This chapter summarizes our current understanding of the ionosphere of Saturn. We give an overview of Saturn ionospheric science from the Voyager era to the present, with a focus on the wealth of new data and discoveries enabled by Cassini, including a massive increase in the number of electron density altitude profiles. We discuss recent ground-based detections of the effect of “ring rain” on ...

In order to investigate light and temperature effects on germination of different ecotypes of wild mustard  (Sinapis arvensis L.), seeds were collected from four regions: Fars, West Azarbayjan, Khouzestan and Mazandaran Provinces. Seed size and weight, difference of dormancy state among the ecotypes, seed germination in differential light and temperature conditions were studied. The results sho...

The cyanobacterium Prochlorococcus numerically dominates the photosynthetic community in the tropical and subtropical regions of the world's oceans. Six evolutionary lineages of Prochlorococcus have been described, and their distinctive physiologies and genomes indicate that these lineages are "ecotypes" and should have different oceanic distributions. Two methods recently developed to quantify...

The process of plant speciation often involves the evolution of divergent ecotypes in response to differences in soil water availability between habitats. While the same set of traits is frequently associated with xeric/mesic ecotype divergence, it is unknown whether those traits evolve independently or if they evolve in tandem as a result of genetic colocalization either by pleiotropy or genet...

Inhibition of photosynthesis and epidermal damage resulting from ultraviolet irradiation were assessed for arctic and alpine plant species. These species were taken from a latitudinal gradient of the arctic-alpine life zone from the Andes to northern Alaska, which spans a steep change in solar UV-B irradiation (280 to 320 nm). Ecotypes and species from the Arctic, where solar UV-B flux is very ...

The broadly defined species of bacterial systematics frequently contain unnamed and unrecognized populations (ecotypes) differing in physiology, genome content, and ecology. Without formal recognition of such ecotypes, it is difficult for microbial ecologists to detect replacement of one ecotype by another in the face of global warming. The ecotype simulation algorithm has proved capable of sup...

Parallel speciation can occur when traits determining reproductive isolation evolve independently in different populations that experience a similar range of environments. However, a common problem in studies of parallel evolution is to distinguish this hypothesis from an alternative one in which different ecotypes arose only once in allopatry and now share a sympatric scenario with substantial...

We describe five novel Methylophilaceae ecotypes from a single ecological niche in Lake Washington, USA, and compare them to three previously described ecotypes, in terms of their phenotype and genome sequence divergence. Two of the ecotypes appear to represent novel genera within the Methylophilaceae. Genome-based metabolic reconstruction highlights metabolic versatility of Methylophilaceae wi...

Recent research has shown the potential for nonallopatric speciation, but we lack an adequate understanding of the mechanisms of prezygotic barriers and how these evolve in the presence of gene flow. The marine snail Littorina saxatilis has distinct ecotypes in different shore microhabitats. Ecotypes hybridize in contact zones, but gene flow is impeded by assortative mating. Earlier studies hav...

Ecological sociobiology is an emerging field that aims to frame social evolution in terms of ecological adaptation. Here we explore the ecological context for evolution of quorum sensing diversity in bacteria, where social communication is limited to members of the same quorum sensing type (pherotype). We sampled isolates of Bacillus subtilis from soil on a microgeographical scale and identifie...