One big island mid-Manhattan in the South Atlantic Ocean is so isolated, it's called Inaccessible Island. On that island, and only on that island, live nearly 6,000 quilts called "Inaccessible Island Rails". But they can not fly, and the island is only a few million years old. How did the birds arrive?
A new analysis may have solved the mystery. The bird's DNA reveals that it has evolved relatively recently from some island visitor, and has lost its ability to fly from the forces of natural selection.
"It is quite spectacular that the birds with no living flight smaller than the word ended up in one of the most remote places ever," said study author Martin Stervander to Gizmodo, postdoctoral researcher of the study. University of Oregon. "It seems that the birds have arrived on the island, and since they faced a small threat from predators, there was not much to fly."
When scientists first described the bird in the 1
They proposed, before the theory of plate tectonics existed, that the bird would somehow walk towards the island over a sort of submerged earth bridge. They included it in their own genre, Atlantisia . More recent research has proposed that the bird originates from tracks in Africa.
The scientists behind the new paper have available analytical tools other than bird shapes and geography. They captured an inaccessible male rail of Island in September 2011, sampled his blood, sequenced his DNA and compared the results with those of other rails.
They inferred that the ancestor of the rail was a South American bird arrived on the island about 1.5 million years ago, and that it is more likely a member of the genus Laterallus which includes current birds such as the dot-shaped crab, the Galapagos crab and the black track from a similar appearance, according to the document published in the journal Phylogenetics and Evolution.
It makes sense. The rails are famous for flying everywhere and settling down, with 53 existing or recently extinct species appearing only on islands and 32 species that partially or partially lose their flight skills. A population of the ancestors of the Inaccessible Island rails probably flew eastward into the Atlantic and ended up on the island – which was a pretty sweet gig that no longer needed to fly.
"When the railway arrived at the Inaccessible Island, they" had all the food I wanted to get around and there was nothing to escape from, no need to fly " said Stervander, the only bird threats on Inaccessible Island are another species of bird that sometimes eats eggs and perhaps some seabirds.
It is not clear why railroad did not head to the other two islands – perhaps an attempted and failed population.  Stervander pointed out that there is more research to be done.The track data set was incomplete, so perhaps more data will show that the Bird really belongs to a separate genus.
And although the bird is living a good life, it is still considered a vulnerable species – bird populations without flight can easily collapse if humans bring with them invasive species, such as cats or mice
This document resolv There is perhaps the prettiest mystery in the Southern Atlantic Ocean. But if you're planning to visit the island (which is not an easy venture) make sure you do nothing to damage the birds.
[Molecular Phylogenetics and Evolution]