FYI: Darwin's Finches

Natacha Revelus
April 23, 2008
Bio. 1040

DARWIN’S FINCHES

Darwin was the first scientist to study the finches of the Galapagos Island, with that he made them famous. Darwin studied the different adaptive features and characteristics of the finches. No one finch was alike; they varied from island to island. This group of thirteen species is confined to the Galapagos Islands, except 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 (Questia Encyclopedia, 2004).
Geographically isolated and without competition from similar species, these 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, 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 species of finch from mainland South America. Modern methods of DNA (genetic) analysis have confirmed his insight. Darwin's finches are classified in three genera of the phylum Chordata, subphylum Vertebrata, class Aves, order Passeriformes, family Fringillidae, and subfamily Geospizinae (Questia Encyclopedia, 2004).
Darwin’s research was and still is a major break through in science. For a biologist they provide a wonderful opportunity to trace the evolutionary course of diversification and interpret it with ecologically relevant field observations. None of the species has become extinct as a result of human activities (Science Week, 2005).
The fact that these birds able to over come extinction due to human activity in their habitats is a great example of how evolution and natural selection is true and it really does work. Keep in mind that Darwin explored these islands back in 1835. Another great species to look at is us: the human population, we overcame it all. Although we now have advanced technology and medicine that helps to keep our species alive, we have come along way in the process of evolution.
Like the different turtles we observed in class, the finches have different sized beaks, talons, feathers, etc. These characteristics, when mating, were passed on to the offspring of the finches. There has been record of cross breeding/mating among two different finches from different islands, however, that seemed to just increase their potential because even the hybrid offspring survive quite well considering its circumstances. This is specifically when there is a rich supply of intermediate-sized seeds suitable for exploitation by birds of intermediate beak size. When they breed, they backcross to one of the parental species. Which one they breed with depends on the father, because when the time comes to choose a mate they do so largely on the basis of the song they learned from their fathers (Science Week, 2005).
Darwin and his theory of evolution and natural selection are very interesting. I believe that organism will forever be in this process because everyone wants to be the last one standing and able to reproduce and multiply to keep the genes alive.