Species Do Not Need To Evolve Differently To Survive, Study

Challenging Darwin's Origin of Species theory, researchers of a new study found that species living together are not forced to evolve differently in order to survive, according to an Oxford University study.

Owing to their huge diversity, ovenbirds were made the subject of this new study that looked into how differences in species evolved. According to the press statement, the fact that species difference is more profound in species living together than apart; it can be attributed to the "artefact of species being old by the time they meet."

"It's not so much a case of Darwin being wrong, as there is no shortage of evidence for competition driving divergent evolution in some very young lineages," said Dr Joe Tobias of Oxford University's Department of Zoology, who led the study in the statement. "But we found no evidence that this process explains differences across a much larger sample of species."

According to Tobais, the mechanism behind species differences evolution is linked to the way new species of animals originate by geographic separation. Through the study researchers found that most ovenbird species meet their closest relatives millions of years after separation, which gives them ample time to evolve differently.

For the study, researchers compared the beaks, legs and songs of over 90 percent of ovenbird species. Researchers were surprised to find that while some birds living together had similar beaks and legs to those species living apart, they also had similar songs. This discovery challenged previous theories that suggested bird species living apart develop different songs to avoid confusion.

"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."

Researchers of the study noted that further studies need to be conducted to better understand why these similarities exist. One theory is that it may be beneficial for two closely related species to share a similar song in order 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," concluded 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."

Findings of the study were published online in the journal Nature.