'Looking at the bigger picture, 'be different or die' doesn't appear to explain evolution,' said Dr Tobias. 'Ovenbird species use a wide variety of beaks, from long and hooked to short and straight, but these differences appear to evolve when living in isolation, suggesting that competition is not the major driving force producing species differences. Instead, it seems to have the opposite effect in promoting the evolution of similar songs.
'The reasons for this are difficult to explain and require further study, but they may have something to do with the advantages of using the same 'language' in terms of similar aggressive or territorial signals. For instance, individuals of two closely related species with similar songs may benefit because they are able to defend territories and avoid harmful territorial contests not only against rivals of their own species but those in other species coexisting in the same places and competing for similar resources.'
'The real novelty of this research is that it takes the evolutionary age of species into account,' said Dr Nathalie Seddon of Oxford University's Department of Zoology, co-author of the study. 'A first glance at our data suggests the same patterns that Darwin had expected. It is only when accounting for the fact that species vary in age, and then comparing between lineages of similar age, that the picture changes.'
'These insights are the result of a hugely collaborative venture, and a good example of standing on the shoulders of giants. It took almost a decade to compile genetic sequences and trait measuremen
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