Home About us Contact
|
Home About us Contact | ||
|
|
||
Geographic Patterning (geographic + patterning)
Selected AbstractsChloroplast evidence for geographic stasis of the Australian bird-dispersed shrub Tasmannia lanceolata (Winteraceae)MOLECULAR ECOLOGY, Issue 14 2010J. R. P. WORTH Abstract Few chloroplast-based genetic studies have been undertaken for plants of mesic temperate forests in the southern hemisphere and fossil-based models have provided evidence of vegetation history only at the broadest scales in this region. This study investigates the chloroplast DNA phylogeography of Tasmannia lanceolata (Winteraceae), a fleshy-fruited, bird-dispersed shrub that is widespread in the mountains of southeastern Australia and Tasmania. Thirty haplotypes were identified after sequencing 3206 bp of chloroplast DNA in each of 244 individuals collected across the species' range. These haplotypes showed unexpectedly strong phylogeographic structuring, including a phylogeographic break within a continuous part of the species' range, with the distribution of four major clades mostly not overlapping, and geographic structuring of haplotypes within these clades. This strong geographic patterning of chloroplast DNA provided evidence for the survival of T. lanceolata in multiple putative wet forest refugia as well as evidence for additional wet forest species refugia in southeastern Australia. In western Tasmania lower haplotype diversity below the LGM tree line compared to above the LGM tree line suggests that glacial refugia at high altitudes may have been important for T. lanceolata. The level of geographic structuring in T. lanceolata is similar to gravity dispersed southern hemisphere plants such as Nothofagus and Eucalyptus. Behavioural traits of the birds transporting seed may have had a strong bearing on the limited transport of T. lanceolata seed, although factors limiting establishment, possibly including selection, may also have been important. [source] Understanding race and human variation: Why forensic anthropologists are good at identifying raceAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 1 2009Stephen Ousley Abstract American forensicanthropologists uncritically accepted the biological race concept from classic physical anthropology and applied it to methods of human identification. Why and how the biological race concept might work in forensic anthropology was contemplated by Sauer (Soc Sci Med 34 1992 107,111), who hypothesized that American forensic anthropologists are good at what they do because of a concordance between social race and skeletal morphology in American whites and blacks. However, Sauer also stressed that this concordance did not validate the classic biological race concept of physical anthropology that there are a relatively small number of discrete types of human beings. Results from Howells (Papers of the Peabody Museum of Archaeology and Ethnology 67 1973 1,259; Papers of the Peabody Museum of Archaeology and Ethnology 79 1989 1,189; Papers of the Peabody Museum of Archaeology and Ethnology 82 1995 1,108) and others using craniometric and molecular data show strong geographic patterning of human variation despite overlap in their distributions. However, Williams et al. (Curr Anthropol 46 2005 340,346) concluded that skeletal morphology cannot be used to accurately classify individuals. Williams et al. cited additional support from Lewontin (Evol Biol 6 1972 381,398), who analyzed classic genetic markers. In this study, multivariate analyses of craniometric data support Sauer's hypothesis that there are morphological differences between American whites and blacks. We also confirm significant geographic patterning in human variation but also find differences among groups within continents. As a result, if biological races are defined by uniqueness, then there are a very large number of biological races that can be defined, contradicting the classic biological race concept of physical anthropology. Further, our results show that humans can be accurately classified into geographic origin using craniometrics even though there is overlap among groups. Am J Phys Anthropol 2009. © 2009 Wiley-Liss, Inc. [source] Developing a blueprint for conservation of the endangered longleaf pine ecosystem based on centers of Coastal Plain plant endemismAPPLIED VEGETATION SCIENCE, Issue 1 2006Bruce A. Sorrie Abstract Question: Can the geographic patterning of endemic plant species inform reserve selection in a region of high endemism? Location: The Southeastern Coastal Plain of North America, focusing primarily on the imperiled longleaf pine (Pinus palustris P. Miller) ecosystem. Methods: We documented the high level of plant endemism in the region, and characterized the endemic taxa into distributional subregions. Results: A total of 1630 plant taxa are endemic to the Coastal Plain, a large proportion of which are endemic to phytogeographical subregions within the Coastal Plain, with particularly large numbers of narrow endemics occurring in the East Gulf Coastal Plain and Florida Peninsula. Conclusions: This pattern of local endemism presents challenges in conserving the full biota of the region: a reserve system focusing on few and large conservation areas has theoretical benefits for long-term management and viability, but will fail to capture many local endemics. We propose that the dispersed distribution of endemic species will require a mixture of large core reserves and smaller satellite reserves. [source] A study of the diversity and geographical variation in numbers of leg-bearing segments in centipedes (Chilopoda: Geophilomorpha) in north-western EuropeBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 4 2010STYLIANOS M. SIMAIAKIS Five species of geophilomorphs, Strigamia maritima (Leach, 1817), Geophilus flavus (De Geer, 1778), Geophilus truncorum Bergsøe and Meinert, 1866, Geophilus proximus C. L. Koch, 1847, and Pachymerium ferrugineum (C. L. Koch, 1835), from various sample sites in north-western Europe were examined for numbers of leg-bearing segments. Where data was adequate, mean segment numbers were correlated with latitudinal gradients for each species. Solely in S. maritima and some populations of P. ferrugineum did the results show a highly significant geographic pattern towards more leg-bearing segments in southern populations of both sexes. As concerns G. proximus, we presented for the first time a remarkable geographic shift towards an increased number of pairs of legs in northern populations. Contrary to the conventional geographic pattern, we found that G. flavus and G. truncorum did not exhibit a north,south increase or decrease in segment number. Although there was no general/universal evidence supporting the occurrence of a significant regression slope between mean segment number and latitude/temperature, more information shows that the overall region-to-region segment variation was highly significant in both sexes. In S. maritima and P. ferrugineum mean segment number was correlated with the north,south temperature cline. The same was not observed in G. proximus. Parthenogenesis in G. proximus, and a series of ecological characteristics such as habitat preferences, spatial distribution, and fragmented populations could explain the presence or absence of a geographic patterning of segment number variation along a latitudinal cline. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100, 899,909. [source] | ||||||||||