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Full-Text Articles in Life Sciences

Comparing The Reproductive Fitness Of Fundulus Hybrids And Their Parental Species (Fundulus Olivaceus And Fundulus Notatus) Within Mississippi Freshwater Contact Zones, Sarah Stovall Jun 2022

Comparing The Reproductive Fitness Of Fundulus Hybrids And Their Parental Species (Fundulus Olivaceus And Fundulus Notatus) Within Mississippi Freshwater Contact Zones, Sarah Stovall

Honors Theses

Hybridization of closely related taxonomic groups within the Animal Kingdom has led to complex species interactions that are not well understood. Pre-zygotic or post-zygotic barriers complicate hybridization as a means to diversify; however, diverging hybrids may speciate and expedite evolution of involved taxa. This study pursues understanding of these intricate interactions using topminnow Fundulus notatus, Fundulus olivaceus, and their hybrids from the Fundulus notatus species complex. Persisting hybrids within riverine contact zones were hypothesized to experience barriers of hybrid breakdown from lower fitness in comparison to the pure species. Specimens were collected within four contact zones: Spring River, …


Testing For Character Displacement Between Two Abundant Stream Fishes, Amber Nations Aug 2021

Testing For Character Displacement Between Two Abundant Stream Fishes, Amber Nations

Honors Theses

Character displacement is a pattern that can be used to explain differences between similar species in sympatric and allopatric situations. Gause’s Principle explains that a niche can only be occupied by one species at a time, so character displacement may be a way for similar species in the same habitat to shift resource use and compensate in order for the species to coexist. The Southeastern United States offers a unique opportunity to study this pattern because the diversity of freshwater fauna is quite high. However, the question of “How did this region become so diverse?” remains unanswered. One way for …


Morphological, Genetic, And Environmental Characterization Of An Unusual Population Of Isoetes (Isoetaceae, Lycopodiophyta), Shannon L. Walker Dec 2017

Morphological, Genetic, And Environmental Characterization Of An Unusual Population Of Isoetes (Isoetaceae, Lycopodiophyta), Shannon L. Walker

Honors Theses

A large and unusual population of Isoetes (Isoetaceae, Lycopodiophyta) in the DeSoto National Forest, Wayne County, Mississippi, was studied to determine if the individuals there represent a new species or if they represent part of the variation of the one primary species of the longleaf pine belt of Mississippi, Isoetes louisianensis, which it most closely resembles. The unusual population and specimens of known Isoetes louisianensis were examined comparatively based on morphology, megaspore ornamentation, examination of habitat characteristics, and phylogenetic analysis of DNA sequence data from the nuclear internal transcribed spacer 1 and 2 (ITS) and the 5.8S ribosomal gene. No …


The Evolution Of Body Size In The Order Siluriformes, D Cooper Campbell May 2015

The Evolution Of Body Size In The Order Siluriformes, D Cooper Campbell

Honors Theses

The evolution of body size has long been a topic of interest to biologists due to the close link between size and various aspects of an organism’s biology. Adult body size is influenced by the underlying tradeoff in energy allocation between maintenance, somatic growth and reproduction. I studied the evolution of a large group of globally distributed (primarily freshwater with some marine forms) fishes to test some basic hypotheses about the evolution of adult body size. Catfish (Siluriformes) are an excellent group for this type of research as they represent approximately 11% of fishes and species range in size from …