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Full-Text Articles in Life Sciences

Morphological Variation And Community Science In Orthoptera, Amy Byerly Jan 2022

Morphological Variation And Community Science In Orthoptera, Amy Byerly

Electronic Theses and Dissertations

Patterns of morphological divergence across species’ ranges provide insight into local adaptation and speciation. Here, we compare phenotypic divergence among 4,221 crickets from 337 populations of two related species of field cricket, Gryllus firmus and G. pennsylvanicus and their hybrids. We find that these species differ across their geographic range in key morphological traits, such as body size and ovipositor length, and we directly compare phenotype with genotype for a subset of crickets demonstrating nuclear genetic introgression, phenotypic intermediacy of hybrids, and essentially unidirectional mitochondrial introgression. We discuss how these morphological traits relate to life history differences between the species. …


Responses Of Arthropods To Fire And How Pollinators And Pollination Services Are Affected By Fire Severity, Blyssalyn V. Bieber Jan 2022

Responses Of Arthropods To Fire And How Pollinators And Pollination Services Are Affected By Fire Severity, Blyssalyn V. Bieber

Electronic Theses and Dissertations

Fires impact ecosystems globally and due to climate change, there are shifts in fire regimes that impact ecological communities which provide essential ecosystem services. Focusing on arthropods, fire can influence this ubiquitous animal group in various way. We performed a comprehensive meta-analysis evaluating how fires impact differing arthropod functional groups. We found that overall, fire negatively effects community level responses for most functional groups with herbivores as the only exception showing some positive effects of fire. We also studied mixed-severity fires that burned >20 years ago and compared floral visitor communities across fire severities. We implemented a pollinator exclusion experiment …


Environmental Gradients Impact Key Leaf Traits In Riparian Trees, Amanda Malone Jan 2022

Environmental Gradients Impact Key Leaf Traits In Riparian Trees, Amanda Malone

Electronic Theses and Dissertations

Specific leaf area (SLA) reflects a plant’s carbon investment per area and relates to generalized leaf economics spectrum growth strategies (LES). To fill gaps of knowledge about intraspecific SLA variation and why it is often inconsistent with the LES, we studied the response of two riparian tree species along the urban-rural gradient in Northeastern Colorado: an invasive, nitrogen-fixer with broad tolerances and a nitrogen-limited and shade-intolerant native. Despite these differences, the two species responded similarly, apart from the response to the urban-rural gradient, in which lower nitrogen in rural areas was associated with a more conservative strategy in the native …


Understanding Patterns And Functional Impacts Of An Invasive Tree And Its Biological Control In A Riparian System, Annie L. Henry Jan 2021

Understanding Patterns And Functional Impacts Of An Invasive Tree And Its Biological Control In A Riparian System, Annie L. Henry

Electronic Theses and Dissertations

Invasive species have become an inextricable part of the landscape, particularly in riparian plant communities, and removal is often a key component of restoration programs. Biological control (biocontrol) is a method of removal that is often both efficient and effective. However, the impact of biocontrol on target species and indirect effects from invasive species removal can be hard to predict. While monitoring the impact of invasive species removal usually involves some species-based assessment such as changes in diversity, historically dominant species or native species, these strategies do not typically provide insight into the mechanisms underlying plant community response to removal. …


Cellular And Developmental Insights Into The Early Evolution Of Muscle, Jeffrey J. Colgren Jan 2020

Cellular And Developmental Insights Into The Early Evolution Of Muscle, Jeffrey J. Colgren

Electronic Theses and Dissertations

Whereas a great deal has been learned about the molecular underpinnings of morphological evolution in animals, much less is known about the origin of novel cell and tissue types. During the time in which the earliest animal lineages were diversifying, fundamental cell and tissue types, such as muscles, arose. Sponges are one of two animal lineages that lack muscles, yet they undergo coordinated full body contractions. Whereas the signaling processes have been studied, the physical mechanisms of contraction are completely uncharacterized. The main purpose of this work is to understand the primary contractile tissue of the sponge Ephydatia muelleri, …


Subalpine Forest Tree Seedling Response To Drought, Alex Goke Jan 2020

Subalpine Forest Tree Seedling Response To Drought, Alex Goke

Electronic Theses and Dissertations

Knowledge of tree species’ ability to tolerate drought is necessary to anticipate future forest dynamics with climate change, especially at the seedling stage given their role in shaping forest structure. We used precipitation reduction shelters to mimic drought for subalpine conifer seedlings (A. lasiocarpa and P. engelmannii) in the Rocky Mountains and compared survivorship and morphological and physiological responses to assess relative degrees of drought tolerance. We detected no significant investment in morphological tolerance traits (e.g. root biomass, leaf:stem area ratio) but substantial reductions in net photosynthesis. While shading partially ameliorated drought effects when precipitation reduction was moderate, …


Origins Of Animal Cell Adhesion, Jennyfer Mora Mitchell Jan 2018

Origins Of Animal Cell Adhesion, Jennyfer Mora Mitchell

Electronic Theses and Dissertations

A fundamental requirement for multicellularity is cell adhesion. This includes mechanisms by which cells adhere to each other and to their secreted extracellular matrix (ECM). Two well characterized adhesion complexes in animals include: 1) adherens junctions (AJs), which are involved in cell-cell adhesion and composed of cadherin receptors, p120-, α- and β-catenin, and 2) focal adhesions (FAs), which are involved in cell-ECM adhesion and include proteins such as integrins, vinculin, paxillin, talin and focal adhesion kinase (FAK). The molecular components of AJs are widely conserved in animals, and largely absent in non-animals. In contrast, the molecular components of FAs have …


Effects Of Anthropogenic Noise On Mating Behavior And Fitness, Gabrielle A. Gurule-Small Jan 2018

Effects Of Anthropogenic Noise On Mating Behavior And Fitness, Gabrielle A. Gurule-Small

Electronic Theses and Dissertations

When environments change rapidly, adaptive phenotypic plasticity can ameliorate negative effects of environmental change on survival and reproduction. Recent evidence, however, suggests that plastic responses to human induced environmental change are often maladaptive or insufficient to overcome novel selection pressures. Anthropogenic noise is a ubiquitous and expanding disturbance with demonstrated effects on fitness-related traits of animals like stress responses, foraging, vigilance, and pairing success. Elucidating the lifetime fitness effects of noise has been challenging because long-lived vertebrate systems are typically studied in this context. In both chapters described herein, I reared field crickets, Teleogryllus oceanicus, in masking traffic noise, …


Competition And Community Interactions Of Two Generalist Herbivores, Elizabeth Ellen Barnes Jan 2017

Competition And Community Interactions Of Two Generalist Herbivores, Elizabeth Ellen Barnes

Electronic Theses and Dissertations

Competition can have far-reaching consequences for the fitness and distribution of many organisms. In herbivorous insects, competition mediated by a third organism is more common than direct competition and has a strong effect on insect communities; yet most research on indirect competition among herbivores focuses on dietary specialists, and those studies that do include generalists tend to rear them on agricultural crops. My project examines species interactions at three levels: intraspecific competition (within species), interspecific competition (between species), and ecosystem engineering effects at the community level. I studied competition and community interactions of two temporally-separated species of herbivorous insects, western …