| A classical example of allopatric speciation is the ring of
races/subspecies around the North Pole. The British Herring gull (A) has
his breeding grounds in Great Britain. Some of these birds have crossed the
ocean to America, which gave rise to the American Herring gull (B). The next
populations are those of the Vega Herring gull (C) in Eastern Siberia and
the Siberian lesser black-backed gull in Western Siberia. Next comes the
Scandinavian black-backed gull (D). Some of these black-backed gulls have
settled down in Great Britain and they became the ancestors of the Lesser
black-backed gull (E). On the Isle of Skokholm in Wales live nowadays the
British Herring gull as well as the Lesser black-backed gull in the same
area without interbreeding. They are two different species. |
This map shows the territories of the different races or subspecies of
this story.
However .....
DNA research on these birds has recently revealed that the story is not true!
It appeared not to be a simple ring of races and subspecies: the pattern
of ancestry is much more complicated. The example will therefore disappear
little by little from the textbooks. But the concept of ring species stays
valid because there are other rings which have been proven with DNA. The
best- known are the ring of the greenish warbler in Tibet and the ring of
salamanders in the Unites States.
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more?
Ring species
Salamander
ring species |
