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Open Access Thesis

Keywords

Notropis--Middle West--Geographical distribution; Academic theses;

Abstract

Periodic glacial cycles beginning 2.6 million years ago to 10,000 years ago forced the repeated contraction, fragmentation, and expansion of the North American biota. In the upper Mississippi River basin three very different areas characterize the topography left by glaciations and still and influence the flora and fauna: Driftless Area, Paleozoic Plateau, and Iowan Surface. The Paleozoic Plateau is located in the northern part of the upper Mississippi River basin, and it is a unique geographical region situated in an area that straddles northeast Iowa, southeastern Minnesota, southwest Wisconsin, and northwest Illinois. This region was bypassed by the last glacial maximum, the Wisconsinan approximately 30-13,000 YA. The lack of relatively recent glacial activity left very distinct geological formations intact, resulting in an area with a distinct topography. One organism that has a disjunct distribution between the northern Paleozoic Plateau and southern Ozark Plateau is the Ozark minnow, Notropis nubilus. The field of phylogeography provides a good framework to investigate the historical processes that lead to the disjunct distribution of Notropis nubulis. Analysis of genetic variation within the species, both mitochondrial DNA cytochrome b (cytb) gene sequence and microsatellite genotypes revealed three strongly supported clades: a clade from the western Ozarks, a clade from the Southern Ozarks, and a clade from the northern Ozarks and upper Mississippi river basin. Analysis of the data supported the hypothesis that the Ozark minnow was not able to survive in the Paleozoic Plateau and it migrated southward into an Ozarkian refugium during the greatest advances of ice sheets of the Pleistocene. After climate and habitat became more favorable populations expanded and migrated to habitats that more closely resemble their current ranges.

Year of Submission

2013

Degree Name

Master of Science

Department

Department of Biology

First Advisor

Peter Berendzen

Second Advisor

James W. Demastes

Third Advisor

James Walters

Comments

If you are the rightful copyright holder of this thesis and wish to have it removed from the Open Access Collection, please submit a request to scholarworks@uni.edu and include clear identification of the work, preferably with URL.

Date Original

2013

Object Description

1 PDF file (69 leaves)

Language

en

File Format

application/pdf

Included in

Biology Commons

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