Iterative evolution: How a bird that went extinct came back from the dead

Why in news?
  • 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”.
  • It means the repeated evolution of similar or parallel structures from the same ancestor but at different times.
More in news
  • White-throated Rail:
    (1) The white-throated rail is a chicken-sized bird, indigenous to Madagascar.
    (2) Migrating to Aldabra, the rails evolved so that they lost the ability to fly.
  • Iterative Evolution:
    (1) There are many examples of iterative evolution in the fossil record, spanning a wide range of groups.
    (2) 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.
    (3) Since there were no natural predators, the birds soon evolved to become flightless.
    (4) But about 136,000 years ago, sea levels rose and the island was completely submerged and wiped them out.
    (5) 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.
Source
Indian express.




Posted by Jawwad Kazi on 24th May 2019
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