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Full-Text Articles in Life Sciences

Assessment Of Genetic Diversity In Largetooth Sawfish, Pristis Pristis, Populations Over The 20th Century, Ann Fearing Dec 2020

Assessment Of Genetic Diversity In Largetooth Sawfish, Pristis Pristis, Populations Over The 20th Century, Ann Fearing

Master's Theses

The Critically Endangered Largetooth Sawfish, Pristis pristis, experienced global declines in range and abundance over the past century and Australia is now their last stronghold. This research aimed to understand whether these declines have been accompanied by a reduction in levels of genetic diversity. Using P. pristis tissue samples sourced from natural history specimens, three fragments (616-bp, 386-bp, 141-bp) in the mitochondrial DNA (mtDNA) control region were PCR-amplified. At each fragment, significant genetic structure was found in P. pristis overall (ΦST=0.946, N=9; 0.813, N=54; 0.771, N=99). The Indo-West Pacific and Atlantic/Eastern Pacific each harbor genetically distinct lineages of …


An Examination Of The Influence Of Multi-Scale Processes And Connectivity On The Population And Assemblage Dynamics Of Headwater Fishes, Josh P. Hubbell Dec 2020

An Examination Of The Influence Of Multi-Scale Processes And Connectivity On The Population And Assemblage Dynamics Of Headwater Fishes, Josh P. Hubbell

Dissertations

Typified by their branching pattern, headwaters are numerically abundant as the density of these habitats increases with increasing distance from the base of a dendritic river system. Connectivity among headwaters is complex, resulting in the spatial isolation of populations. Headwater specialists have evolved a suite of traits that permit these species to permanently reside within these habitats. The spatial configuration and connectivity of headwaters has repercussions for metapopulations and meta-assemblages. I investigated how multi-scale processes and connectivity influenced the patch occupancy, coexistence, movement ecology, population structure, and gene flow of headwater specialists. In chapter two, I used occupancy modeling to …


Patterns Of Genomic Introgression In Topminnow Hybrid Zones, Amanda F. Ray May 2020

Patterns Of Genomic Introgression In Topminnow Hybrid Zones, Amanda F. Ray

Honors Theses

Hybridization and introgression are two important evolutionary mechanisms that can increase genetic diversity. Interesting introgression patterns can form when parental species have genes that confer some adaptive benefit to the organism. The Fundulus notatus species complex contains species with various identifying characterisics. Fundulus notatus, the blackstripe topminnow, and Fundulus olivaceus, the blackspotted topminnow, are closely related and occupy many of the same rivers in their preferred niches. These two species often hybridize and form hybrid zones where their niches overlap. We studied two hybrid zones located in the Tombigbee River and Spring River. Within each hybrid zone, we …


Size At Maturation, Spawning Variability And Fecundity In The Queen Conch, Aliger Gigas, Richard S. Appeldoorn Jan 2020

Size At Maturation, Spawning Variability And Fecundity In The Queen Conch, Aliger Gigas, Richard S. Appeldoorn

Gulf and Caribbean Research

The queen conch (Aliger gigas) resource is one of the most important in the Caribbean. While aspects of queen conch reproduction have been studied, e.g., size—at—maturity, spawning season, and density—based Allee effects, there is little information on other important aspects. From 210 lipped queen conch collected off southwest Puerto Rico, histological examination of gonads showed that 50% maturation occurred at 9 mm lip thickness. Experimental caged queen conch held on a natural spawning ground were monitored across the spawning season to evaluate fecundity and its variability across individuals and between nominal density treatments (2,000 vs 143 conch/ha). Near …


Intraspecific Aggression Towards Common Bottlenose Dolphin Calves, Northern Gulf Of Mexico, Errol Ronje, Sarah Piwetz, Heidi Whitehead, Keith D. Mullin Jan 2020

Intraspecific Aggression Towards Common Bottlenose Dolphin Calves, Northern Gulf Of Mexico, Errol Ronje, Sarah Piwetz, Heidi Whitehead, Keith D. Mullin

Gulf and Caribbean Research

Infanticide has been widely documented throughout the animal kingdom, and has generally been viewed as an evolved, or adaptive behavior for the perpetrators. Infanticide motivated by increased sexual access to females with calves, or the elimination of potential genetic competition in the form of calf-directed aggression or infanticide, has been proposed for delphinids including killer whales, Indo-Pacific humpback dolphins, Guiana dolphins, and bottlenose dolphins. However, reports of intraspecific aggression towards bottlenose dolphin calves are relatively infrequent, and accounts of confirmed infanticide are rarer still. Reporting instances of intraspecific calf-directed aggression aids researchers to better understand the socio-behavioral context of these …