Argument essay
"Yello-legged frogs were once common in high altitude lakes in Sierra Nevada mountains, but they have become increasingly rare.Trout feed on tadpoles and young frogs. Few lakes in Sierra Nevada had any trout in them until a hundred years ago.At that time, many lakes were stocked with trout for recreational fishing, and now trout are common in virtually all bodies of water in Sierra Nevada.Researchers removed the trout from one lake, and frog population soon quadrupled. Since frogs are capable of moving several miles over land, removing trout from just a few lakes is clearly the way to restore the frog population to its former levels."
In above argument author tries to establish direct link between increasing population of Trout being responsible for dwindling population of yellow legged frogs and tadpoles. Author strongly argues that by removal of Trout from just few lakes, the frog population will be restored. Although the evidence and facts mentioned seem plausible but their perplexing nature does not help the argument to be qualified as valid.
Firstly author mentions about presence of Yellow legged frogs in high-altitude of Sierra Nevada montains hundred years ago which are almost extict now. But the envoirnmental conditions of high-altitude regions are subjected to varying climatic conditions. Author has failed to mention the degree of variation in the climatic conditions which are considered as foremost factors affecting the life and population of animals. In addition the vertebrates like frogs and tadpoles are coldblooded animals which are vulnerable to slight change in their habitat.Other envoirnmental factors that might have been responsible for dwindling population of frogs are calamities that may have occured over these high altitude topographical regions over this period of century.So while making the record of population changes author should also consider the climatic conditions, envoirnmental factors, calamities as vital parameters.
Secondly for sustaining the population and maintaining consistency in growth animals require appropriate conditions like mating place, availibility of food etc. Slight variation in any of these factors directly hampers the growth of easily susceptible animals like frogs and tadpoles.Further while making a comparison of any topograhical region over period of hundered years author fails to consider change in the sanctity of the region. In past the high-altitude Nevada mountains may have been very concealed and lonely place with no human activity. But after it was discovered as a place for recreational fishing their might have been increment in population of place because of tourism and industrialization. As a result of which pollution levels , fishing activities, sailing in lakes and other host of activities associated with fishing saw gradual rise which justifies decrease in frog population.
Author states that deliberate reduction in Trout population by scientist resulted in sudden increase in frog population by factor of four but he fails to mention the other conditions in lake such as food, climate, fishing activity which can directly affect the frog population. Further author strongly states that since frog migrate sevral miles over the land, removing Trouts from just few lakes would resotre the poulation. But once frogs start migrating to other lakes where there is dense concerntration of Trouts then those frogs inturn would be consumed by Trouts causing viscious circle. This would eventually result in disturbance in envoirnmental balance of the region.
Although author consciously presents sevral evidiences and facts supporting his argument but lack of solidity in them fails to justify it. Decrement in the Trout population will surely facilitate in restoring the frog population but experiment is needed to be carried in all lakes in the region with other conditions and factors maintained in order to favour the nourishment of frogs to achieve the desired result.
