Greenish Warblers are Not Ring Species

Greenish Warbler

Source: Johann Naumann

The Ring Species Concept was first suggested in 1905 and then later formalized in the 1940’s. It suggested that the evolutionary process of speciation could be seen across geographic space by showing distant variations of the same animal could not interbreed. In 1938, Claud Ticehurst suggested that the Greenish Warbler populations surrounding the Tibetan Plateau might qualify as a Ring Species. With further study, it was found that the distant variations do interbreed with fertile offspring and DNA analysis shows genetic isolation rather than the gene flow which is expected in a Ring Species. Therefore, the Greenish Warblers do not qualify as a Ring Species.

Greenish Warbler Varieties

The Greenish Warblers of Asia, known taxonomically as Phylloscopus trochiloides, are small insect-eating songbirds which live in the forested regions of northern and central Asia. The various populations surround the high Tibetan Plateau where the two ends or the ring overlap in Siberia. There is some difference in plumage throughout the range, but of more significance is the difference in vocalization in bird songs which changes and becomes more complex as one travels north in either side of the ring.

Greenish Warbler Ring Species

Source: Unknown

Expected Appearance of Ring Species

By definition, there are several basic characteristics that must be matched by a plant or animal to qualify as a Ring Species. The three most prominent characteristics are: 1) a series of connected populations encircling a geographic barrier, 2) continuous gene flow along both branches of the ring, and 3) the end populations must be sufficiently different to prohibit interbreeding where they come together.

Actual Appearance of Phylloscopus trochiloides

Recent DNA analysis has demonstrated sharp breaks between areas which suggests isolation rather than gene flow. The two Siberian sub-species, P.t. plumbeitarsus and P.t. viridanus, have been found to hybridize in the wild resulting in fertile offspring.

Conclusion

The Green Warbler complex does not meet two of the necesary requirements for being considered a Ring Species.

Other Ring Species Articles

  • 1) The Ensatina Salamanders surrounding the Central Valley of California
  • 2) The Larus Gulls near the Arctic Circle
  • 3) The Greenish Warbler surrounding the Tibeten Plateau
  • 4) The Crimson Rosella Parrot in Australia
  • 5) The Caribbean Slipper Spurge in Central America.
  • For More Information:

  • 1) Irwin, D., Irwin, J., and Price, T. (2001) Ring Species as bridges between microevolution and Speciation. Genetica 112-113: 223-243, 2001.
  • XXXIIH. Last Updated: 08/01/2016
    Todd Elder

    Todd Elder

    Todd Elder has a deep desire to understand and experience Creation. As a Baraminologist, his current research includes developing the Katagenos Species Concept, the Natanzera Classification System, and the Floral Formula Method of determining Plant Kinds. As an author and speaker, his books and seminar materials are designed to encourage a growing relationship with the Creator.
    Todd Elder

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