Browsing by Subject "adaptation"

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Aprendizaje invisible: Hacia una nueva ecología de la educación
(Laboratori de Mitjans Interactius / Publicacions i Edicions de la Universitat de Barcelona, 2011-04-15) Cobo, Cristóbal; Moravec, John W.
The proposed invisible learning concept is the result of several years of research and work to integrate diverse perspectives on a new paradigm of learning and human capital development that is especially relevant in the context of the 21st century. This view takes into account the impact of technological advances and changes in formal, non-formal, and informal education, in addition to the 'fuzzy' metaspaces in between. Within this approach, we explore a panorama of options for future development of education that is relevant today. Invisible Learning does not propose a theory, but rather establishes a metatheory capable of integrating different ideas and perspectives. This has been described as a protoparadigm, which is still in the 'beta' stage of construction.
Causes and consequences of evolutionary innovation: An experimental approach to evaluating assumptions and predictions in macroevolutionary theory
(2020-01) Gettle, Noah
It has long been noted that there are some adaptations that appear to have played a disproportionate role in determining the evolutionary trajectories of the clades in which they arose. These adaptations, often termed evolutionary innovations, are often associated with increases in diversity and expansions into new niche spaces. The historic nature of evolutionary innovations, however, largely limit our ability to draw conclusions about causes and consequences, leaving broad-scale explanations constrained to theory. Using the power of experimental evolution, this work aims to explore empircally theories concerning the origins and evolutionary consequences of innovations. I used one proposed innovation, multicellularity, a trait that reliably arises in brewers’ yeast (Saccharomyces cerevisiae) under certain selective conditions. Using genomic tools, I show that despite their disruptive nature, loss-of-function mutations in largely “non-regulatory genes” are the major causal genetic changes underpinning convergent evolution of experimental yeast populations toward multicellularity. I further show that one of these mutations is also associated with major transcriptional and physiological effects one of which, increased apoptosis, has been previously described as a multicellular adaptation. Data presented here suggests this is less likely a direct effect of loss of gene activity than of microenvironmental shifts associated with a multicellular lifestyle. Finally, I present research that suggests that adaptive responses to environmental challenges often associated with complex multicellularity, such as division of labor, may not represent optimal fitness solutions but rather reflect a balance between the costs and benefits of retained multicellularity. In sum, my results reveal that current theories regarding multicellularity as well as other innovations may, at best, be incomplete and that generalizations about causes and consequences of evolutionary innovations may prove more difficult to come by than many have suggested.
Climate-informed restoration of white pine: Impacts of seed source, planting site, and earthworms
(2016-11) Mead, Jordan
Habitat suitability for forest species is expected to shift with changes in climate, resulting in new and altered species assemblages. These alterations will be most notable near species boundaries, where feedbacks between disturbance, regeneration and recruitment are especially sensitive to temperature. How forest ecosystems respond will depend on the rate of climate change, dominant disturbance regime, the arrival of suitable propagules and the ability of those propagules to survive local climate, herbivory, invasive species and interspecific competition. Local adaptation of tree populations has been well documented in common garden experiments and may have a significant impact on the regeneration and recruitment in disturbed forests. In Northern Minnesota, USA, forest-climate models predict large-scale shifts in forest cover, and climate-driven changes in forest regeneration have already been documented at ecotone boundaries. Local populations of white pine (Pinus strobus) that are expected to increase may not be able to survive and reproduce successfully due to population bottlenecks, slow migration rates, habitat fragmentation, and intense herbivory. This is coupled with reduced reproduction of other temperate species, such as maples (Acer spp.), by herbivory and introduced detritivores. Given the rate of climate change, the migration and evolution of locally adapted populations and species are expected to lag behind optimal climate. My work documents restoration of white pine to assess the effects of seed source climate and site attributes, such as light environment and earthworm abundance, on survival, growth and phenology of planted seedlings. I also investigate the impacts and abundance of non-native earthworms in disturbed areas, as well as the surrounding intact forest to look for interactions between these invaders and disturbance. This data could be further used to improve models and inform management that will help sustain forest health and productivity.
The costs (and benefits) of standing out: Alternative reproductive behavior and novel trait evolution in the Pacific field cricket
(2021-07) Olzer, Rachel
Conspicuous animal signals are often under conflicting selection, with higher performance in one fitness component of life history diminishing performance in another component. The diversity of animal signals in nature suggests that novelty- a new structure or property of an organism that allows it to perform a different function, thus opening a new ‘adaptive zone’ is an important, but often overlooked aspect of signal evolution. The evolution of novelty has largely been absent from conversations about how diversity arises and how it can be maintained. This work seeks to examine both the causes and consequences of novel trait evolution. From individual behaviors to population-level dynamics, I have employed various methodologies for answering a decades-long question in evolutionary biology: how are novel traits accommodated in natural populations?
