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731.
Sex linkage among genes controlling sexually selected traits 总被引:8,自引:0,他引:8
Klaus Reinhold 《Behavioral ecology and sociobiology》1998,44(1):1-7
Using literature data on reciprocal crosses I estimated the influence of sex-chromosomal genes on morphological and behavioral
traits. To determine a special role of the sex chromosomes for sexually selected traits, I compared the estimated influence
of X-chromosomal genes on sexually selected traits with their estimated influence on traits not under sexual selection. About
one-third of the phenotypic variation in sexually selected traits is caused by X-chromosomal genes. There was, in contrast,
no significant influence of X-chromosomal genes on traits that were classified as not sexually selected. Sexually selected
traits thus seem to be influenced significantly more by X-chromosomal genes than traits not under sexual selection. Though
this differential influence of X-chromosomal genes cannot readily be explained with current theoretical knowledge, it may
shed some light on X-linked hybrid sterility and on the discussion between arbitrary and good-gene models for the evolution
of female choice.
Received: 30 January 1998 / Accepted after revision: 20 June 1998 相似文献
732.
733.
Ilg C Dziock F Foeckler F Follner K Gerisch M Glaeser J Rink A Schanowski A Scholz M Deichner O Henle K 《Ecology》2008,89(9):2392-2398
Extreme summertime flood events are expected to become more frequent in European rivers due to climate change. In temperate areas, where winter floods are common, extreme floods occurring in summer, a period of high physiological activity, may seriously impact floodplain ecosystems. Here we report on the effects of the 2002 extreme summer flood on flora and fauna of the riverine grasslands of the Middle Elbe (Germany), comparing pre- and post-flooding data collected by identical methods. Plants, mollusks, and carabid beetles differed considerably in their response in terms of abundance and diversity. Plants and mollusks, displaying morphological and behavioral adaptations to flooding, showed higher survival rates than the carabid beetles, the adaptation strategies of which were mainly linked to life history. Our results illustrate the complexity of responses of floodplain organisms to extreme flood events. They demonstrate that the efficiency of resistance and resilience strategies is widely dependent on the mode of adaptation. 相似文献
734.
Bee-pollinated plants are frequently dichogamous: e.g. each flower has a discernable male and female phase, with only the
male phase offering a pollen reward. Pollen-collecting bees should therefore discriminate against female-phase flowers to
maximise their rate of pollen harvest, but this behaviour would reduce plant fitness due to inferior pollination. Here, we
test the hypothesis that flowers use pollen-mimicking floral guides to prevent flower-phase discrimination. Such floral guides
resemble pollen in spectral reflection properties and are widespread among angiosperm flowers. In an array of artificial flowers,
bumblebees learned less well to discriminate between flower variants simulating different flowering phases when both flower
variants carried an additional pollen-yellow guide mark. This effect depended crucially on the pollen-yellow colour of the
guide mark and on its spatial position within the artificial flower. We suggest that floral guides evolved to inhibit flower-phase
learning in bees by exploiting the innate colour preferences of their pollinators. 相似文献
735.
Pao‐Shan Yu Chia‐Jung Chen Shiann‐Jong Chen Shu‐Chen Lin 《Journal of the American Water Resources Association》2001,37(1):151-166
ABSTRACT: A reliable forecasting model is essential in real‐time flood forecasting for reducing natural damage. Efforts to develop a real‐time forecasting model over the past two decades have been numerous. This work applies the Grey model to forecast rainfall and runoff owing to the model's relative ability to predict the future using a small amount of historical data. Such a model significantly differs from the stochastic and deterministic models developed previously. Ten historical storm events from two catchment areas in northern Taiwan are selected to calibrate and verify the model. Results in this study demonstrate that the proposed models can reasonably forecast runoff one to four hours ahead, if the Grey error prediction method is further used to update the output of the model. 相似文献
736.
Ulrich Kirschbaum Rainer Cezanne Marion Eichler Klaus Hanewald Ute Windisch 《Environmental Sciences Europe》2012,24(1):1-19
Background
In the years 1970, 1980, 1985, 1995, 2005 and 2010, lichen mapping in the towns of Wetzlar and Giessen in Hesse was performed. The aim was to show the effects of immission load. Despite the application of modified test methods during the study period, the results can still be compared directly because they could be adapted to the requirements of the guidelines of the Association of German Engineers. Even the earlier study results could be interpreted partly within the scope of the guidelines. Parallel to the lichen mapping, comparative examinations of pH on tree bark were carried out.Results
In both towns, the pH of the tree bark has been increasing continuously, presently almost reaching pre-industrial values. The increase was stronger in Wetzlar than in Giessen. In 1970, the lichen vegetation showed a complete depletion. Since then the number of species has risen significantly. This development happened faster and more intensely in Wetzlar. The comparison of the lichen vegetation between 1970 and 2010 also shows an increased existence of species that are favored by hypertrophic air contaminants. In the 2010 survey, some species considered as being promoted by global warming were found for the first time.Conclusions
The increase of the bark pH can be explained by the decreasing acid pollution, primarily SO2. This is also assumed to be the main cause for the increasing number of lichen species. An explanation for Wetzlar's advantage is that the acid pollutants had been neutralized by a local industrial emittent of lime dust. With the reduction of dust emissions in Wetzlar due to the installation of filters, the bark pH in both towns steadily converged in the reference period. An examination of pre-industrial lichen studies shows that in both towns the original state of lichen vegetation has not been restored yet. 相似文献737.
