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Extinct Bird Reappears Again After 30,000 Years Through Evolution

Goldhedge

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Kind of throws the ol' monkey wrench in the machine don't it....





NatureScience
Extinct Bird Reappears Again After 30,000 Years Through Evolution
by Andrea D. Steffen
May 23, 2019

It is possible for a species to become extinct and then come back to life. How? Through a very unique form of evolution called iterative evolution. It is the repeated evolution of similar or parallel structures from the same ancestor but at different times.

This happens because a group of the species evolves at a specific location to adapt to the conditions there. However, there are still others of the original species somewhere else in the world. This means there are now two different species from one, through evolution. Then, something happens and the strand of the species that had evolved goes extinct. Thousands of years later, some more of the original species migrate back again to that location and re-evolves, bringing back to life the species that went extinct.

A perfect example of this process is an extinct species of rail (bird) that was recently discovered by British researchers from the University of Portsmouth and the Natural History Museum. The research was published in the Zoological Journal of the Linnean Society.

They found the species of rail successfully colonized an isolated atoll called Aldabra in the Indian Ocean on two occasions separated by tens of thousands of years. The first time around, the flightless bird was rendered extinct when its home island became flooded by the sea. However, after a 30,000-year gap, it reappeared through evolution.

A University of Portsmouth spokesman said:

“This is the first time that iterative evolution has been seen in rails and one of the most significant in bird records.”​
The bird, which is properly known as the white-throated rail, is indigenous to Madagascar. The rail species are known to be persistent colonizers. It was normal for these birds to migrate from Madagascar during frequent population explosions. One of those locations they would migrate to was the Aldabra Atoll.

The rail that migrated to this location evolved in a way that they lost the ability to fly because there were no predators there thus rendering flight unnecessary for survival. On both occasions – completely independently – it evolved to become flightless. To this day, the last surviving colony of the flightless rails can still be found on the island.

He explained:

“Aldabra disappeared when it was completely covered by the sea during a major inundation event around 136,000 years ago, wiping out all fauna and flora including the flightless rail. The researchers studied fossil evidence from 100,000 years ago when the sea-levels fell during the subsequent ice age and the atoll was recolonized by flightless rails.​
The researchers compared the bones of a fossilized rail from before the inundation event with bones from a rail after the inundation event. They found that the wing bone showed an advanced state of flightlessness and the ankle bones showed distinct properties that it was evolving toward flightlessness. ‘This means that one species from Madagascar gave rise to two different species of flightless rail on Aldabra in the space of a few thousand years.”​
Dr. Julian Hume, an avian paleontologist at the Natural History Museum, added:

“These unique fossils provide irrefutable evidence that a member of the rail family colonized the atoll, most likely from Madagascar, and became flightless independently on each occasion. Fossil evidence presented here is unique for rails, and epitomizes the ability of these birds to successfully colonize isolated islands and evolve flightlessness on multiple occasions.”​

Wing bones fossils of flighted (right) and flightless (left) Dryolimnas rails. Dr. Julian Hume

Co-author of the study published in the Zoological Journal of the Linnean Society, Professor David Martill – from the School of Earth and Environmental Sciences at the University of Portsmouth, concluded:

“We know of no other example in rails, or of birds in general, that demonstrates this phenomenon so evidently. ‘Only on Aldabra, which has the oldest paleontological record of any oceanic island within the Indian Ocean region, is fossil evidence available that demonstrates the effects of changing sea levels on extinction and recolonization events. Conditions were such on Aldabra, the most important being the absence of terrestrial predators and competing mammals, that a rail was able to evolve flightlessness independently on each occasion.”​
 

Buck

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:dduck::belly laugh::laughing::belly laugh::dduck:

Yep, sure it does...