Darwin's finches

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Darwin's finches


Galapagos finches

(gəlä`pəgōs'), species of small perching birds, constituting the subfamily Geospizinae of the tanagertanager
, any of the small, migratory perching birds of the family Thraupidae, chiefly of the tropical New World. Only five species migrate to North America; of these the scarlet tanager (Piranga olivacea) has the widest range in the United States. It is about 7 in.
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 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 DarwinDarwin, Charles Robert,
1809–82, English naturalist, b. Shrewsbury; grandson of Erasmus Darwin and of Josiah Wedgwood. He firmly established the theory of organic evolution known as Darwinism.
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 in formulating the theory of evolutionevolution,
concept that embodies the belief that existing animals and plants developed by a process of gradual, continuous change from previously existing forms. This theory, also known as descent with modification, constitutes organic evolution.
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; they are a striking example of adaptive radiationadaptive radiation,
in biology, the evolution of an ancestral species, which was adapted to a particular way of life, into many diverse species, each adapted to a different habitat.
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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 ChordataChordata
, phylum of animals having a notochord, or dorsal stiffening rod, as the chief internal skeletal support at some stage of their development. Most chordates are vertebrates (animals with backbones), but the phylum also includes some small marine invertebrate animals.
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, subphylum Vertebrata, class Aves, order Passeriformes, family Thraupidae, subfamily Geospizinae.


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

References in periodicals archive ?
Convergent evolution of Darwin's finches caused by introgressive hybridization and selection.
Previous studies have focused on seeds and fruit as food for birds, rather than on the role of birds as dispersers; most studies of Darwin's finches (Fringillidae: Geospizinae) have focused on the biology of the finch, rather than that of its food species (Bowman 1961; Abbott et al.
Interannual and interspecific variation in intensity of the parasitic fly, Philornis downsi, in Darwin's finches.
The birds, commonly known as Darwin's finches, also possess physical traits that are highly inheritable, such as weight and bill size.
What Darwin's finches can teach us about the evolutionary origin and regulation of biodiversity.
Peter Grant, writing about Darwin's finches, argued that textbooks often oversimplified the complexities of the "evolutionary processes they illustrate, the ambiguities of the evidence, and the differences of opinion among biologists about just how these birds evolved" (1991, p.
Helping at the nest in Darwin's Finches as misdirected parental care.
The authors have observed Darwin's finches in the Galapagos Islands over 34 years, surely a record long-term field study of birds.
Seed selection and handling ability of four species of Darwin's Finches.
conirostris, and perhaps other leucistic Darwin's Finches, is explained by failure of ontogenetic melanization because of leucism, extending the "default" nestling bill color into adulthood.
But unlike the Darwin's finches, lizards on different islands have independently evolved diverse communities of these twig, canopy, and grass dwelling species - almost identical lizard species have evolved in parallel on the islands of Hispaniola, Puerto Rico, Cuba, and Jamaica.
On excursions escorted by the ship's naturalists (trained by Galapagos National Park) visitors see firsthand the unique adaptations of island fauna, such as flightless cormorants, marine iguanas, giant tortoises and Darwin's finches.