The evolution of plant functional variation: traits, spectra, and strategies
(University of Chicago Press, 2003) Reich, Peter B; Wright, I J; Cavender‐Bares, J; Craine, J M; Oleksyn, J; Westoby, M; Walters, M B
Variation in plant functional traits results from evolutionary and environmental drivers that operate at a variety of different scales, which makes it a challenge to differentiate among them. In this article we describe patterns of functional trait variation and trait correlations within and among habitats in relation to several environmental and trade‐off axes. We then ask whether such patterns reflect natural selection and can be considered plant strategies. In so doing we highlight evidence that demonstrates that (1) patterns of trait variation across resource and environmental gradients (light, water, nutrients, and temperature) probably reflect adaptation, (2) plant trait variation typically involves multiple‐correlated traits that arise because of inevitable trade‐offs among traits and across levels of whole‐plant integration and that must be understood from a whole‐plant perspective, and (3) such adaptation may be globally generalizable for like conditions; i.e., the set of traits (collections of traits in syndromes) of taxa can be considered as “plant strategies.”
Examining Decision-Makers’ Perspectives on Climate Change and Climate Preparedness in the Lake Superior Basin of Minnesota
(2017-05) Meier, Holly
This study explores characterizations of climate change and climate preparedness within two subwatersheds of the Lake Superior basin. Twenty-seven key informant interviews were conducted with local decision makers, resource managers, and other leaders active in the subwatersheds. Study participants’ experiences, beliefs, and attitudes were documented and analyzed using qualitative methods. Findings indicate strong convergence around climate change beliefs and concerns and divergence on perspectives on climate preparedness. Further analysis revealed specific challenges and current actions associated with climate preparedness. A better understanding of climate change beliefs and perceived preparedness will provide insight into the resources and activities that can be leveraged for further climate preparedness. This study also reveals challenges that may need to be addressed to make efforts more effective. Study findings offer a framework for climate preparedness planning and provide evidence for a strategic approach to building adaptive capacity in the study communities. Findings will inform community engagement, outreach, education, and communication programming on climate preparedness.
Fitness and Adaptive Capacity in a Minnesota Prairie
(2016-12) Eule-Nashoba, Amber
Wild populations are subject to environments that are changing at unprecedented rates. Assessing natural selection and the capacity to adapt in wild populations is crucial to planning for and understanding how species will fare under climate change. The goal of this research was to empirically examine selection and adaptive capacity in a natural population of Chamaecrista fasciculata. In Chapter 1, I present an empirical quantitative genetic study of C. fasciculata to predict the rate of change in mean fitness using Fisher’s Fundamental Theorem of Natural Selection (FTNS). The additive genetic variance for fitness was found to be substantial and statistically significant in both 2013 and 2014. Application of FTNS predicts increases in mean fitness of 1.68 (2013) seeds and 8.08 (2014) seeds in the next generation. These findings demonstrate that this population has the genetic capacity to respond to natural selection and is predicted to increase in fitness and thus, become better adapted to their environment. The objective of Chapter 2 is to compare predicted and observed mean fitness of C. fasciculata in a natural selective environment. Observed mean fitness of both second-generation cohorts was, however, lower than predicted by the FTNS and lower than their respective first-generation cohorts. However, comparison of first and second-generation cohorts growing in the same year and, hence, common conditions, demonstrated an increase in mean fitness. Thus, environmental differences between years, as well as genotype-by-environment interaction, contribute to the deviation of observed from predicted mean fitness. In Chapter 3, I performed a quantitative genetic study of phenotypic selection on C. fasciculata to examine the effect of selection and environment on the phenology of germination and reproductive initiation. In this population, selection for advancement in reproductive stage was detected, as well as a response of 2.2 days earlier flowering in the second generation. Overall, findings of these chapters present a population that has demonstrated a response to selection in flowering phenology and significant genetic variation for evolutionary fitness. This evidence of adaptation and substantial adaptive capacity conveys crucial information regarding the likelihood of population persistence, information that could be utilized for other species towards conservation goals.
