Life Sciences Commons^™

The Influence Of Plant Population Spatial Arrangement On Individual Plant Yield, John L. Lindquist, D. Rhode, K. J. Puettmann, B. D. Maxwell

John L. Lindquist

Two greenhouse experiments were conducted to evaluate the performance of individual oat (Avena sativa) target plants as influenced by neighbor oat plants with different spatial arrangements. Crop spatial arrangement was separated into three com- ponents: (I) population density, (2) distance between plants (distance dispersion, DD), and (3) angular arrangement of plants about one another (angular dispersion, AD). Distance dispersion was quantified using a weighted mean distance from a target individual to its neighbors. Angular dispersion of neighbors around the target was quantified using a measure of circular variance. DD and AD were combined to create a dispersion index (DI). At …

A Tale Of Two Haplotypes: The Eda2r/Ar Intergenic Region Is The Most Divergent Genomic Segment Between Africans And East Asians In The Human Genome, Amanda M. Casto, Brenna M. Henn, Jeffery M. Kidd, Carlos D. Bustamante, Marcus W. Feldman

Human Biology Open Access Pre-Prints

Single nucleotide polymorphisms (SNPs) with large allele frequency differences between human populations are relatively rare. The longest run of SNPs with an allele frequency difference of one between the Yoruba of Nigeria and the Han Chinese is found on the long arm of the X chromosome in the intergenic region separating the EDA2R and AR genes. It has been proposed that the unusual allele frequency distributions of these SNPs are the result of a selective sweep affecting African populations that occurred after the Out-of-Africa migration. To investigate the evolutionary history of the EDA2R/AR intergenic region, we characterized the haplotype structure …

Observations Of Oviposition Behavior Among North American Tiger Beetle (Coleoptera: Carabidae: Cicindelinae) Species And Notes On Mass Rearing, Mathew L. Brust, C. Barry Knisley, Stephen M. Spomer, Kentaro Miwa

University of Nebraska State Museum: Entomology Papers

Although the larvae of a large number of North American tiger beetle species have been described, little information exists on the oviposition behavior of female tiger beetles at the species level. In this study, we found that the oviposition behavior varied widely among species, with some species utilizing more than one method. We found that, contrary to many references, several tiger beetle species did not oviposit from above the soil surface by inserting the ovipositor into the soil. Instead, several species oviposited by tunneling over 20 mm below the soil surface. In addition, we outline recently used successful protocols for …

Alfred Russel Wallace & The Notion Of Final Causes In Evolution, Charles H. Smith

Faculty/Staff Personal Papers

The methodology of Empiricism, with its emphasis on linking efficient causes to specific effects, has now dominated science for over three hundred years, and to productive end. Another of the other original Aristotelian concepts of causation, however, the notion of “final causes,” has largely been ignored by the scientific community – perhaps because it seems to necessitate teleology, or even direct interventions (“first causes”) from outside of the realm of natural process.

The most famous example of the operation of final causes comes down from ancient times. The sculptor is described as imagining what his completed form will look like, …

Testing The Role Of Male-Male Competition In The Evolution Of Sexual Dimorphism: A Comparison Between Two Species Of Porcelain Crabs, J. Antonio Baeza, Cynthia M. Asorey

Biological Sciences Faculty Publications

Theory predicts marked sexual dimorphism in terms of body size and body structures used as weapons (e.g. chelipeds) in gonochoric species with intense male sexual competition for receptive females and reduced or no sexual dimorphism in species where competition among males is trivial. We tested this hypothesis using a pair of closely-related species of symbiotic porcelain crabs as a model. In one species that inhabits sea anemones solitarily, competition among males for receptive females is unimportant. In a second species that dwells as dense aggregations on sea urchins, malemale competition for sexual partners is recurrent. We expected considerable sexual dimorphism …