Evidence for sympatric speciation

Geographical barriers can cause populations to differentiate genetically and morphologically, but real world evidence of sympatric speciation - the emergence of two species from a single, mixed-parent population, without the aid of geography - has proved elusive. Two studies published this week in Nature claim to provide solid examples.One study found that two species of palm tree endemic to Lord Howe Island in western Australia met the criteria for sympatric speciation - specifically, they were sister species that diverged long after the island was formed, 6.9 million years ago. "We've ticked all the boxes," co-author William Baker at the Royal Botanic Gardens, Kew, UK, told The Scientist.Previous research has attempted to provide examples of sympatric speciation, but appear less than watertight. To convincingly demonstrate sympatric speciation, the species must be true sister taxa that are reproductively isolated while occupying overlapping ranges. However, there must also be little opportunity...