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Evolution as an Adaptation Essay The Chipping Sparrow is found across most of North America and eats mainly insects an seeds that are found in suburban areas and in farmland in the United States (Chipping Sparrow). Since the early 1990s, the feeding range of the Chipping Sparrow has included farms that grow genetically-modified grains, including the corn and wheat that are part of the Chipping Sparrows traditional diet (Genetically Altered Wheat Promises Higher Yields). Genetically-modified seeds are used to develop crops that are resistant to disease or pests, that use less water, or that are needed for specific requirements such as for pharmaceutical uses. While these crops may be helpful to humans, this change in the food supply could have important implications for the evolution of the Chipping Sparrow and other animals (Chrenkova, Sommer, Ceresnakova, et al, 2002). Although Chipping Sparrows share enough common traits to qualify as a unique species, differences still exist between individual Chipping Sparrows. Some of these differences might include metabolic differences that affect the individual birds digestive process. It is possible that the genetically-modified corn, for example, could be missing an enzyme that is essential to the Chipping Sparrows digestive process. If this happened, then the majority of Chipping Sparrows would not be able to break down the modified corn and would not benefit from eating it. The birds might feel full, but an essential part of their diet would be missing. Unless they could find another source of food, these Chipping Sparrows would eventually die of malnutrition. It is also possible that a small number of Chipping Sparrows could have some genetic metabolic abnormality that made it possible for them to digest the modified corn without this particular missing enzyme. In fact, it is even possible that this genetic abnormality in these sparrows digestive systems had always existed and that earlier generations of Chipping Sparrows who had this trait tended to have shortened life spans. If this had happened, then this digestive trait would have been passed along, but would only be present in a small number of the sparrows who would have been less likely to reproduce. If this was the case, then the change in the food supply could turn what had been a genetic liability into a genetic benefit. The Chipping Sparrows that could digest the modified corn would survive and would pass this trait along to their offspring. Those that did not have the trait would eventually either die or migrate. The fate of the Chipping Sparrows that remained would not be decided by luck, but would be the result of a genetic mutation that proved to be beneficial in their new environment. The change in the environment would effect the Chipping Sparrow population in stages. First, the majority of Chipping Sparrows that were unable to digest the modified corn would either leave or die, resulting in a severe drop in the Chipping Sparrow population. The sparrows that had the gene for the digestive trait would pass it along to their offspring. Even if this was a recessive gene, the odds of it being passed along to future generations would still increase as the number of non-adapted sparrows and their effect on the gene pool diminished. Instead of only one parent carrying the gene, which may have been the case in previous generations, it would become more likely that both parents would carry the gene for this particular trait. To summarize, the original population at time zero would have thrived on naturally produced corn. Individual members of this population, however, may have had what was the equivalent of a food allergy that prevented them from getting the full benefit of this natural food source. The change in the corn would have turned this genetic disorder into a genetic benefit which would have been passed along to future generations. Eventually, the surviving Chipping Sparrows would evolve into a species that thrives on genetically-modified corn and is unable to digest natural, unmodified corn. References Chipping Sparrow. Avianweb. com (2006).Retrieved May 25, 2008, from http://www. avianweb. com/chippingsparrow. html Chrenkova, M. , Sommer, A. , Ceresnakova, Z. , Nitrayova, S. , Prostredna, M. (2002). Nutritional evaluation of genetically modified maize corn performed on rats. Archives of Animal Nutrition,56 (3), p229-236. Retrieved May 25, 2008, from Academic Search Premier. Genetically Altered Wheat Promises Higher Yields. New York Times (May 28, 1992). Retrieved May 25, 2008, from http://query. nytimes. com/gst/fullpage. html? res=9E0CE4DF1039F93BA15756C0A964958260