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Full-Text Articles in Comparative and Evolutionary Physiology

The Evolution Of The Stress Response In The Trinidadian Killifish: Ecological Drivers And Maternal Mediation, Mikaela E. Feder Jan 2025

The Evolution Of The Stress Response In The Trinidadian Killifish: Ecological Drivers And Maternal Mediation, Mikaela E. Feder

Biology Dissertations - Archive

Ecological variables can induce the stress response in organisms. Yet, few studies have tested for evolutionary shifts in stress responses across ecological gradients. In these studies, we used Trinidadian killifish found in sites with predators (high predation, HP) and sites where they are the only fish present (killifish only, KO). HP and KO populations differ in a suite of behavioral and life-history traits, making the Trinidadian killifish an excellent model to examine evolutionary physiology. My dissertation addresses the knowledge gap by examining: (1) how baseline cortisol differs in wild-caught Trinidadian killifish found in HP and KO sites, (2) the influence …


Study Of The Brain Anatomy Of Three Extinct Marsupials: Thylacinus Cynocephalus, Thylacoleo Carnifex, And Silvabestius Johnnilandi, Francisco Garcia Dec 2024

Study Of The Brain Anatomy Of Three Extinct Marsupials: Thylacinus Cynocephalus, Thylacoleo Carnifex, And Silvabestius Johnnilandi, Francisco Garcia

Honors Program Theses and Research Projects

Marsupials are pouched mammals that today are mainly found in Australasia and South America. Marsupials have proven to be quite intriguing to evolutionary biologists who note how some marsupials resemble placentals in anatomy due to convergent evolution, with both marsupials and placentals filling similar niches in their respective environments. As of today, studies interested in marsupial brain evolution have published descriptions of cranial endocasts for several species of marsupials, with the number of descriptions seeing a massive boost over the last 20 years with the arrival of CT imaging technology. However, no comprehensive study of brain evolution in marsupials has …


Morphological Variance In Mouthparts And Foraging Behavior In Bumblebees, Ye Jin Lee Jan 2021

Morphological Variance In Mouthparts And Foraging Behavior In Bumblebees, Ye Jin Lee

Honors Theses

Bumblebees (Hymenoptera: Apidae: Bombus) show an incredible degree of size variation within and between species. Individuals from the same hive may vary up to 10-fold in mass. This variation allows individuals to specialize in foraging on different flowers suited to their morphology. However, as different species have different foraging behaviors, their variation in mouthparts and scaling of mouthparts to body size may have been under different kinds of stabilizing selection as they adapted to collect nectar from flowering plants over evolutionary time. Here, we examined the scaling relationships between body size and mouthpart structures, and the variation in mouthpart shape …


Power Amplification Strategies Across Animals, Rayhan Asif Jan 2021

Power Amplification Strategies Across Animals, Rayhan Asif

Williams Honors College, Honors Research Projects

Animals use muscles for movement, but some have evolved mechanisms to exceed maximum power used in a motion known as power amplification. In this literature review, I analyzed and compared the evolution of structures capable of power amplification between species. Structures capable of power amplification were broken down into the basic components of the engine, amplifier, and tool. The species analyzed were found to possess necessary structures for power amplification which were relatively similar to each other in morphology, but varied greatly in function. The ease with which these structures evolved was evaluated based on the amount of divergence which …


A Tale Of Winglets: Evolution Of Flight Morphology In Stick Insects, Yu Zeng, Connor O'Malley, Sonal Singhal, Faszly Rahim, Sehoon Park, Xin Chen, Robert Dudley Jan 2020

A Tale Of Winglets: Evolution Of Flight Morphology In Stick Insects, Yu Zeng, Connor O'Malley, Sonal Singhal, Faszly Rahim, Sehoon Park, Xin Chen, Robert Dudley

Publications and Research

The evolutionary transition between winglessness and a full-winged morphology requires selective advantage for intermediate forms. Conversely, repeated secondary wing reductions among the pterygotes indicates relaxation of such selection. However, evolutionary trajectories of such transitions are not well-characterized. The stick insects (Phasmatodea) exhibit diverse wing sizes at both interspecific and intersexual levels, and thus provide a system for examining how selection on flight capability, along with other selective forces, drives the evolution of flight-related morphology. Here, we examine variation in relevant morphology for stick insects using data from 1,100+ individuals representing 765 species. Although wing size varies along a continuous spectrum, …


The Evolution Of Dragons, Laura J. Mayfield Jan 2020

The Evolution Of Dragons, Laura J. Mayfield

Undergraduate Theses, Professional Papers, and Capstone Artifacts

Dragons have been depicted in human art as early as 4500 BCE. For centuries, these fantasy creatures have inspired countless folk and fantasy tales, as well as appearing in the art of different cultures around the world. Now there are thousands of different depictions of these huge, flying, fire-breathing lizards, but are any of them possible? In this study, I reference peer-reviewed scientific articles, phylogenetic analysis, and paleoart studies to create biologically-sound dragons. Basing the dragon lineage on a real branch of webbed-winged scansoriopterygids—an extinct family of climbing and gliding maniraptoran dinosaurs—I explored the possible wing-structure, fire-breathing abilities, and effects …


From Gibbons To Gymnasts: A Look At The Biomechanics And Neurophysiology Of Brachiation In Gibbons And Its Human Rediscovery, Emma Et Pennock May 2013

From Gibbons To Gymnasts: A Look At The Biomechanics And Neurophysiology Of Brachiation In Gibbons And Its Human Rediscovery, Emma Et Pennock

Student Works

This conference paper serves to examine the evolutionary linkages of a brachiating ancestor in humans, the biomechanical and neurophysiology of modern day brachiators, and the human rediscovery of this form of locomotion. Brachiation is arguably one of the most metabolically effective modes of travel by any organism and can be observed most meritoriously in Gibbons. The purpose of the research conducted for this paper was to encourage further exploration of the neurophysiological similarities and differences between humans and non-human primates. The hope is that in spurring more interest and research in this area, further possibilities for rehabilitating brain injury will …


The Complexity And Origins Of The Human Eye: A Brief Study On The Anatomy, Physiology, And Origin Of The Eye, Evan T. Sebastian Apr 2010

The Complexity And Origins Of The Human Eye: A Brief Study On The Anatomy, Physiology, And Origin Of The Eye, Evan T. Sebastian

Senior Honors Theses

The human eye has been the cause of much controversy in regards to its complexity and how the human eye came to be. Through following and discussing the anatomical and physiological functions of the eye, a better understanding of the argument of origins can be seen. The anatomy of the human eye and its many functions are clearly seen, through its complexity. When observing the intricacy of vision and all of the different aspects and connections, it does seem that the human eye is a miracle, no matter its origins. Major biological functions and processes occurring in the retina show …