Ring species

[[File:Ring species seagull.svg|thumb|300px|right|The ''Larus'' gulls interbreed in a ring around the Arctic (1. Larus argentatus argentatus 2. Larus fuscus sensu stricto 3. Larus fuscus heuglini 4. Larus argentatus birulai 5. Larus argentatus vegae 6. Larus argentatus smithsonianus 7. Larus argentatus argenteus)]]

'''Ring species''' are a midpoint in the process of speciation.  It happens when a species has split into several populations, some of which cannot interbreed, but some of which can breed with two or more populations that cannot breed with each other.  Or A can breed with B, B can breed with C, but A cannot breed with C.

The idea of a ring species is not without criticism.<ref>[https://whyevolutionistrue.wordpress.com/2014/07/16/there-are-no-ring-species/ There are no ring species]</ref><ref>[https://onlinelibrary.wiley.com/doi/full/10.1111/evo.13162 Digest: Why are there no ring species?*]</ref> However, arguments against "ring species" are usually based around the loose concepts used to describe a ring species versus a more modern understanding of genetics.  Generally, disputing the idea of ring species does not seek to disprove evolution, but is rather meant to criticize the idea of a ring species as overly simplistic.<ref>[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3612659/ Evolution and stability of ring species]</ref>

==''Larus'' gulls==

The standard example of ring species is the circumpolar species "ring" of gulls of genus ''Larus''. The range of these gulls forms a ring around the North Pole; there are seven populations and each population can breed with the previous and next, but the first and last cannot interbreed. This example is actually far more complicated, as again is typical in the real world - there are several other taxonomically unclear examples which belong in the same superspecies complex, such as ''L. michahellis'', ''L. hyperboreus'' and ''L. cachinnans''.

==''Ensanita'' salamanders==

Another popular example is a salamander common to and widespread across the North American west.  Ensanita Salamanders have exhibited ring species traits.<ref>[https://evolution.berkeley.edu/evolibrary/article/0_0_0/devitt_02 Discovering a Ring Species]. Understanding Evolution at berkeley.edu.</ref> Around the Cental Valley in California, it has been observed that several salamanders exhibit identical traits that imply a common speciation, while also exhibiting clear differences in reproductive traits.  The nearly identical taxonomy/habitat of these salamanders suggests the success of the species is equally viable from any side of the valley to the other. The idea is that the salamander at the north end of the valley was fit for the region, so much so that the salamanders' offspring were forced to travel farther south to compete, along both east and west sides of a valley. As the salamander population spread farther south, mutations and variations naturally occurred, but were driven mostly by reproduction.<ref>[https://bmcevolbiol.biomedcentral.com/articles/10.1186/1471-2148-11-245 Asymmetric reproductive isolation between terminal forms of the salamander ring species Ensatina eschscholtzii revealed by fine-scale genetic analysis of a hybrid zone]. BMC Evolutionary Biology volume 11, Article number: 245 (2011)</ref> Each salamander could interbreed with its closest relatives,  but when the off-shoots of the species met again on the southern side of the valley, interbreeding could not occur. As each southern variation has a northern ancestor variation with which it can still interbreed, but not an eastern or western counterpart, this implies a common local northern ancestor.<ref>[http://www.actionbioscience.org/evolution/irwin.html Unusual Demonstration of Speciation]</ref>

==With respect to design==

Ring species constitute strong evidence that evolution does indeed happen, at least such a thing would be predicted by evolution and is extremely strongly supportive of the [[theory]].  If a designer or [[God]] made all the species as they are, any two members of the same species of opposite genders should be able to reproduce. Such a system could be designed "intentionally", but only as much that the designer isn't very smart. As it stands, the geographic spread and existence of ring species is [[Occam's Razor|most simply]] explained by the evolutionary process. Ring species like the ''larus'' gulls described above, the Greenish warblers<ref>"[http://www.zoology.ubc.ca/~irwin/greenishwarblers.html The greenish warbler ring species]". ''Department of Zoology, University of Colombia'' (website). Retrieved 22 December 2018.</ref> and Green Warblers<ref>"[http://avibase.bsc-eoc.org/species.jsp?avibaseid=3542C46BC98FB367 ''Seicercus nitidus'' (Green Leaf-Warbler)]". ''Avibase'' (website). Retrieved 22 December 2018.</ref> (now considered a fully separate species resulting from isolation) in Asia, and to a lesser extent the ensatina salamander<ref>"[http://evolution.berkeley.edu/evolibrary/article/0_0_0/devitt_02 Ring Species: Unusual Demonstrations of Speciation]". ''Understanding Evolution'' (website). Retrieved 22 December 2018.</ref> in the United States, with subspecies that can interbreed between neighboring populations but not between more distant ones or at the ends of their geographical rings, present a particularly intractable problem for [[creationist]] [[pseudoscience]] because they prevent the core unit of creationist taxonomy, the perfectly interfertile [[baraminology|monobaramin]] (single created kind), from being defined in a way that isn't [[Empiricism|empirically]] wrong. [[Answers in Genesis]] thus predictably has nothing to say on the subject, though [[Creation Ministries International]] attempts to address the problem via creationist [[PRATT]]s about [[information theory]] as applied to DNA,<ref>"[http://creation.com/birds-of-a-feather-don-t-breed-together Birds of a feather don’t breed together]". Carl Wieland. ''Creation Ministries Interational'' (website). Retrieved 22 December 2018.</ref> and [[CreationWiki]] responds by [[moving the goalposts]], relaxing the definition of a created kind to "animals that share a common ancestor",<ref>"[https://web.archive.org/web/20150417015020/http://creationwiki.org/Ring_species Ring species]". ''CreationWiki''.</ref> and then promptly trips over itself as it scrambles to repeat the mantra that [[evolutionist]]s' belief in common ancestry across these kinds is an "assumption".

==External links==
*{{wpa|Ring species}}

==References==
{{reflist|2|80%}}
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[[Category:Evolution]]
[[Category:Biology]]

Categories: Evolution, Biology