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Homologous Neurons And Their Locomotor Functions In Nudibranch Molluscs, James M. Newcomb
Homologous Neurons And Their Locomotor Functions In Nudibranch Molluscs, James M. Newcomb
Biology Dissertations
These studies compare neurotransmitter localization and the behavioral functions of homologous neurons in nudibranch molluscs to determine the types of changes that might underlie the evolution of species-specific behaviors. Serotonin (5-HT) immunohistochemistry in eleven nudibranch species indicated that certain groups of 5 HT-immunoreactive neurons, such as the Cerebral Serotonergic Posterior (CeSP) cluster, are present in all species. However, the locations and numbers of many other 5 HT-immunoreactive neurons were variable. Thus, particular parts of the serotonergic system have changed during the evolution of nudibranchs. To test whether the functions of homologous neurons are phylogenetically variable, comparisons were made in species …
Integration Without Unification: An Argument For Pluralism In The Biological Sciences, Sandra D. Mitchell, Michael R. Dietrich
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.
Population Divergence In Plasticity Of The Avt System And Its Association With Aggressive Behaviors In A Death Valley Pupfish, Sean C. Lema
Population Divergence In Plasticity Of The Avt System And Its Association With Aggressive Behaviors In A Death Valley Pupfish, Sean C. Lema
Biological Sciences
Behavioral differences can evolve rapidly in allopatry, but little is known about the neural bases of such changes. Allopatric populations of Amargosa pupfish (Cyprinodon nevadensis) vary in aggression and courtship behaviors in the wild. Two of these wild populations were recently found to differ in brain expression of arginine vasotocin (AVT)—a peptide hormone shown previously to modulate aggression in pupfish. These populations have been isolated for less than 4000 years, so it remained unclear whether the differences in behavior and neural AVT phenotype were evolved changes or plastic responses to ecologically dissimilar habitats. Here, I tested whether these …
Optimal Foraging: Some Theoretical Explorations, Eric Charnov, Gordon H. Orians
Optimal Foraging: Some Theoretical Explorations, Eric Charnov, Gordon H. Orians
Biology Faculty & Staff Publications
This book had its genesis in a rather disorganized and poorly conceived lecture on optimal foraging theory that one of us (GHO) gave to an advanced ecology class during the winter of 1971.The deficiencies in that treatment, combined with the obvious potential of an improved conceptualization and analysis of the problem, led to the formation of a small seminar on optimal foraging theory attended by Charles Fowler, Nolan Pearson and ourselves. This seminar, which extended over two academic quarters, produced the basic fine-grained foraging models and some hints about wider applications of the results. We both found ourselves independently stimulated …
Linking Direct And Indirect Data On Dispersal: Isolation By Slope In A Headwater Stream Salamander, Winsor H. Lowe, Gene E. Likens, Mark A. Mcpeek, Don C. Buso
Linking Direct And Indirect Data On Dispersal: Isolation By Slope In A Headwater Stream Salamander, Winsor H. Lowe, Gene E. Likens, Mark A. Mcpeek, Don C. Buso
Dartmouth Scholarship
There is growing recognition of the need to incorporate information on movement behavior in landscape-scale studies of dispersal. One way to do this is by using indirect indices of dispersal (e.g., genetic differentiation) to test predictions derived from direct data on movement behavior. Mark–recapture studies documented upstream-biased movement in the salamander Gyrinophilus porphyriticus (Plethodontidae). Based on this information, we hypothesized that gene flow in G. porphyriticus is affected by the slope of the stream. Specifically, because the energy required for upstream dispersal is positively related to slope, we predicted gene flow to be negatively related to change in elevation between …