determination of particular chemical forms of an element, rather than just the total element Metals may be speciated by oxidation state (Cr(VI) vs Cr(III), for example,) or by successively stronger extractions from a solid sample
the process by which one or more populations of a species become genetically different enough to form a new species The process often requires populations to be isolated for a long period of time
An analysis of the form in which a contaminant (such as a metal) exists in soil, which will help determine the source of the contaminant
separation of one population into two or more reproductively isolated, independent evolutionary units
Commercial silicates are complex mixtures of silicate anions of different molecular size Speciation describes the distribution of these anions The distribution depends on silica: alkali ratio and/or solids concentration
The process by which new species originate through mutations, natural selection, and evolution
The creation of a species through the splitting of one species into two or more, through descent
Formation of new and distinct species, whereby a single evolutionary line splits into two or more genetically independent ones. One of the fundamental processes of evolution, speciation may occur in many ways. Investigators formerly found evidence for speciation in the fossil record by tracing sequential changes in the structure and form of organisms. Genetic studies now show that such changes do not always accompany speciation, since many apparently identical groups are in fact reproductively isolated (i.e., they can no longer produce viable offspring through interbreeding). Polyploidy (see ploidy) is a means by which the beginnings of new species are created in just two or three generations
This is the evolution of multiple species from a single founding (ancestral) species Closely related forms are usually defined as species if there is some form of reproductive isolation see [1: peripatric speciation ]; [3: speciation]; [3: sympatric speciation]; [3: Observed Instances of Speciation]; [3: the concept of species ]; [ the species concept]; [ What is a Species, and What is Not? by ERNST MAYR]; [3: Speciation ]
n: Formation of two species from one species as a result of divergent natural selection in response to changes in environmental conditions; usually takes thousands or tens of thousands of years
{i} evolutionary development of a new species usually through the division of a single species into two separate genetically different groups (Biology)
(Biyoloji) Allopatric speciation, also known as geographic speciation, is the phenomenon where huge biological populations are physically isolated by an extrinsic barrier and evolve intrinsic (genetic) reproductive isolation, such that if the barrier breaks down, individuals of the populations can no longer interbreed. Evolutionary biologists agree that allopatry is a common way that new species arise. By contrast, the frequency of other types of speciation, such as sympatric speciation, parapatric speciation, and heteropatric speciation), is debated