Lead (Pb) contents and partition in soils collected from eleven vegetable-growing lands in Fujian Province, China, were investigated
using a modification of the BCR (Community Bureau of Reference) sequential extraction procedure coupled with the Pb isotope
ratio technique. Pb contents in Chinese white cabbage (B. Chinensis L.) grown on the lands for this study were also measured. Results showed that Pb concentrations in fifty samples of topsoil
ranged from 456 to 21.5 mg kg−1, with each mean concentration of six sampling lands exceeding the national standard (50 mg kg−1); while Pb concentrations in edible portions of thirty-two vegetable samples ranged from 0.009 to 2.20 mg kg−1, with four sampling sites exceeding the national sanitary standard (0.2 mg kg−1). A significant correlation (r = 0.971, P < 0.01) of Pb contents in the acid-extractable fractions by BCR approach and the vegetables was observed, which indicates
that the acid-extractable Pb is useful for evaluating the metal bioavailability for plants and potential risk for human health
in soils. The determination of lead isotope ratios in different chemical forms of soils by BCR sequential extraction procedures
provides useful information on the Pb isotopic composition associated with different soil fractions (especially in the acid-extractable
fractions), and the result is helpful for the further study on controlling and reducing Pb contamination in vegetable-growing
soils. 相似文献
738.
Environmental concerns have been raised that suspended solids in turbid water adversely affect human health, and that their
removal increases in the cost of water treatment. The Yongdam dam reservoir, located in the southwestern region of Korea,
is severely affected by inflowing turbid water after storms. In this study, soil samples were collected from 37 sites in the
Yongdam upstream basin to investigate mineralogical and environmental factors associated with the turbidity potential of soils
in water environments. Turbidity potential was estimated by measuring the turbidity of soil-suspension solutions after settling
for 24 h. The mineralogy of the soils was dominated by four minerals—quartz, microcline, albite, and muscovite—with lesser
amounts of hornblende, chlorite, kaolinite, illite, and mixed layer illite. The quartz content was the most variable of the
soil mineralogy among the collected samples. Principal-components analysis (PCA) was used to examine relationships between
turbidity potential and other soil properties. The variables considered in the PCA included turbidity potential, quartz content,
albite content, mean size of soil particles, clay content, clay mineral content, zeta potential, conductivity, and pH of the
soil-suspension solution. The first two components of the PCA explained 52% of the overall variation of the selected variables.
The first component was possibly explained by physical properties such as the size of the soil particles; the second was correlated
with chemical properties of the soils, for example dissolution and extent of weathering. Closer examination of the PCA results
revealed that the quartz content of the soils was negatively correlated with their turbidity potential. A linear correlation
(r = 0.63) was obtained between measured turbidity potential and that predicted using multiple regression analysis based on
the content of clay-sized particles, clay minerals, and quartz, and the conductivity of the soil-suspension solution. 相似文献
739.
A spot test for aqueous nitrate and nitrite for controlling nitrogen removal performance in small-scale wastewater treatment facilities is proposed. In this method, NO(2)(-) ion in water samples was allowed to react with sulfanilic acid and 1-naphthol to form an anionic azo dye. The resulting colored solution was introduced onto a mini column (similar to a gas detecting tube) packed with PVC particles coated with benzyl cetyl dimethyl ammonium chloride (BCDMA) and biphenyl. The NO(2)(-)-N concentration was determined visually by measuring the color band length (CBL) in the column. The CBL correlates linearly with nitrite concentration in the 4-20 mg-N l(-1) range. The concentration of nitrite+nitrate was determined after reduction to nitrite with zinc. The concentration of NO(3)(-)-N species was calculated by difference. This method was used to visually determine the concentrations of NO(2)(-)-N and (NO(2)(-)+NO(3)(-))-N in domestic wastewater samples with maximum suspended solid (SS) and chemical oxygen demand (COD) concentrations of 114 mg l(-1) and 73.9 mg l(-1), respectively. 相似文献
740.
Both the photooxidation of EDTA and the photoreduction of metal ions in metal-EDTA systems were investigated. EDTA oxidation by TiO(2) photocatalysis occurred sequentially as Cu(II)-EDTA>Cu(II)/Fe(III)-EDTA>Fe(III)-EDTA. For Cu(II)-EDTA, EDTA was completely decomposed after only 60min of irradiation. The rate of EDTA decomposition was directly correlated with the initial Cu(II) concentration in the case of a mixed Cu(II)/Fe(III)-EDTA system. The metal ions in a single metal-EDTA complex were removed following significant decomposition of EDTA. For a mixed Cu(II)/Fe(III)-EDTA system, however, no copper was removed whereas almost all of the iron was removed. The iron and copper species deposited on the TiO(2) surface were identified via EPR and XPS as mixed FeO/Fe(3)O(4) and Cu(0)/Cu(2)O, respectively. 相似文献