely stressful conditions. This book discusses how such conditions can cause periods of intense selection, increasing both phenotypic and genetic variation, and allowing organisms with novel characteristics to be first generated and then established in the population. The authors argue that stressful conditions can have a major impact on the environment, backing up their arguments with evidence from the fossil record. They suggest further that, as a consequence, periods of stress must be taken into consideration when long term conservation strategies are planned, particularly as stressful conditions are becoming increasingly prevalent as a result of human activities. This broad overview will be of great interest to students and researchers in the field of evolutionary biology, genetics, ecology, palaeontology and conservation biology.

Species Responses to Environmental Change at Multiple Scales

Species Responses to Environmental Change at Multiple Scales
Author: Roberta Pacheco Damasceno
Publisher:
Total Pages: 178
Release: 2013
Genre:
ISBN:

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In face of environmental changes, species, either move, changing their distributions, or maintain their ranges. Staying in place and facing the new conditions demand adjustments by changes in phenology, acclimation, via behavioral or phenotypic plasticity, or adaptation. Failure to adjust or move consequently leads to population decline and eventual extinction. The overarching goal of this work is to investigate the mechanisms by lizard species of two tropical genera, Leposom (Gymnophthalmidae) and Enyalius (Leiosauridae), respond to environmental changes at multiple spatial and temporal scales, in the Brazilian Atlantic Forest. I apply a highly integrative approach that combines species distribution modeling, climate data, phylogeography, morphology and thermal physiology and show (1) how geographic isolation, shifts in habitat use, and historical climatic stability explain the patterns of concordance/discordance between genetic divergence and phenotypic disparity in Leposoma scincoides, (2) how climatic variation and current environmental gradients, both at the macro- and microclimatic scales, affect thermal sensitivity across the two species' ranges and (3) how habitat suitability shape species' distribution ranges and spatial patterns of genetic structure in Enyalius catenatus and E. pictus . Despite deep phylogeographic structure in L. scincoides, and therefore ample opportunity for intra-specific lineages to diverge phenotypically, there is an overall pattern of phenotypic stasis in morphology and physiology. This is most likely due to similar environmental conditions acting on morphology at the climatically stable core of the distribution, and to constraints on thermal tolerances. However, geographically isolated lineages inhabiting more seasonal areas, that were unstable climatically during the Pleistocene, are morphologically distinct. Among those, similarity in morphology was observed between lineages that further broadened their habitat use, occupying more open areas as well as forested habitats. Moreover, morphological variation correlates with climate. These results highlight how distinct phenotypic traits likely to respond to environmental change show very different patterns of variation, conditional on evolutionary lability, plasticity and (possibly) interaction among traits. Macroclimatic data are not a good proxy for the environmental conditions experienced by the two lizard species in their microhabitats; there is great overlap in temperature availability in similar microhabitats along a macroclimatic gradient in the Central Brazilian Atlantic Forest and climate variables correlated with thermal physiological traits only at the microclimate scale. Both species show narrow thermal tolerances and differences in thermal physiology between the two species can explain some of their ecological differences. Thermal sensitivity is conserved among lineages within L. scincoides, whereas plasticity and acclimation are prominent in E. catenatus' thermal physiology, but the capacity to acclimate to extreme temperatures in the later is limited. These results are alarming if confronted with the rapid anthropogenic changes in habitat cover and climate change predicted to afflict this region. There is strong phylogeographic structure and high levels of genetic diversity in Enyalius catenatus and E. pictus. These results are consistent with the notion that in this region, Quaternary forest refuges provided stable climatic conditions that promoted persistence of phylogeographic diversity and stable populations. Nevertheless, divergence times, between E. catenatus and E. pictus and among intraspecific lineages, earlier than the late Pleistocene point to a long and complex history of diversification in Enyalius, that requires a variety of factors to explain spatial patterns of genetic structure. Instances of discordance between the species distribution models and genetic structure were pondered carefully in the context of ecological and natural history and the limitations of the models. My findings show that patterns and mechanisms of divergence and disparity are complex and multifaceted in this region, with geographic as well as ecological components playing important. This study presents an integrated approach to test evolutionary hypotheses that combine phylogeographic and phenotypic data and put it in the context of the landscape, taking into account geographic, environmental, and historical aspects of the habitat. It adds to the growing body of literature that explores phylogeographic patterns of prevalent elements of the Brazilian Atlantic Forest fauna and if/how they responded to climatic oscillations in the Pleistocene. More broadly, it contributes to the growing literature on South America's biogeography and the origin and maintenance of Neotropical diversity.

