Speciation

'''Speciation''' is the [[Evolution|evolutionary]] process by which new distinct [[Species|species]] arise in [[Evolutionary System|evolutionary systems]]. A species is a reproductively isolated, independent evolutionary unit which occupies a certain [[Niche|niche]]. The biologist Orator F. Cook seems to have been the first to coin the term 'speciation' for the splitting of lineages or 'cladogenesis,' as opposed to 'anagenesis' or 'phyletic evolution' occurring within lineages. In the course of [[Evolution|evolution]], a lineage of a species can split into two or more. The branching or [[Bifurcation|bifurcation]] points in the [[Phylogenetic Tree|phylogenetic tree]] mark the speciation events, where a new species emerges. A main reason for speciation in biology is geographical and reproductive isolation.

[[Image:Speciation_modes.png|right|thumb|300px|Comparison of allopatric, peripatric, parapatric and sympatric speciation. Pictures was drawn by Ilmari Karonen and is from [http://en.wikipedia.org/wiki/File:Speciation_modes.svg Wikipedia]]]

The major cause of speciation in biological systems is geographical separation or isolation, the four major types of speciation in nature are based on the extent to which speciating populations are geographically isolated from one another: allopatric (very strong), peripatric (strong), parapatric (weak), and sympatric (zero). Allopatric speciation involves barrier formation or complete habitat fragmentation, peripatric speciation a small niche at the periphery of the system, parapatric speciation a new niche connected to the system, and sympatric speciation a new niche inside the population.

The major cause of speciation in economic systems is technological isolation or innovation. A new technology can create whole new markets and new "ecosystems".

== Links ==

* Wikipedia entry for [http://en.wikipedia.org/wiki/Speciation Speciation]

* [http://evolution.berkeley.edu/evolibrary/article/evo_44 Reproductive isolation]

* A seminal paper from John Maynard Smith on speciation, touching upon the dogma that speciation requires geographical separation [http://www.nature.com/nature/focus/maynardsmith/pdf/1962.pdf Disruptive selection, polymorphism and sympatric speciation]

[[Category:Evolutionary Principles]]