Darwin's finches

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Darwin's finches

Darwin's finches or Galapagos finches (gəläˈpəgōsˌ), species of small perching birds, constituting the subfamily Geospizinae of the tanager family. Not related to the true finches, this group of at least fifteen species is confined to the Galápagos Islands, except for a single species found on Cocos Island, about 600 mi (960 km) northeast. Their special adaptations to various habitats were important evidence considered by Charles Darwin in formulating the theory of evolution; they are a striking example of adaptive radiation.

Geographically isolated and without competition from similar species, Darwin's finches developed distinctive anatomy (particularly beak size and shape) and behaviors, with each species exploiting a unique feeding niche. The bill is adapted in the different species for different purposes, such as crushing seeds, pecking wood, and probing flowers for nectar. The woodpecker finch, Camarhynchus pallidus or Cactospiza pallida, an insect-eater, holds twigs and cactus spines in its beak to fish out larvae in tree cavities. Darwin proposed that the Galapagos finches evolved on the islands from a single bird species from mainland South America. Modern methods of DNA (genetic) analysis have confirmed his insight. Darwin's finches are classified in several genera of the phylum Chordata, subphylum Vertebrata, class Aves, order Passeriformes, family Thraupidae, subfamily Geospizinae.


See P. Grant, Ecology and Evolution of Darwin's Finches (1986).

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References in periodicals archive ?
The researchers noted that such hybridization would have occurred many times in Darwin's finches in the past, some evolving into new species that either became extinct or evolved to become the species we know today.
Rosemary Grant, who have been documenting changes in populations of Darwin's finches for decades.
For many people, British ornithologist David Lack's studies of finches on the Galapagos Islands, culminating in his landmark 1947 book, Darwin's Finches, captured the essence of neo-Darwinism's metaphor of a tree with never-crossing, ever-diverging branches.
The cactus finch, one of 13 closely related Darwin's finches unique to the Galapagos, has a specially adapted beak, sturdy enough to open a hole in the side of the tough fruit.
He intends to smash the holiest relics of evolutionary theory, the examples used in textbooks or the popular press to such a degree that they have become "icons." He attacks in turn the origin of life's building blocks, the evolutionary tree, homology of vertebrate limbs, Haeckel's embryos, origin of birds, peppered moths, Darwin's finches, mutation, horse evolution, and apes to humans.
Examples of adaptive radiation include fruit flies (Drosophila) and honeycreepers (drepanidids) in Hawaii, iguanas (Ctenosaura) and lizards (Anolis) in the Antilles, and, of course, in tortoises (Geochelone elephantopus) (see figure 193) and in Darwin's finches the Galapagos Islands.
A genetic study has shown that Darwin's finches, which were cited as a textbook example of the evolutionary process, are continuing to evolve in their native Galapagos Islands, according to a U.S.
Fitness of 1987 cohorts of Darwin's Finches (over four years).
There he found some fourteen species of finches, today called Darwin's finches, which varied among themselves in food habits, size, and shape of bill.
This time I'll respond: My school is where I fit in, where I've evolved as an educator--kind of like Darwin's finches or Galapagos turtles.
These include Darwin's Finches of the Galapagos, such as the Large Ground Finch."