How Does Charles Darwin's Finches Constitute An Iconic Model

Darwin has listed different names for each bird, they are all variations of Finches, apparently descended from a common ancestor. However, each bird has a different length beak and many are differently shaped to allow them to more efficiently eat the available fodder. Coincidentally, Mr. Darwin failed to catalog specifically where each bird came from and had to ask the ship’s captain to supply this information along with his collection to Mr. Gould for identification and cataloging. An interesting part of the conversation between Mr. Darwin and the ship’s captain is the captain’s argument for the fixity of species, that each one was created by God exactly the way it was, and placed on each island, and that it is heresy to say that they came to be there any other way.

The Beak of the Finch by Jonathan Weiner explores evolution through the most famous examples in history—the finches of the Galápagos Islands. Charles Darwin’s theory of natural selection and the process of evolution are applied directly to what scientists refer to as Darwin’s Finches. Weiner follows scientists Peter and Rosemary Grant as they study the finches in real time on the Galápagos. Years of previous work, study and data is collected and analyzed. Different species of animals are observed and explained throughout history. The Grants have one goal, and that is to find the origin of the species, how organisms first began. They find that it really is about the “survival of the

The Evolution Lab simulates environmental situations to determine effects on evolution over periods of time. This lab experiments with the evolution of finches on two different islands over 100, 200, and 300 years. By manipulating parameters that influence natural selection, the effects that natural selection have on the evolution process can be studied.

One of its most important characteristics is its beak. The finch adapted to have a thin, long beak to probe through moss, bark and leaves in search of food (Wildscreen Arkive, N.D.). These finches have the thinnest beak out of the 13 finches; which aids them to find small insects. The Green Warbler finch are mostly found in humid highland forest where their primary food source is found. These adaptations made them more fit to survive on available food. Over the years the finch’s beak has evolved as the bird developed different taste for insects. Another famous adaptation is how they camouflage in their environment. The Green Warbler is restricted to the forest and is greener in body colouration, while the Gray Warbler is found in shrubby, dry thickets and is greyer and duller looking (Certhidea olivacea, 2010). Their coloration helps them camouflage in their own environments, and to hide from predators. Recent studies have found that there are in fact two separate species of the Warbler Finch, the Green Warbler Finch and the Grey Warbler Finch, but are considered as a single species (Wildscreen Arkive, N.D.). The Green Warbler finch mainly occupies larger, inner islands, while the Grey Warbler finch inhabits the smaller, outer islands (Green Warbler Finch,

In 1977 a drought reduced the number of small seeds available for the birds, forcing them to rely on larger seeds and nuts, which were difficult for birds with smaller beaks to open. The number of birds unable to eat reduced as they died and gave way to harder beaked finches. Within a couple of generations they had evolved larger beaks. In 2003 another drought struck the Galapagos and as there were many large beaked finches, the food source of nuts dwindled, making the ability to eat smaller seeds an asset. The numbers of larger beaked birds dwindled as food became scarce, leaving the smaller birds to survive and reproduce. Darwin’s theory was not well received when first written in On the Origin of Species, though many scientists today use it as a basis for research in evolution.

10. Study Figure 1.22, which shows an evolutionary “tree.” What is indicated by twig? What do the branch points represent? Where did the “common ancestor” of the Galápagos finches originate?

After watching the video on Finch evolution, and completing the gizmo, I have found many correlations between the finch population, and the climate of the Galapagos Islands. The Finches beak size was dependent on the climate, and natural selection. The population of the birds increased and decreased throughout the years because the extreme climate changes and the process of natural selection.

On the Galápagos Islands off the coast near Ecuador we studied the behaviors of the animals, plants and environment on Daphne Major we found that the lack of rainfall during the wet season of 1977 caused most of the plants to produce less seeds and thus most of the medium ground finches died of starvation as their main food source had become scarce. Although the lack of seeds some finches were able to survive with their longer and bigger beaks. They were able to survive because their beaks were able to break open the harder and more plentiful Tribulus seeds that survived the dry season of 1977.

“These birds look similar to each other in plumage and song, yet closer observation reveals that they all differ from one another in how their beaks look and work” (Abzhanov, A., 2010). Darwin believed that if given enough time, a species would adapt to its environment, “It is not the strongest of the species that survives, nor the most intelligent that survives. It is the one that is most adaptable to change” (Darwin, C., 1859). Charles Darwin recognized that natural selection was the primary factor for evolution, not limited to only birds and plants, but to humans as well.

Probosciger aterrimus, better known as the “palm cockatoo”, is the largest bird species of the parakeet (Psittaciformes) family (Taylor 2000). This highly threatened cockatoo species can be found dwelling in many tropical and woodland regions, including those of lowland New Guinea and the savanna habitat of Cape York Peninsula, Australia (Murphy et al. 2003), and can be identified by its long, plumaged body, curled erectile crest, and naked cheek patches. Of particular interest, and perhaps the most distinctive of this cockatoo’s traits, is the long, strong hooked beak. As with many bird species, the palm cockatoo’s bill has adapted to its specific dietary preferences and feeding strategies; in particular, the shock absorbing ability of the large, powerful bill allows the granivore-frugivore (grain or seed-eating – fruit-eating, respectively) (Koutsos et al. 2001) parakeet to scavenge for hard nuts that are otherwise inaccessible to other parakeet species. Further supporting the granivorous diet-accommodating beak morphology of the palm cockatoo is a study conducted by Munshi-South and Wilkinson (2006) that conclusively correlated the evolution of longer lifespans in parrots with the adoption of seed-based diets. If parrot species do in fact achieve longer lifespans by adopting granivorous diets, natural selection’s favoring of traits maximizing the adoption of a granivorous diet in the palm cockatoo should be relatively equally distributed amongst all members of the

The Character Evolution of Three Youngsters “We don’t grow when things are easy; we grow when we face challenges” (Joyce Meyer). As the story progresses, Jem and Scout stumble upon many challenges, that help them develop into maturity The novel, To Kill a Mockingbird, evolves around the three main characters; Atticus Finch, an attorney, Scout Finch, and Jem Finch. This novel takes place in the southern Alabama, where racism has already taken its toll. Atticus Finch takes action towards racism by defending Tom Robinson, a poor African American falsely accused of raping a white girl, Mayella Ewell. As the story progresses, Jem and Scout, along with their friend Dill, stumble upon many challenges that help them develop into maturity.

Some reasons why beaks were thought to be so useful for testing Darwin’s theory of natural selection was because it seemed that the more favorable variations in their beaks will be passed down. Another reason was because there were more variations in the beaks depending what the finches ate so he could study a variety of beaks.

Krichman (2009) examined the ancestry of flightless birds (Gallirallus philippenesis) through the usage of genetic testing that were sampled throughout a range of ancestral species. This was to test a model of speciation where flightless birds were thought to have evolved from flying birds

Darwin’s theory of evolution is the most commonly accepted theory because of the strong evidence that the theory is built on. One of the most famous examples of Darwin’s theory is the Galapagos finches. Darwin observed different finches from different islands of the Galapagos. He found that the finches from all the different islands had differently evolved beaks. Darwin

When that happens over many generations a species’ gene pool changes to only include the traits that are a best fit for ensuring survival of that species, and a new species may evolve. In the case of the Galapagos finches Darwin studied, biologists have since found that one of the differences was their beak size, which were adapted to the specific seeds available to the finches as food on the different islands. This would support this principle as only the birds able to eat the local seeds would be able to survive to reproduce, thus over many generations, new finches with a variety of different beak sizes would “evolve”. The