Pinzón terrestre grande (Large Ground Finch)

Pues debemos felicitarnos todos. Saludos.

Thanks, Karen, for reminding us of Charles Darwin's 205th birthday! I might add that at the same time we celebrate the 50th anniversary of the inauguration of the Charles Darwin Foundation's Research Station on Galapagos! Peter and Rosemary Grant and many other scientists are working through that station, providing the science and scientific training necessary to achieve lasting conservation of the Galapagos. For more info go to darwinfoundation.org and facebook.com/darwinfoundation!

Oops, I missed the typo - Darwin is actually only 205 years old today!

Today is Charles Darwin's 215th birthday! To mark the occasion our fun fact is about the birds that bear his name, and were so important to the development of his theory of evolution by means of natural selection – Darwin’s finches!

There are 15 species of finches on the Galapagos Islands, all evolved from a single ancestral species that colonized the islands only a few million years ago. Each species has adapted to exploit a specific niche on different island; this process, known as adaptive radiation, is ongoing. Biologists Peter and Rosemary Grant spent twenty years observing, catching weighing, measuring, and identifying hundreds of Galapagos finches on the small barren volcanic island of Daphne Major. Their research proved Darwin’s theories and also demonstrated that adaption doesn’t always happen over millennia as previous thought, but that sometimes natural selection takes place so rapidly we can watch it at work.

In their natural laboratory the Grants watched the struggle for survival among individuals in two species of Darwin's finches. They noted that the birds with the best-suited bodies and beaks for the particular environment were the ones most likely to survive to pass on their genes to the next generation. When the environment changed, different traits became more beneficial and the birds with those traits became the most successful. For instance during a severe drought in 1977, most of the vegetation on the island withered and seeds of all kinds were scarce. The small, soft seeds were quickly consumed, leaving mainly large, tough seeds that were usually ignored. This favored larger birds with deep, strong beaks suited to opening the hard seeds, and the majority of the smaller finches with less-powerful beaks perished. The Grants discovered that the offspring of the birds that survived the 1977 drought tended to be larger, with bigger beaks. So the adaptation to a changed environment led to a larger-beaked finch population in the following generations.

Of course, adaptation can go either way, and exceptionally wet weather in 1984-85 provided an abundance of small, soft seeds and fewer of the large, tough ones. The birds best adapted to eat those seeds were those with smaller beaks and consequently they were the ones that survived and produced the most offspring. Evolution had cycled back the other direction!

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Si, es Geospiza magnirostris. Muy buena la foto!