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Integration Without Unification: An Argument For Pluralism In The Biological Sciences, Sandra D. Mitchell, Michael R. Dietrich Dec 2006

Integration Without Unification: An Argument For Pluralism In The Biological Sciences, Sandra D. Mitchell, Michael R. Dietrich

Dartmouth Scholarship

In this article, we consider the tension between unification and pluralism in biological theory. We begin with a consideration of historical efforts to establish a unified understanding of evolution in the neo‐Darwinian synthesis. The fragmentation of the evolutionary synthesis by molecular evolution suggests the limitations of the general unificationist ideal for biology but not necessarily for integrating explanations. In the second half of this article, we defend a specific variety of pluralism that allows for the integration required for explanations of complex phenomena without unification on a large scale.


A Subset Of Arabidopsis Ap2 Transcription Factors Mediates Cytokinin Responses In Concert With A Two-Component Pathway, Aaron M. Rashotte, Michael G. Mason, Claire E. Hutchison, Fernando J. Ferreira, G. Eric Schaller, Joseph J. Kieber Jul 2006

A Subset Of Arabidopsis Ap2 Transcription Factors Mediates Cytokinin Responses In Concert With A Two-Component Pathway, Aaron M. Rashotte, Michael G. Mason, Claire E. Hutchison, Fernando J. Ferreira, G. Eric Schaller, Joseph J. Kieber

Dartmouth Scholarship

The plant hormone cytokinin regulates numerous growth and developmental processes. A signal transduction pathway for cytokinin has been elucidated that is similar to bacterial two-component phosphorelays. In Arabidopsis, this pathway is comprised of receptors that are similar to sensor histidine kinases, histidine-containing phosphotransfer proteins, and response regulators (ARRs). There are two classes of response regulators, the type-A ARRs, which act as negative regulators of cytokinin responses, and the type-B ARRs, which are transcription factors that play a positive role in mediating cytokinin-regulated gene expression. Here we show that several closely related members of the Arabidopsis AP2 gene family of …


Phylogeographic Analyses Of Obligate And Facultative Cave Crayfish Species On The Cumberland Plateau Of The Southern Appalachians, Jennifer Elizabeth Buhay Jul 2006

Phylogeographic Analyses Of Obligate And Facultative Cave Crayfish Species On The Cumberland Plateau Of The Southern Appalachians, Jennifer Elizabeth Buhay

Theses and Dissertations

Cave systems and their unique biota are widely viewed as highly endangered, yet very little is known about basic life history, ecology, distributions, habitat requirements, and evolutionary relationships of subterranean species. The crux of the problem in cave studies is the assumption that traditionally defined morpho-species represent distinct evolutionary lineages. Convergence is exhibited in the morphologies of many animal groups, vertebrate and invertebrate, which leads to confusion in diagnosing species' boundaries, geographic distributions, gene flow routes, and imperilment. This dissertation research includes phylogeographic analyses of freshwater cave-dwelling crayfishes in the Southern Appalachians, a global hotspot of subterranean biodiversity. By examining …


Invasion Genetics Of The Blue Catfish (Ictalurus Furcatus) Range Expansion Into Large River Ecosystems Of The Chesapeake Bay Watershed, Colleen Beth Higgins Jan 2006

Invasion Genetics Of The Blue Catfish (Ictalurus Furcatus) Range Expansion Into Large River Ecosystems Of The Chesapeake Bay Watershed, Colleen Beth Higgins

Theses and Dissertations

The blue catfish, Ictalurus furcatus (Ictaluridae), is ranked among the most invasive, nonnative species of concern in the Chesapeake Bay watershed. This species, intentionally introduced to three major tributaries and a number of impoundments between 1974 and 1989 for sport fishing, has spread into three additional tributaries. Using samples from the introduced tributary populations as a baseline, we evaluated microsatellite genetic variation in light of demographic and ecological data to elucidate the potential sources of the invasive I. furcatus populations. In general, the populations surveyed in the Chesapeake Bay watershed were considerably more inbred (F ranged from 0.03 - 0.27) …