Variety Of Levels (variety + of_level)

Distribution by Scientific Domains


Selected Abstracts


IS EVOLUTIONARY BIOLOGY STRATEGIC SCIENCE?

EVOLUTION, Issue 1 2007
Thomas R. Meagher
There is a profound need for the scientific community to be better aware of the policy context in which it operates. To address this need, Evolution has established a new Outlook feature section to include papers that explore the interface between society and evolutionary biology. This first paper in the series considers the strategic relevance of evolutionary biology. Support for scientific research in general is based on governmental or institutional expenditure that is an investment, and such investment is based on strategies designed to achieve particular outcomes, such as advance in particular areas of basic science or application. The scientific community can engage in the development of scientific strategies on a variety of levels, including workshops to explicitly develop research priorities and targeted funding initiatives to help define emerging scientific areas. Better understanding and communication of the scientific achievements of evolutionary biology, emphasizing immediate and potential societal relevance, are effective counters to challenges presented by the creationist agenda. Future papers in the Outlook feature section should assist the evolutionary biology community in achieving a better collective understanding of the societal relevance of their field. [source]


Diverse developmental mechanisms contribute to different levels of diversity in horned beetles

EVOLUTION AND DEVELOPMENT, Issue 3 2005
Armin P. Moczek
Summary An ongoing challenge to evolutionary developmental biology is to understand how developmental evolution on the level of populations and closely related species relates to macroevolutionary transformations and the origin of morphological novelties. Here we explore the developmental basis of beetle horns, a morphological novelty that exhibits remarkable diversity on a variety of levels. In this study, we examined two congeneric Onthophagus species in which males develop into alternative horned and hornless morphs and different sexes express marked sexual dimorphism. In addition, both species differ in the body region (head vs. thorax) that develops the horn. Using a comparative morphological approach we show that prepupal growth of horn primordia during late larval development, as well as reabsorption of horn primordia during the pupal stage, contribute to horn expression in adults. We also show that variable combinations of both mechanisms are employed during development to modify horn expression of different horns in the same individual, the same horn in different sexes, and different horns in different species. We then examine expression patterns of two transcription factors, Distal-less (Dll) and aristaless (al), in the context of prepupal horn growth in alternative male morphs and sexual dimorphisms in the same two species. Expression patterns are qualitatively consistent with the hypothesis that both transcription factors function in the context of horn development similar to their known roles in patterning a wide variety of arthropod appendages. Our results suggest that the origin of morphological novelties, such as beetle horns, rests, at least in part, on the redeployment of already existing developmental mechanisms, such as appendage patterning processes. Our results also suggest, however, that little to no phylogenetic distance is needed for the evolution of very different modifier mechanisms that allow for substantial modulation of trait expression at different time points during development in different species, sexes, or tissue regions of the same individual. We discuss the implications of our results for our understanding of the evolution of horned beetle diversity and the origin and diversification of morphological novelties. [source]


The Impact of Metropolitan Structure on Commute Behavior in the Netherlands: A Multilevel Approach

GROWTH AND CHANGE, Issue 3 2004
Tim Schwanen
ABSTRACT This paper documents the investigation of the impact of metropolitan structure on the commute behavior of urban residents in the Netherlands. Not only has the impact of monocentrism versus polycentrism been analyzed, but the influence of metropolitan density and size has also been considered, together with the ratio of employment to population and the growth of the population and employment. Furthermore, data are used at a variety of levels of analysis ranging from the individual worker to the metropolitan region rather than being drawn from aggregate level statistics alone. Multilevel regression modeling is applied to take account of the interdependencies among these levels of aggregation. With regard to mode choice, the results indicate that the probability of driving an auto to work is lower in employment-rich metropolitan regions, and rises as the number of jobs per resident has grown strongly. Furthermore, women in most polycentric regions are less likely to commute as an auto driver. All else being equal, commute distances and times for auto drivers are longer in most polycentric regions than in monocentric urban areas. In addition, commute time as an auto driver rises with metropolitan size, whereas commute distance depends on employment density and the growth of the number of jobs per resident. The investigation shows that metropolitan structure, although significantly influencing commute patterns, explains only a small part of the variation of individuals' commute behavior. [source]


The Stability of General Foreign Language Classroom Anxiety across English and French

MODERN LANGUAGE JOURNAL, Issue 3 2003
M´ximo Rodríguez
The present study examined the stability of the general foreign language classroom anxiety construct across English and French. Preservice teachers from two western universities in Venezuela, who were majoring simultaneously in these two foreign languages, participated in the study. The students represented a variety of levels within each language. They completed two Spanish versions (one for each language) of the Foreign Language Classroom Anxiety Scale (FLCAS; Horwitz, Horwitz, & Cope, 1986). Separate analyses were performed on the full sample and on a restricted sample that included only those students who were at the same level in both languages. The results supported the indirect findings reported by Saito, Horwitz, and Garza (1999) while providing direct evidence suggesting the stability of the construct across English and French. Evidence obtained for overall, within-institution, and within-level comparisons. Furthermore, analysis of psychometric technical aspects of the FLCAS indicated that the scale exhibited high reliability but moderate construct validity. [source]


Evolutionary biology and practical conservation: bridging a widening gap

MOLECULAR ECOLOGY, Issue 1 2008
GEORGINA M. MACE
Abstract At the ecosystem, species and population level, available measures suggest that average rates of loss of populations and habitats are now around 1% per year and seem likely to increase in the future. Habitat conversion continues in most parts of the world, especially in areas of high species richness, and novel threats, especially climate change, will pose new challenges. With this pressure, maintaining evolutionary processes in natural populations will be critical to longer term persistence, and will often require specific planning relevant to the context. However, in many areas of policy and practice, urgent actions tend to focus on pattern-based analyses and considerations of evolutionary and ecological processes are neglected. At a variety of levels, from setting goals to implementing conservation management at the site or species level, there are simple adjustments that can be made. Improved methods for integrating the work of scientists and policymakers is recommended, from the beginning to end of the planning process. [source]


Evaluation of software for introducing protein structure

BIOCHEMISTRY AND MOLECULAR BIOLOGY EDUCATION, Issue 5 2010
Visualization, simulation
Abstract Communicating an understanding of the forces and factors that determine a protein's structure is an important goal of many biology and biochemistry courses at a variety of levels. Many educators use computer software that allows visualization of these complex molecules for this purpose. Although visualization is in wide use and has been associated with student learning, it is quite challenging to develop visualizations that allow students to interactively observe the effects of altered amino acid sequence on protein structure. A software simulation, the protein investigator (PI), has been developed to specifically facilitate this type of exploration. When using the PI, students enter or edit an amino acid sequence; the software then simulates its folding in two dimensions using the major forces involved in protein structure. This study explores freshman undergraduate students' use of visualization and simulation when learning about protein structure. It also evaluates some of the learning outcomes from these two approaches. Our results show that simulation leads to similar learning outcomes as visualization. Because simulation allows a more interactive exploration, a combination of the two approaches may be an effective approach to introducing the basic principles of protein structure. [source]