Photo Courtesy of Contemplicity
Scientists from University of Melbourne have found that bird species with multiple plumage colour forms within in the same population, evolve into new species faster than those with only one colour form
Julian Huxley was the only scientist who linked between having more than one colour variation like the iconic red, black or yellow headed Gouldian finches and the faster evolution of new species. The new research, which is the only of its kind since 1950, has found that in three families of birds of prey, the hawks and eagles, the owls and the nightjars, the presence of multiple colour forms leads to rapid generation of new species. It also emerged that in the same three families the presence of multiple colour forms leads to rapid generation of new species.
The team focused on birds because they have a wealth of information on colour variation, as well as on species classification. They looked at five bird families with a high proportion of colour polymorphism and compared their rates of evolution with those with only one colour form.
The results of modelling evolutionary rates and using all available genetic information accumulated over a long period of time found that colour polymorphism speeds up the generation of new species. Colour polymorphic species tend to evolve into species with only one colour form (monomorphic), explaining why existing species with different colour forms are relatively young and also rare. The study found that colour polymorphic species were younger not only in the birds of prey but in the songbirds, which account for more than half of the world's bird species.
A huge family tree has been generated in this phase. Scientists are looking to test some of the explanations proposed for why colour polymorphism leads to accelerated evolution on upcoming phases.
By Nala Mahmoud