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Rapid Evolution in the Galápagos Islands

Research offers an exciting example of rapid evolution
© David Cook CC View Large

Scientists have long thought that new species took a very long time to emerge. This thinking has now changed dramatically. On an island in the Galápagos, researchers Rosemary and Peter Grant discovered that a hybrid union of two distinct species of finch produced descendants different from any of the island’s known species — and the speciation happened in just two generations.

Today's show brought to you by the Bobolink Foundation.

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BirdNote®

Rapid Evolution in the Galápagos Islands

Written by Bob Sundstrom
 
(Medium Ground-Finch song, https://macaulaylibrary.org/asset/82575 and Galápagos Island enviro. ambi: https://macaulaylibrary.org/asset/89585  )

This is BirdNote.

Scientists have long thought that new species took a very long time to emerge. This thinking has now changed dramatically, thanks to research done in the Galápagos—the site of Charles Darwin’s inspiration.

On the small island of Daphne Major, Rosemary and Peter Grant have studied the three species of native finches for decades. One day in 1981, they watched a newcomer arrive, a larger finch from an island a hundred miles away. Before long, the new finch mated with one of the finches already on the island.

(Medium Ground-Finch song, https://macaulaylibrary.org/asset/82575 )

No one expected it, but this hybrid union produced descendants different from any of the island’s known species. Different enough that the hybrid males’ songs didn’t attract females of the other species. And the beaks of the new finches had a unique size and shape.

Ultimately, the new line of offspring began to breed among themselves and became established on the island. Blood samples showed the new birds were genetically unique. There was now a new species of finch on the island.

The Grants had a front-row view of the emergence of a new, unique species. And it had happened in just two generations—faster than anyone had thought possible.

(Medium Ground-Finch song, https://macaulaylibrary.org/asset/82575 )

For BirdNote, I’m Mary McCann.

Today's show brought to you by the Bobolink Foundation.

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Bird sounds provided by The Macaulay Library of Natural Sounds at the Cornell Lab of Ornithology, Ithaca, New York. Recorded by Robert I. Bowman and Gregory Budney.
BirdNote’s theme music was composed and played by Nancy Rumbel and John Kessler.
Producer: John Kessler
Managing Producer: Jason Saul
Associate Producer: Ellen Blackstone
© 2018 Tune In to Nature.org   July 2018   Narrator: Mary McCann

ID# galapagos-01-2018-07-23   galapagos-01

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