Evolution & population Essay

Custom Student Mr. Teacher ENG 1001-04 22 October 2016

Evolution & population

Evolution occurs in levels of population. Natural selection is one mechanism of evolution. It is a process that enables organisms to adapt to their environment by means of heritable characteristics. Darwin’s finches are termed as the symbol of evolution. Finches are species of Passerine birds. There are about 14 species of finches known today and most of them are found in Galapagos Island. To be specific, thirteen species are found in Galapagos Island and only 1 in Cocos Island. These species are similar in most ways except for one characteristic which is the shape and size of their beaks.

These birds are sparrow sized birds with gray, brown or black feathers. They also have short and rounded wings and a rounded tail. Finches are generalized feeders but can be specialized feeders when little food is available. An evidence of evolution in Darwin’s finches is their varying size and shape of beaks. These finches came from a single species but by means of natural selection has developed specialized feeding structures. Each species has a different size and shape of beaks that best suits their need as each species differ in the types of food they eat during dry season or when less food is available.

Some have crasping bills, probing bills and grasping bills. Camarhynchus pallidus is one of the many species if Darwin’s finches. It belongs to the Embirizidae family. These species can be found in Galapagos Island. The size ranges f5rom ten to twenty centimeters. It has a dull, light grayish to olive coloration. It also has a uniform coloration patters. A long and pointed beak is the adaptive characteristic of this species. Their long and pointed beak enables them to probe holes ion trees to catch their food. Change in beak color is also a unifying characteristic of this species. Upon maturation, its beak turns from pink to black.

This species of finches feeds on invertebrates and other small insects that mostly live in barks of trees. It uses its beak to dig a hole in the tree and afterwards inserts a twig or spine to scoop out the insects. It uses twigs or cactus spine in order to get its preys. Unlike woodpeckers which have long barbed tongues, wood pecker finches have a relatively short tongue. The use of these tools is needed to compensate for the short tongues of these birds. But before they can get their prey using their tools, they should first find the appropriate length that will reach the exact location of their target.

One major evolution that might happen in this species would be the length of their tongue. Longer tongue, like those of the wood peckers, will make it easier for them to catch their prey. They would not go through trial and error process in order to get the exact tool necessary for their feeding. They would not even need the aid of tools such as twigs and spines if they will have longer tongue. So that in any case woodpeckers would migrate to Galapagos Island, they can survive their presence. References: Galapagos Online (2004, January 25). Darwin’s Finches. Retrieved May 23, 2009, from http://www.

galapagosonline. com/Galapagos_Natural_History/Birds_and_Animals/Birds/Darwins_Finches. html Grant, PR and Grant, BR (1997). Genetics and the origin of bird species. Proceedings of the National Academy of Scienmces, 94, 7768-7795 Grant, PR, Smith, JNM, Grant, BR, Abbott, IJ and Abbott, LK (1975). Finch numbers, owl predation and plant dispersal on Isla Daphne Major, Galapagos. Oecologia, 19, 239-257 Charles Darwin Foundation for the Galapagos Islands (2007). Darwin’s Finches. Retrieved May 23, 2009, from http://www. darwinfoundation. org/files/species/pdf/finches-en. pdf

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