Due to the fragmentation of biological habitats by road construction, a large population of frogs are killed by cars every year when they cross the roads to aquatic areas for spawning.
The perennial form, O. rufipogon, is reportedly photoperiod sensitive and cross-pollinated; it is aquatic and found in areas with year-round standing water, such as swamps, river beds, and marshes.
There are many examples for which overall structural similarity results from functional or environmental constraints rather than shared ancestry: webbing between digits in aquatic organisms, cross-sectional proportions of wings in flying animals, modifications of leaves in cold and/or dry environments.
We also demonstrate that the start of the period coincident with the onset of the Little Ice Age resulted in important thresholds crossed in catchment vegetation and aquatic communities.
Their strain resembles one found in mice, and direct cross-infection between landlubbing rodents and aquatic pinnipeds seems implausible.
Their strain resembles one found in mice, and direct cross-infection between land-lubbing rodents and aquatic pinnipeds seems implausible.
We used Geographic Information Systems (GIS) to map and analyze 13 stressor variables that represent risks to aquatic environment (e.g., road/stream crossing density, acid rock drainage risk, surface water withdrawals, human land use, and dam density).
The comet assay is also an indicator of genotoxicity and an effective biomarker for detecting DNA strand breaks, cross-links and alkali labile sites in aquatic organisms (Tice et al. 2000; Frenzilli et al. 2009).
Many ecologists define seasonal transitions by identifying biological threshold temperatures to be crossed [7], [8] and in the case of aquatic systems, the onset and deterioration of thermal stratification [9], [10] can be a useful seasonal indicator.
