Wildlife Conservation Efforts

Species in news: White-throated Rail (or Aldabra Rail)


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.
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