How are ring species formed?

How are ring species formed?

A ring species is an alternative model to allopatric speciation, “illustrating how new species can arise through ‘circular overlap’, without interruption of gene flow through intervening populations…” However, Jerry Coyne and H. Allen Orr point out that rings species more closely model parapatric speciation.

Why is a ring species a problem for the biological species concept?

Each population can interbreed with other, nearby populations, but there are least two “end” populations which are too distantly related to each other to interbreed. However, there could still be gene flow between the ends by means of the other populations in the ring.

How does a ring species illustrate speciation in action?

How does a ring species illustrate speciation in action? Some populations of a ring species are reproductively isolated, while others can hybridize. Gene flow acts to homogenize (make more similar) the allele frequencies between different sub-populations.

What is ring species in evolution?

In biology, a ring species is a connected series of neighboring populations. While each can breed with those nearby, in the end at least two populations are no longer able to interbreed as both time and their environment has left them too distantly related, even though they are technically the same species.

What causes new species to form?

New species form by speciation, in which an ancestral population splits into two or more genetically distinct descendant populations. Speciation involves reproductive isolation of groups within the original population and accumulation of genetic differences between the two groups.

Why are California salamander ring species?

The idea is that this continuum of salamanders — called a ring species — represents the evolutionary history of the lineage, as it split into two. Ensatina has been recognized as a ring species since the 1940s, when biologist Robert C. Stebbins trooped up and down California to investigate its range.

What do ring species teach us about the ability of Clinal variation to lead to speciation?

We review proposed cases of ring species and the insights they provide into speciation. Our analysis suggests that these differences could have arisen even with gene flow, and that parallel rather than divergent ecological changes have led to divergence in sexually selected traits and subsequent speciation.

What is a ring species?

A ring species is a circular arrangement of populations with one boundary characterized by reproductive isolation, but intergradation among populations elsewhere. They form when populations disperse around a central barrier and form a secondary contact characterized by reproductive isolation.

What does the concept of ring species demonstrate give an example?

A ring species is a situation in which two populations which do not interbreed are living in the same region and connected by a geographic ring of populations that can interbreed. Famous examples of ring species are the herring and lesser black-backed gulls in northern Europe and the Ensatina salamanders of California.

What are ring species situations?

What is the ring species concept?

The Ring Species Concept is defined as a species with a series of connected populations which through time spread around a geographic barrier and where neighboring populations are able to interbreed but the distant populations that meet after the barrier are unable to interbreed. This concept has a long history.

How does gene flow occur in ring species?

In a ring species, gene flow occurs between neighbouring populations of a species, but at the ends of the “ring” , the populations don’t interbreed. The coloured bars show natural populations (colours), varying along a cline. Such variation may occur in a line (e.g. up a mountain slope) as in A, or may wrap around as in B.

What are some examples of ring species found in nature?

The following list gives examples of ring species found in nature. Some of the examples such as the Larus gull complex, the greenish warbler of Asia, and the Ensatina salamanders of America, have been disputed.

What are the disadvantages of the ring species concept?

The major downfall of the Ring Species concept is that the end populations, which by definition cannot interbreed, have been found to interbreed even in the wild, typically with fertile offspring. Therefore the species is only showing some variations (as varieties or subspecies) based on the surrounding environment.