Species level phylogenetic hypotheses can be used to explore patterns of divergence and speciation. In the tropics, speciation is commonly attributed to either vicariance, perhaps within climate-induced forest refugia, or ecological speciation caused by niche adaptation. Mimetic butterflies have been used to identify forest refugia as well as in studies of ecological speciation, so they are ide...

a simple, rapid and sensitive solvent assisted-dispersive solid phase extraction method was developed for the extraction of iron(ii) prior to its spectrophotometric determination. the fe(ii) reacted with 2,4,6-tris(2-pyridyl)-1,3,5-triazine, neutralized with sodium dodecyl sulfate and extracted onto the fine particles of benzophenone which were formed upon rapid injection of a mixture of benzop...

Mitochondrial Cytochrome Oxidase Subunit I DNA sequences are a good discriminative marker for phylogenetic studies in crustaceans and especially in amphipoda. In the present study, molecular and morphological data were analyzed to test whether Gammarus lobifer authority and Gammarus balutchi authority which one or two geographically separated but morphologically similar species. The analyses pr...

The present day status of elemental speciation is largely based on the use of hyphenated techniques in particular in the combination of various types of chromatography with inductively coupled plasma mass spectrometry. The present status of environmental speciation with the hyphenated techniques is reviewed. There is a growing need for more comprehensive approaches including the direct analysis...

Evolutionary biologists have sought a correlation between rates of genetic evolution and speciation ever since Mayr (1) proposed his founder-effect model of speciation; indeed this link formed the basis of the theory of punctuated equilibrium. Yet to date few correlations between net rates of speciation (speciation minus extinction) and genetic change have been demonstrated (2, 3), nor has an e...

Although competitive speciation is more and more regarded as a plausible mechanism for sympatric speciation of non-parasite species, virtually no empirical or theoretical study has considered this evolutionary process to explain intra-host diversification of parasites. We expanded the theory of competitive speciation to parasite species looking at the effect of macro-parasite life history on th...

The genic view of the process of speciation is based on the notion that species isolation may be achieved by a modest number of genes. Although great strides have been made to characterize 'speciation genes' in some groups of animals, little is known about the nature of genic barriers to gene flow in plants. We review recent progress in the characterization of genic species barriers in plants w...

The high frequency of speciation events associated with species Xocks (i.e., radiations of closely related species) provides invaluable insight into the speciation process. Investigations of the speciation process in the marine environment are rare, and therefore, the genetic analysis of the rockWsh genus Sebastes, considered an ancient marine species Xock, provides an opportunity to investigat...

Species are fundamental units of comparison in biology. The newly discovered importance and ubiquity of host-associated microorganisms are now stimulating work on the roles that microbes can play in animal speciation. We previously synthesized the literature and advanced concepts of speciation by symbiosis with notable attention to hybrid sterility and lethality. Here, we review recent studies ...