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University of Arkansas, Fayetteville

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Full-Text Articles in Comparative and Evolutionary Physiology

Robust Phylogenetic Regression, Richard Adams, Zoe Cain, Raquel Assis, Michael Degiorgio Jan 2024

Robust Phylogenetic Regression, Richard Adams, Zoe Cain, Raquel Assis, Michael Degiorgio

Entomology and Plant Pathology Faculty Publications and Presentations

Modern comparative biology owes much to phylogenetic regression. At its conception, this technique sparked a revolution that armed biologists with phylogenetic comparative methods (PCMs) for disentangling evolutionary correlations from those arising from hierarchical phylogenetic relationships. Over the past few decades, the phylogenetic regression framework has become a paradigm of modern comparative biology that has been widely embraced as a remedy for shared ancestry. However, recent evidence has shown doubt over the efficacy of phylogenetic regression, and PCMs more generally, with the suggestion that many of these methods fail to provide an adequate defense against unreplicated evolution—the primary justification for using …

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Expression Of Claudins In Gill And Opercular Membranes In Relation To Osmoregulation In Euryhaline Atlantic Killifish, Fundulus Heteroclitus, Allison Mcfarland Aug 2022

Expression Of Claudins In Gill And Opercular Membranes In Relation To Osmoregulation In Euryhaline Atlantic Killifish, Fundulus Heteroclitus, Allison Mcfarland

Graduate Theses and Dissertations

Atlantic killifish (Fundulus heteroclitus) are euryhaline teleosts, which means they can thrive in environments with varying salinities, ranging from concentrated seawater (SW) to dilute fresh water (FW) and thus survive in estuaries. To be able to maintain ionic and osmotic homeostasis in these diverse salinities, osmoregulatory organs like gill and opercular membrane must be able to adjust the permeability and transport of water and ions. The surface epithelia in these organs need to prevent the passive flux of ions and water in a drastically changing environment, while being able to switch between active ion secretion or uptake dependent upon environmental …

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Eastern Collared Lizard (Crotaphytus Collaris) Population Declines In Ozark Landscapes: An Assessment Of Environmental Constraints., Casey L. Brewster Dec 2019

Eastern Collared Lizard (Crotaphytus Collaris) Population Declines In Ozark Landscapes: An Assessment Of Environmental Constraints., Casey L. Brewster

Graduate Theses and Dissertations

The Eastern Collared Lizard (Crotaphytus collaris) has experienced extensive population declines over the past half century in the Ozark Mountains. Previous research suggests that glade habitat degradation through woody vegetation encroachment is an important factor resulting in population declines. In this dissertation I used information on time-energy budgets to investigate the link between habitat degradation and shifts in life history traits likely resulting in population declines of Eastern Collared Lizards (Crotaphytus collaris) in the Ozarks. In chapter one, I addressed the influence of dense woody vegetation encroachment on age-specific growth, body size, body condition and reproduction of C. collaris in …

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Histology Of Rathke’S Glands In The Razor-Backed Musk Turtle, Sternotherus Carinatus (Chelonia: Kinosternidae), With Comments On Lamellar Bodies, S. E. Trauth Jan 2017

Histology Of Rathke’S Glands In The Razor-Backed Musk Turtle, Sternotherus Carinatus (Chelonia: Kinosternidae), With Comments On Lamellar Bodies, S. E. Trauth

Journal of the Arkansas Academy of Science

I examined the histology and ultrastructure of Rathke’s glands in two adult male razor-backed musk turtles (Sternotherus carinatus) collected in northeastern Arkansas. This species possesses two pairs of Rathke’s glands that are embedded beneath marginal bones and are named according to their anatomical location (i.e., axillary and inguinal). These integumentary glands are similar anatomically to one another. Each gland is comprised of a single, highly vascularized secretory lobule, which is surrounded by a thin tunic of asymmetrically arranged, striated muscle. Two types of large secretory vacuoles characterize most of the holocrine cells produced by a relatively thin secretory …

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Validation Of The Use Of Doubly Labeled Water For Measuring Metabolic Rate In Timber Rattlesnakes (Crotalus Horridus), Caitlin Hirsh May 2016

Validation Of The Use Of Doubly Labeled Water For Measuring Metabolic Rate In Timber Rattlesnakes (Crotalus Horridus), Caitlin Hirsh

Biological Sciences Undergraduate Honors Theses

The doubly labeled water method is an isotopic technique for measuring field metabolic rate and water flux rates of free-living animals. We present a validation of the use doubly labeled water for measuring metabolic rate and water loss in Timber Rattlesnakes (Crotalus horridus). For this study seven animals of varying body size were used with masses ranging from 148 to 650 grams. Prior to dosing, blood samples were taken to establish background isotope levels for each animal. Snakes were injected with water enriched with isotopes of oxygen (18O) and hydrogen (2H, deuterium). The injected isotopes were then allowed to equilibrate …

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Systematics Of Protosteloid Amoebae, Lora Lindley Shadwick Dec 2011

Systematics Of Protosteloid Amoebae, Lora Lindley Shadwick

Graduate Theses and Dissertations

Because of their simple fruiting bodies consisting of one to a few spores atop a finely tapering stalk, protosteloid amoebae, previously called protostelids, were thought of as primitive members of the Eumycetozoa sensu Olive 1975. The studies presented here have precipitated a change in the way protosteloid amoebae are perceived in two ways: (1) by expanding their known habitat range and (2) by forcing us to think of them as amoebae that occasionally form fruiting bodies rather than as primitive fungus-like organisms. Prior to this work protosteloid amoebae were thought of as terrestrial organisms. Collection of substrates from aquatic habitats …

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