From individuals to species: how natural selection and phenotypic plasticity shape ecomorphological evolution in freshwater mussels
(2023-05) Keogh, Sean
Adaptation is the hallmark of evolutionary biology, explaining how species achieve ecological success through natural selection. However, adaptation is challenging to identify leading to frequent ‘just-so stories’ to explain the adaptive features of organisms. At the core of adaptive studies is the motivation to find the fit between morphological and functional diversity. Here I used the freshwater mussels of North America as a study system to investigate the fit between morphological and ecological traits both within and across species. I used comparative and experimental inferences to identify the evolutionary mechanisms driving ecomorphological patterns. My first chapter identified ecomorphological patterns within and across species between shell thickness, shell anterior thickening, and flow rate. Across species, I found widespread convergence in these traits showing that natural selection produces the following adaptations to riverine flow rates: thick and anteriorly thickened shells in high flow rates (likely for stability in the substratum) and thin and uniformly thickened shells in low flow rates (likely for burrowing efficiency). Additionally, within species, I found a creditably positive relationship between shell thickness and flow rate, effectively mirroring interspecific relationships albeit at different scales. Intraspecific processes may therefore be partially responsible for the evolvability and ecological diversification of the clade. Although I identified this intraspecific ecomorphological pattern, I could not identify the mechanism producing this pattern. To address this, in my second chapter I conducted a common garden experiment on a morphologically variable species, Pyganodon grandis. The morphology of this species varies predictably between lake and stream environments and I investigated if this relationship was due to phenotypic plasticity or genetic differentiation. By rearing siblings from a single female’s broodstock, I minimized genetic variation, and released ~6,000 marked individuals into nine sites (four streams, five lakes). Two years after release, I recaptured a total of 70 individuals from both stream and lake sites showing significant shell shape differences between habitats and no shell shape differences between recaptured siblings and wild P. grandis reared at the same site, showing definitively that phenotypic plasticity rather than genetic differentiation is driving ecomorphological patterns. In my third and final chapter I ran a fluvial experiment investigating the function of mussel posterior ‘ribbed’ sculpture. I measured water velocity magnitude, direction, and streambed erosion surrounding mussel models with sculpture and with their sculpture manually removed. In opposition to previous studies, I found more streambed erosion associated with sculptured models. However, mussel orientation to streamflow was the more significant driver to variations in water velocity magnitude, direction, and streambed erosion. This body of work illustrates the complementary nature of phylogenetic comparative methods and experiments to finding the evolutionary mechanisms of phenotypic variation. Lastly, the role of phenotypic plasticity in macroevolutionary outcomes has seldom been investigated but the widespread convergence of ecomorphological traits in chapter 1 and common garden experiment in chapter 2 suggest plasticity may be a key mechanism to macroevolutionary diversification.
The hidden costs of rapid adaptation: experimentally assessing the effects of standing variation on the pace and trajectory of evolution
(2022-03) Griffin, Josie
As the planet changes at an alarming rate, there is a great need to understand why some populations are better equipped to rapidly adapt to their new environment than others. Many factors contribute, but populations are ultimately limited in their pace by their genetic makeup—they either have variants that allow them to survive or they do not. But, in the race to adapt, all sources of variation are not equal, and standing genetic variation is theorized to be of the most benefit in contributing to rapid adaptation. Here I explore the role of standing variation, both in a population’s ability to adapt at a rapid pace and in the potential long term evolutionary consequences that occur as a result. My work confirms expectations that increased standing variation in a population allows for a faster rate of adaptation, but although these populations are able to succeed in the short term, but this achievement comes at a significant cost to long term viability. All populations, across all experiments, that utilize standing variation as the genetic basis for rapid adaptation lose the ability to undergo sexual recombination, and therefore lose an important mechanism for maintaining variation in the long term. I begin by determining how the amount of standing variation present in a population correlates to the timing and rate of a successful adaptive response to a stressful environment. I assess how this result is intertwined with loss of sex and explore the mechanism for that loss. Then, I explore how the dynamics of the system change if the environmental shift occurs gradually rather than as a dramatic climactic event. Finally, I compare the variety of evolutionary strategies that develop in populations that began with standing variation versus mutation as their genetic substrate and evaluate their potential for success in the long term. Taken together, these results present a different picture of the role of standing variation than might be assumed. It does indeed allow for rapid adaptation, but the increased degree of genetic variation is not an evolutionary panacea and may send populations down evolutionary trajectories that are short-sighted.
