The Voyage that shook the World - Galápagos finches

The above video clip is an extract from the DVD The Voyage that shook the World - The Galápagos finches are commonly cited as a prime example of evolution; indeed, the example that allegedly inspired Darwin's theory. Darwin postulated that all the varieties of finches, with varying beaks suited for their different food sources, were all descended from the same sort of finch and the different varieties of finch arose over time. This was actually reasonable. Suppose some finches with the genetic information for a wide variety of beaks came to the islands in a storm, and that some were on an island where the main food source was hard seeds. Birds with genes for thick and strong beaks could cope with them better, so would be better fed, and thus more likely to leave offspring. But birds on an island with few seeds but lots of grubs would do better with longer and thinner beaks, so they could poke deeper into the ground and pull out their prey. This is indeed an example of adaptation and natural selection. But note that it actually removes genes from the populations—on seed-rich islands with few grubs, information for long, slender beaks would likely be lost; while the information for thick, strong beaks would be lost on grub-rich (seed-poor) islands. So this change is in the opposite direction from goo-to-you evolution, which requires new genes with new information. It can hardly be over-emphasized: natural selection is not evolution.

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