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Geographic Groupings (geographic + grouping)

Distribution by Scientific Domains

Life Sciences	75%

Selected Abstracts

Latitudinal variation in cranial dimorphism in Macaca fascicularis

AMERICAN JOURNAL OF PRIMATOLOGY, Issue 2 2010
Michael A. Schillaci
Abstract This study examines latitudinal and insular variation in the expression of sexual dimorphism in cranial length in three geographical groupings of Macaca fascicularis. In addition, the relationship between cranial length dimorphism (CLD) and sex-specific size is examined. The results of the study identified a significant relationship between CLD and latitude for only one of the three geographic groupings. Sex-specific relationships between cranial length and CLD were detected. The pattern of these relationships varied by geographic grouping. This study is important because it demonstrates that despite very similar levels of CLD in a single primate species, there exists important geographic variability in the correlates of that dimorphism. I suggest that geographically varying ecological factors may influence sex-specific natural selection and the intensity of CLD in M. fascicularis. Gaining a better understanding of this geographical variability will require that future research examines morphological variation, including CLD, within its corresponding ecological and social contexts. Such research should be comparative, and incorporate multiple geographically separated populations with disparate environmental settings. Am. J. Primatol. 72:152,160, 2010. © 2009 Wiley-Liss, Inc. [source]

Spatial grouping of United States climate stations using a hybrid clustering approach

INTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 7 2001
Arthur T. DeGaetano
Abstract The development of a hybrid clustering technique based on the geographic proximity of observing stations and some application-driven measure of statistical similarity (in this case rank correlation) is described. The procedure is then applied to temperature and precipitation data from the United States (US) Historical Climatology Network. The resulting station groups provide some insight into the number of observation stations that are necessary to monitor adequately the climate of the US. Based on temperature data alone, a 287-station subset of the original 1145 sites would be adequate to account for 80% of the spatial variability in seasonal temperature across the US. Geographically the distribution of these stations would be relatively sparse in the centre of the country with higher station density along the East Coast and from the Rocky Mountains to the West Coast. Generally, the temperature clusters match the existing US climate divisions to some extent. To monitor adequately the spatial variability of precipitation, a network of similar size could be used. However, such a network would only account for 65% of the spatial variability in precipitation. In this case, fairly uniform station density is indicated across the country with the highest station density in Florida and the Dakotas. A similar number of stations, but with slightly different geographic groupings would be adequate to monitor precipitation and temperature simultaneously. Copyright © 2001 Royal Meteorological Society [source]

Latitudinal variation in cranial dimorphism in Macaca fascicularis

Deep, hierarchical divergence of mitochondrial DNA in Amplirhagada land snails (Gastropoda: Camaenidae) from the Bonaparte Archipelago, Western Australia

BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2010
MICHAEL S. JOHNSON
Continental islands have experienced cycles of isolation and connection. Although complex genetic patterns have been described for mainland species affected by glacial cycles of isolation, island biotas have received little attention. We examined mitochondrial DNA in Amplirhagada land snails from 16 islands and two adjacent mainland areas of the Bonaparte Archipelago, in the Kimberley region of northern Western Australia. Four major clades, with sequence divergence of 16,27% in the 16S ribosomal RNA gene, correspond to the major geographic groupings, separated by 10,160 km. Distinct lineages also characterize islands that are only a few kilometres apart. The large differences indicate that the lineages are much older than the islands themselves, and show no evidence of geologically recent connection. Three of the major clades match the morphological description of Amplirhagada alta. Either this named species comprises several morphologically cryptic species, or it is a single, genetically very diverse species, distributed over much of the Bonaparte Archipelago. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100, 141,153. [source]