I Will Not Be a Monster": Revising the Fairy-Tale Witch"
(2023-04) Zimmerman Zuckerman, Ali
The image of the evil, ugly, old woman with dangerous magical powers has long been the dominant representation of the fairy-tale witch. But, in recent years, an alternative tradition has been gaining ground. In this dissertation, I ask: How have modern authors revised and rehabilitated the character of the fairy-tale witch? What narrative strategies have they created in the process of adapting this familiar character? How do they attempt to transform cultural attitudes toward the fairy tale and its witch? In Chapter 1, I draw on Brian Attebery’s theorization of fuzzy generic sets, Marek Oziewicz’s interpretation of cognitive scripts, and Jack Zipes’s application of cultural memes to argue that fairy tales and their witches are clear, yet flexible, cognitive categories that influence cultural behaviors and beliefs. In Chapter 2, I focus on Emma Donoghue’s Kissing the Witch (1993). I argue that Donoghue undermines the dichotomy between wicked witch and virtuous princess. As a result, she queers cultural understandings of the fairy tale. In Chapter 3, I take Neil Gaiman’s “Snow, Glass, Apples” (1994), Barbara Walker’s “Snow Night” (1996), and Mercedes Lackey’s The Sleeping Beauty (2010) as case studies for essentialist fairy-tale texts: narratives in which morality is fixed and absolute. In Chapter 4, I analyze ABC’s television drama Once Upon a Time (2011–2018) as a non-essentialist text: a narrative in which morality is flexible and dynamic. I argue that essentialist witches reinforce an older moral framework that imagines black-and-white distinctions between virtue and villainy, while non-essentialist witches encourage us to reconsider our inherited ideas about goodness and wickedness. Ultimately, this project explores the ways in which modern authors and artists have combined the traditional with the subversive in order to shape a new landscape for the fairy-tale witch.
Nautical Affordances for Walking
(2019-08) Walter, Hannah
I investigated the perception of affordance that emerge from dynamic aspects of humans (lateral oscillations of the body during walking) and the environment (angular motion of the ground). I chose to focus on the ways in which motion of ships at sea may influence how humans detect their affordances. Humans going out to sea for thousands of years, yet very little research has addressed perception and action at sea. I conducted several affordance experiments at sea to begin filling the large gap in human movement literature. I chose to investigate the affordance of walking on the deck within the confines of a pathway. In Experiment 1, I asked seasoned mariners to estimate their ability to walk within a set pathway. Upon completion of these judgments, the mariners were then asked to perform the walking task. The results showed that mariners’ judgments were accurate. In Experiment 2, I built off of this success, repeating the same design across daily changes in ship angular motion. Judgments accurately reflected these daily changes. Finally, in Experiments 3 and 4, I took a different approach. While the two previous experiments utilized the natural ship motion (environmental factor) to change the affordance, in Experiments 3 and 4 I used weights added to the participant (animal factor) to manipulate affordances for walking. I first established that added weight influenced affordance judgments on land. I then found similar effects on a ship at sea. Taken together, my experiments expand our understanding of perceptual sensitivity to affordances that arise from dynamic properties in the animal-environment system. Additionally, many implications concerning nautical performance and safety can be gleaned from this study.
Place meanings and climate change vulnerability: Nature-based recreation and tourism community leaders contemplate change
(2017-11) Katz, Karen
Climate change adaptation has largely failed to address the importance of changing place meanings in nature based-recreation and tourism (NRT) communities. Twenty-five semi-structured interviews and three focus groups were conducted with community leaders (e.g., residents that were tourism professionals, natural resource managers, and local elected officials) on the “North Shore” of Lake Superior in Minnesota, USA. These qualitative data were analyzed using grounded theory methods. Perceptions of local effects of climate change diverged: stakeholders felt vulnerable, had perceptions of resilience or lacked understanding of impacts. Climate change threatens to cause reduced place satisfaction (vulnerability) and is determined by the level of place dependence (exposure) and the degree of place identity (sensitivity) in the NRT community. This study proposes a theoretical model integrating place concepts and climate change vulnerability that addresses the overlooked role of place meanings and identity in climate change adaptation.
Ready Or Not: On The Climate Vulnerability Of Sport Organizations
(2020-05) Orr, Madeleine
Since the 1970s, North America has experienced warmer and wetter winters, and more frequent extreme weather events such as hurricanes and heat waves. These climate shifts have carried consequences for the business and performance of sport at all levels, such as event cancellations, decreased participation rates, and facility damages. In the format of three articles, this dissertation examines sport organizations’ climate vulnerability. The first article (Chapter 2) reviews the extant literature on sport and the natural environment, advances two sport-specific constructs for climate vulnerability: climate impacts on organizations (CIO) and organizational climate capacity (OCC), and proposed a framework that graphically represents the various states of vulnerability an organization may face based on the organization’s exposure to hazards, sensitivity to hazards, and capacity to respond. The second article (Chapter 3) presents a qualitative study using 16 semi-structured interviews with sport practitioners whose organizations have recently faced climate hazards, to determine dimensions for OCC. Findings revealed the dimensions of OCC are infrastructural resources, natural resources, planning and development resources, human resources, financial resources, and network and relationship resources. These dimensions bear resemblance to the dimensions of organizational capacity and adaptive capacity, adopting five dimensions from organizational capacity and the natural environment focus of adaptive capacity. In the third article (Chapter 4), the construct of OCC is operationalized beyond a set of dimensions into a list of 77 indicators, organized by dimensions. This list of indicators was developed through an online Delphi study involving 25 academic experts in sport management, and represents an important step in rendering the construct more applicable and understandable for sport managers.

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