Elements （vanadium and zinc） were determined in the two most abundant species of shell mollusks （Unio tigridis and Fiviparous bengalensis） and the water where they live in five stations in the Iraqi marshes. The s...Elements （vanadium and zinc） were determined in the two most abundant species of shell mollusks （Unio tigridis and Fiviparous bengalensis） and the water where they live in five stations in the Iraqi marshes. The study of concentrations elements was a target organ for aquatic environmental. Comparison between the mean concentrations of the elements in the water concentration levels of all studied elements was the highest with the mollusks. The results show that the station 5 is where the highest concentrations are found in water and in the two species. There is a significant correlation （P = 0.224） for concentrations of vanadium and P = 0.735 for zinc in two species of mollusks relative to their concentrations in surface water. All significant differences were accepted at a level of P 〈 0.05. The potential uptake of elements including V and Zn, as Viviparous bengalensi 〉 Unio tigridis, The mechanism for elements uptake determined by water for organisms confined to the contaminated areas seemed to be largely independent of species, mollusks demonstrated a significant positive relationship with water. These results have important implications for the utility of marshes biota as subjects for elements monitoring program.展开更多
Sexual selection is expected to promote speciation by fostering the evolution of sexual traits that minimize reproductive interactions among existing or incipient species. In species that compete for access to, or att...Sexual selection is expected to promote speciation by fostering the evolution of sexual traits that minimize reproductive interactions among existing or incipient species. In species that compete for access to, or attention of, females, sexual selec- tion fosters more elaborate traits in males compared to females. If these traits also minimize reproductive interactions with het- erospecifics, then species with enhanced risk of interactions between species might display greater numbers of these sexually di- morphic characters. We tested this prediction in eight families of North American birds. In particular, we evaluated whether the number of sexually dimorphic traits was positively associated with species richness at a given site or with degree of sympatry with congeners. We found no strong evidence of enhanced sexual dimorphism with increasing confamilial species richness at a given site. We also found no overall relationship between the number of sexually dimorphic traits and overlap with congeners across these eight families. However, we found patterns consistent with our prediction within Anatidae （ducks, geese and swans） and, to a lesser degree, Parulidae （New World warblers）. Our results suggest that sexually selected plumage traits in these groups potentially play a role in reproductive isolation [Current Zoology 58 （3）： 453--462, 2012].展开更多
文摘Elements （vanadium and zinc） were determined in the two most abundant species of shell mollusks （Unio tigridis and Fiviparous bengalensis） and the water where they live in five stations in the Iraqi marshes. The study of concentrations elements was a target organ for aquatic environmental. Comparison between the mean concentrations of the elements in the water concentration levels of all studied elements was the highest with the mollusks. The results show that the station 5 is where the highest concentrations are found in water and in the two species. There is a significant correlation （P = 0.224） for concentrations of vanadium and P = 0.735 for zinc in two species of mollusks relative to their concentrations in surface water. All significant differences were accepted at a level of P 〈 0.05. The potential uptake of elements including V and Zn, as Viviparous bengalensi 〉 Unio tigridis, The mechanism for elements uptake determined by water for organisms confined to the contaminated areas seemed to be largely independent of species, mollusks demonstrated a significant positive relationship with water. These results have important implications for the utility of marshes biota as subjects for elements monitoring program.
文摘Sexual selection is expected to promote speciation by fostering the evolution of sexual traits that minimize reproductive interactions among existing or incipient species. In species that compete for access to, or attention of, females, sexual selec- tion fosters more elaborate traits in males compared to females. If these traits also minimize reproductive interactions with het- erospecifics, then species with enhanced risk of interactions between species might display greater numbers of these sexually di- morphic characters. We tested this prediction in eight families of North American birds. In particular, we evaluated whether the number of sexually dimorphic traits was positively associated with species richness at a given site or with degree of sympatry with congeners. We found no strong evidence of enhanced sexual dimorphism with increasing confamilial species richness at a given site. We also found no overall relationship between the number of sexually dimorphic traits and overlap with congeners across these eight families. However, we found patterns consistent with our prediction within Anatidae （ducks, geese and swans） and, to a lesser degree, Parulidae （New World warblers）. Our results suggest that sexually selected plumage traits in these groups potentially play a role in reproductive isolation [Current Zoology 58 （3）： 453--462, 2012].
