From UPSC perspective, the following things are important :
Prelims level : About the specie
Mains level : What is Iterative Evolution?
Extinct bird rises again
- The white-throated rail is the only flightless bird known in the Indian Ocean area.
- New research has found that it had once gone extinct, but rose from the dead thanks to a rare process called “iterative evolution”.
Iterative Evolution of White-throated Rail
- It means the repeated evolution of similar or parallel structures from the same ancestor but at different times.
- There are many examples of iterative evolution in the fossil record, spanning a wide range of groups.
- The fossil record shows that sometime after the island formed 400,000 years ago, the white-throated rail – a bird native to Madagascar – colonized Aldabra.
- Since there were no natural predators, the birds soon evolved to become flightless.
- But about 136,000 years ago, sea levels rose and the island was completely submerged and wiped them out.
- Around 100,000 years ago, the island re-emerged when sea levels dropped due to an ice age.
- White-throated rails migrated there from Madagascar and once again, evolved to become flightless – a textbook example of iterative evolution and one of the strongest cases ever seen in birds.