In the past century, the steady growth of the human population and the corresponding increase in agriculture and pesticide use have caused much harm to wildlife in the United States,birds in particular. Unfortunately for birds, these trends are likely to continue, with the result that the number of birds in the United States will necessarily decline.
First, as human populations and settlements continue to expand, birds’ natural habitats will continue to disappear. Forests, wetlands, and grasslands will give way to ever more homes, malls, and offices. As the traditional areas suitable for birds keep decreasing, so will the size of the bird populations that depend on those vanishing habitats.
Second, agricultural activities must increase to keep pace with the growing human population. The growth of agriculture will also result in the further destruction of bird habitats as more and more wilderness areas are converted to agricultural use. As a result, bird populations in rural areas will continue to decline.
Third, as human settlements expand and agriculture increases, the use ofchemical pesticides will also increase. Pesticides are poisons designed to kill agricultural and home garden pests, such as insects, but inevitably, pesticides get into the water and into the food chain for birds where they can harm birds. Birds that eat the poisoned insects or drink contaminated water can die as a result, and even if pesticides do not kill birds outright, they can prevent them from reproducing successfully. So pesticides have significantly contributed to declines in bird population, and because there will continue to be a need to control agricultural pests in the future, this decline will continue.
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The reading and the lecture provide a heated debate concerning human culpability of the decrease in birds’ population. While the reading states that the increasing in human population poses many threats to the existence of many birds, the reading disagrees with that perspective, saying that there are many methodologies have been carried out in order to mitigate the damage. Moreover, the lecture also says that the reading do not take into account the benefits of the increasing in human population.
First of all, the reading manifests that since the increase in human population is inexorable, there will be no cessation in the expending of human settlements. Therefore, more and more birds’ natural habitats will disappear since they are superseded by houses, malls as well as offices. However, the lecture opposes this argument and says that the expansion of human accommodations actually provides habitats for other types of birds. It is pointed out that there a large number of seagulls as well as pigeons walking on the streets nowadays. Moreover, since pigeons are preys for hawks and falcons, these birds are inclined to move their habitats to the areas where pigeons are available, which are also places where human live. Therefore, the lecture rebuts the argument of the reading.
Second, agricultural activities must correlate with the growing population of human. In fact, the growth of agricultures means more and more wilderness areas will be transformed in order to fulfill the agricultural purposes. As a result, this wide-range transformation of the rural areas will inflict damage to the population of birds living in these areas. The reading, on the other hand, casts doubt on this argument and states that less and less rural lands are converted to agricultural use as more productive crops are being introduced. Since these special crops still provide the sufficient food source for the growing population, the population of birds will no longer decrease as their habitats are being conserved. This is another place where the lecture puts the reading under rigorous scrutiny.
Last but not least, the reading indicates that the increasing use of pesticides will also harm the population of birds. Since pesticides are chemicals that are treacherous to living species, especially pests, pesticides can pose a serious threat to bird population as pests are their preys. Moreover, pesticides also thwart the reproduction of birds, it will contribute to the aggregate decrease of bird population. Nevertheless, the lecture challenges this point and cites that there are two developments which will successfully alleviate the problem. The first of which is the introduction of new and less toxic pesticides. The second improvement is that there are new genetically modified crops that can resist to pests by themselves without the help of pesticides. Therefore, the lecture refutes the argument of the reading.
TOEFL listening lectures: A lecture from a life sciences class