Spatiotemporal Variation in Animal Behavior, Species Interactions, and Their Impacts on Seed Dispersal Potential in a Novel Ecosystem

Spatiotemporal Variation in Animal Behavior, Species Interactions, and Their Impacts on Seed Dispersal Potential in a Novel Ecosystem
Author: Rebecca C. Wilcox
Publisher:
Total Pages: 196
Release: 2020
Genre: Animal behavior
ISBN:

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Animal-mediated seed dispersal is critical for maintaining the diversity of ecosystems. However, this mutualism is under threat from global environmental change. The loss of native species and the introduction of exotic species creates novel species interactions and can alter seed dispersal. Animal-mediated seed dispersal can vary across spatiotemporal scales owing to variation in the plants, dispersers, and the surrounding community, with impacts on seed dispersal. Therefore, examining key processes and behaviors relevant to seed dispersal is critical for understanding current and future seed dispersal in novel ecosystems. I conducted the following four studies in a novel seed dispersal system on Oahu, Hawaii. First, I examined space use patterns of an assemblage of exotic bird dispersers. I found redundant space use patterns in native dominated habitats, suggesting those habitats have a robust dispersal community. Second, I examined temporal variation in disperser behaviors relevant to seed dispersal. I found little temporal variation in frugivory and species foraged primarily on fruits in foraging aggregations during the non-breeding season. Third, I explored how temporal overlap in disperser availability and plant fruit availability impacts plant-disperser interactions. I found that temporal overlap within trophic levels (between plants) was more important than overlap between plants and dispersers for seed dispersal. Lastly, I examined movement patterns of dispersers. I found that both inter- and intra-specific variation were present suggesting the need to take this variation into account when modeling seed dispersal. Together, these studies highlight the need to incorporate variation and specific behaviors into studies of seed dispersal.

Patch Dynamics

Patch Dynamics
Author: Simon A. Levin
Publisher: Springer Science & Business Media
Total Pages: 324
Release: 2012-12-06
Genre: Science
ISBN: 3642501559

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From the preface by Joel E. Cohen: "A century from now humanity will live in a managed - or mismanaged - global garden. We are debating the need to preserve tropical forests. Farming of the sea is providing an increasing part of our fish supply. We are beginning to control atmospheric emissions. In 100 years, we shall use novel farming practices and genetic engineering of bacteria to manipulate the methane production of rice fields. The continental shelf will be providing food, energy, possibly even living space. To make such intensive management possible will require massive improvements in data collection and analysis, and especially in our concepts. A century hence we will live on a wired earth: the oceans and the crust of the earth will receive the same comprehensive monitoring now devoted to weather. As the peoples of currently developing countries increase their levels of wealth, the need for global management will become irresistible as impatience with the accidents of nature and intolerance of mismanagement of the environment - especially of living resources - grow. Our control of physical perturbations and chemical inputs to the environment will be judged by the consequences to living organisms and biological communities. How can we obtain the factual and theoretical foundation needed to move from our present, fragmented knowledge and limited abilities to a managed, global garden?" This problem was addressed in the lectures and workshops of a summer school on patch dynamics at Cornell University. The school emphasized the analysis and interpretation of spatial patterns in terrestrial and marine environments. This book contains the course material of this school, combining general reviews with specific applications.

The Ecological and Evolutionary Effects of Environmental Perturbations on Populations and Communities

The Ecological and Evolutionary Effects of Environmental Perturbations on Populations and Communities
Author:
Publisher:
Total Pages: 284
Release: 2016
Genre:
ISBN:

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Environmental perturbations can provide ideal situations to study eco-evolutionary dynamics (feedback loops between ecological and evolutionary interactions) on short timescales. Yet, studies of these dynamics in marine pelagic species, whose populations are not clearly defined, risk obscuring causal relationships. Studies of eco-evolutionary relationships in terrestrial and freshwater systems benefit from utilizing microcosms, which can act as 'natural laboratories' to allow better measures of the acting processes. Yet, only recently have marine systems been recognized to have analogous microcosms. I utilized one such marine microcosm - marine lakes - to study a contained population of a pelagic scyphozoan predator, Mastigias papua. Across the Indo-West Pacific, Mastigias spp. occurs in two distinct morphological ecotypes - ocean and lake - that occur locally proximate to one another, yet appear similar within ecotype across the region. I established the evolutionary history, locally and regionally, by reconstructing phylogenetic and intraspecific genetic relationships utilizing two nuclear (H3a, H3b) and three mitochondrial (COI, COIII, 16S) markers. Phylogenetic reconstruction was complemented by morphological characters to reconstruct the macroevolution of ecotypes and test three hypotheses that explain the geographic distribution of ecotypes. Periodic perturbations, consisting at least in part of a highly stratified layer of warmer and more saline water and the disappearance of the medusae stage of Mastigias, occur in the marine lakes. I examined the microevolutionary effects of one such event on the genetics, morphology and behavior in one Palauan lake population. I used the genetic data to exclude one possible hypothesis that explained the difference in morphology and behavior upon medusae return than before the perturbation event. Finally, I examined the associations between environmental factors and Mastigias medusa population size following another such perturbation in a different Palauan marine lake over a decade, as well as examined the associations between medusae and other microplankton population fluctuations. These studies build a foundation for eco-evolutionary work in marine systems. The comparative framework across spatial and temporal scales can elucidate patterns and processes that act in the marine realm. As climatic variability increases, it is increasingly important to understand the eco-evolutionary dynamic of systems and the potential impacts perturbations can have on those systems.

Accessing Uncultivated Microorganisms

Accessing Uncultivated Microorganisms
Author: Karsten Zengler
Publisher:
Total Pages: 332
Release: 2008
Genre: Science
ISBN: 9781555814069

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Providing a comprehensive overview and discussing developments in the field, this book details various innovative methods used in microbial ecology and environmental microbiology. It also includes all aspects of microbial diversity from bacteria and fungi to protists.