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Full-Text Articles in Life Sciences
A Morphological Phylogeny Of Odonatoptera: Examining Missing Data In A Group With A Lot Of "Naturally" Missing Data, Robert James Erickson
A Morphological Phylogeny Of Odonatoptera: Examining Missing Data In A Group With A Lot Of "Naturally" Missing Data, Robert James Erickson
Theses and Dissertations
Odonatopera exhibit a wide diversity of morphologies for an ancient group of winged insects. A morphological matrix of 463 characters is compiled for 347 extant and fossil representatives used in parsimony analyses, implemented in TNT, to document arrangements of taxonomic groups above the family level. Missing data and other challenges approaches implemented and interpretation of the results. We employ a novel approach to testing monophyly relative to quantities of missing data for each taxon. Phylogenetic reconstructions recover patterns of monophyly and trends based on missing data. We discuss the implications of our findings on missing data as well as limitations …
Classification Of Planetary Craters Using Outline-Based Morphometrics, Thomas J. Slezak, Jani Radebaugh, Eric H. Christiansen, Mark C. Belk
Classification Of Planetary Craters Using Outline-Based Morphometrics, Thomas J. Slezak, Jani Radebaugh, Eric H. Christiansen, Mark C. Belk
Faculty Publications
The morphologies of craters on planetary surfaces reveal clues about the geologic mechanisms by which they originate and subsequently evolve, as well as the materials and physical variables inherent to the environment in which they formed. We carried out a quantitative multivariate analysis of shape descriptors derived from the outlines of craters formed by volcanic processes on Mars, Io, and Earth and by impact cratering on the Moon using elliptic Fourier analysis (EFA) and the Zahn-Roskies (Z-R) shape function. Canonical variate analysis (CVA) was used to construct a statistical model of differences between the crater groups to classify …
Does Negative Frequency-Dependent Selection Maintain Gonopodial Asymmetry In A Livebearing Fish?, Mary-Elise Johnson
Does Negative Frequency-Dependent Selection Maintain Gonopodial Asymmetry In A Livebearing Fish?, Mary-Elise Johnson
Undergraduate Honors Theses
How genetic variation is maintained in the face of strong natural selection is an important problem in evolutionary biology. Selection should erode genetic diversity, leading to more and more homogeneous populations. Yet in nature, we commonly see high degrees of genetic variation, even for traits that are important to fitness. Negative frequency-dependent selection, a balancing selective force that favors traits when they are rare but not when they are common, is a mechanism proposed to maintain polymorphisms in a population. However, there is little empirical data to demonstrate how negative frequency-dependent selection sustains variation. Xenophallus umbratilis is a bilaterally symmetrical …