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Full-Text Articles in Biology
Life History Divergence In Livebearing Fishes In Response To Predation: Is There A Microevolution To Macroevolution Barrier?, Mark C. Belk, Spencer J. Ingley, Jerald B. Johnson
Life History Divergence In Livebearing Fishes In Response To Predation: Is There A Microevolution To Macroevolution Barrier?, Mark C. Belk, Spencer J. Ingley, Jerald B. Johnson
Faculty Publications
A central problem in evolutionary biology is to determine whether adaptive phenotypic variation within species (microevolution) ultimately gives rise to new species (macroevolution). Predation environment can select for trait divergence among populations within species. The implied hypothesis is that the selection resulting from predation environment that creates population divergence within species would continue across the speciation boundary such that patterns of divergence after speciation would be a magnified accumulation of the trait variation observed before speciation. In this paper, we test for congruence in the mechanisms of microevolution and macroevolution by comparing the patterns of life history divergence among three …
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 …