Biodiversity, Disparity and Evolvability

A key problem in conservation biology is how to measure biological diversity. Taxic diversity (the number of species in a community or in a local biota) is not necessarily the most important aspect, if what most matters is to evaluate how the loss of the different species may impact on the future of the surviving species and communities. Alternative approaches focus on functional diversity (a measure of the distribution of the species among the different 'jobs' in the ecosystem), others on morphological disparity, still others on phylogenetic diversity. There are three major reasons to prioritize the survival of species which provide the largest contributions to the overall phylogenetic diversity. First, evolutionarily isolated lineages are frequently characterized by unique traits. Second, conserving phylogenetically diverse sets of taxa is valuable because it conserves some sort of trait diversity, itself important in so far as it helps maintain ecosystem functioning, although a strict relationships between phylogenetic diversity and functional diversity cannot be taken for granted. Third, in this way we maximize the "evolutionary potential" depending on the evolvability of the survivors. This suggests an approach to conservation problems focussed on evolvability, robustness and phenotypic plasticity of developmental systems in the face of natural selection: in other terms, an approach based on evolutionary developmental biology

Biophysical interactions in tropical agroforestry systems

sequential systems, simultaneous systems Abstract. The rate and extent to which biophysical resources are captured and utilized by the components of an agroforestry system are determined by the nature and intensity of interac-tions between the components. The net effect of these interactions is often determined by the influence of the tree component on the other component(s) and/or on the overall system, and is expressed in terms of such quantifiable responses as soil fertility changes, microclimate modification, resource (water, nutrients, and light) availability and utilization, pest and disease incidence, and allelopathy. The paper reviews such manifestations of biophysical interactions in major simultaneous (e.g., hedgerow intercropping and trees on croplands) and sequential (e.g., planted tree fallows) agroforestry systems. In hedgerow intercropping (HI), the hedge/crop interactions are dominated by soil fertility improvement and competition for growth resources. Higher crop yields in HI than in sole cropping are noted mostly in inherently fertile soils in humid and subhumid tropics, and are caused by large fertility improvement relative to the effects of competition. But, yield increases are rare in semiarid tropics and infertile acid soils because fertility improvement does not offse

The Discrete Cosine Transform, a Fourier-related Method for Morphometric Analysis of Open Contours

The discrete cosine transform (DCT) is described and then tested to see whether it is a suitable Fourier-related method for morphometric analysis of open outlines. While most Fourier methods are mainly effective with closed outlines, the DCT can handle open curves too, making it useful for quantitative descriptions of a broad range of natural objects. Like other Fourier-type methods, the DCT yields informative numerical signatures; the shape serves as input for subsequent multivariate analysis, with, for example, principal component analysis (PCA). To test the DCT as a morphometric tool, a set of 32 ammonite ribs was analyzed. The ammonites, representing 16 different species belonging to nine genera, were from the Hildoceratidae, a major Lower Jurassic family with essentially falcoid s.l. ribs, whose taxonomy is based largely on their ornamentation. Species were selected to illustrate the broad spectrum of ribbing patterns from almost straight to falcate via sigmoidal or falcoid, exhibited by the NW European Hildoceratidae. The first six harmonic amplitudes computed by the DCT were processed by PCA. The first three factorial axes of the PCA accounted for 87.2% of the total variance. Projections of the specimens on the first two factorial planes provide a well structured plot of the entire morphospace, demonstrating that the DCT is a promising and effective tool for morphometry

A proposal for the Global Boundary Stratotype Section and Point (GSSP) for the base of the Pliensbachian Stage (Lower Jurassic)

Wine Haven, a coastal exposure at Robin Hood's Bay (North Yorkshire, UK), fulfils the criteria indicated in the Guidelines of the International Commission on Stratigraphy (ICS) (Remane et al. 1996) for definition as the Global Stratotype Section and Point (GSSP) for the base of the Pliensbachian Stage (Early Jurassic): 1) The succession of about 30m comprises pale grey and buff-coloured sandy mudstones which very gradually pass upward into silty dark grey shales. This marine sequence was deposited during an overall transgression and is relatively expanded stratigraphically. 2) There is absence of unconformities in the Sinemurian-Pliensbachian interval and the exposure is continuous. 3) Ammonites are abundant and well preserved, enabling detailed correlations to be made (see Dommergues and Meister 1992). The ammonite fauna below the boundary interval allows recognition of the Leptechioceras gr. meigeini, Paltechioceras aureolum and Paltechioceras tardecrescens horizons of latest Sinemurian age and, above the boundary, the Bifericeras donovani and Apoderoceras gr. aculeatum horizons of earliest Pliensbachian age. A suitable level for the boundary is defined with the association of the Bifericeras donovani DOMMERGUES and MEISTER and Apoderoceras sp. at the base of bed 73b. Other fossils (palynomorphs, foraminiferas, ostracods, etc) give no precise biostratigraphic information or have not been studied. 4) Complementary results are: a) Strontium-isotope stratigraphy, based on analysis of belemnites which yield a calcite 87Sr/86Sr ratio for the suggested boundary level of 0.707425 and supports an interpretation of continuous sedimentation. b) Belemnite oxygen-isotope data indicate a significant temperature drop (-5 °C) across the boundary at this locality. c) A Transgressive Systems Tract (TST) initiated in the Aplanatum Subzone (uppermost Sinemurian) continues into the Lowermost Pliensbachian (Taylori Subzone): it forms part of a transgressive facies cycle sensu Graciansky et al. 5) The section is well exposed in the cliff and on the foreshore and access is straight forward. 6) Structural complexity and metamorphism are negligible. 7) The locality is the part of a Site of Special Scientific Interest (SSSI), and thereby under statutory protection

Both antenatal and postnatal inflammation contribute information about the risk of brain damage in extremely preterm newborns

Background: Preterm newborns exposed to intrauterine inflammation are at increased risk of neurodevelopmental disorders. We hypothesized that adverse outcomes are more strongly associated with a combination of antenatal and postnatal inflammation than with either of them alone. Methods: We defined antenatal inflammation as histologic inflammation in the placenta. We measured the concentrations of seven inflammation-related proteins in blood obtained on postnatal days 1, 7, and 14 from 763 infants born before 28 weeks of gestation. We defined postnatal inflammation as a protein concentration in the highest quartile on at least 2 days. We used logistic regression models to evaluate the contribution of antenatal and postnatal inflammation to the risk of neurodevelopmental disorders. Results: The risk of white matter damage was increased when placental inflammation was followed by sustained elevation of CRP or ICAM-1. We found the same for spastic cerebral palsy when placental inflammation was followed by elevation of TNF-α or IL-8. The presence of both placental inflammation and elevated levels of IL-6, TNF-α, or ICAM-1 was associated with an increased risk for microcephaly. Conclusion: Compared to a single hit, two inflammatory hits are associated with stronger risk for abnormal cranial ultrasound, spastic cerebral palsy, and microcephaly at 2 years