In the middle of the twentieth century, demographic transition theory became the dominant theory of population growth. Based on observed trends in Western European societies, it argues that populations go through three stages in their transition to a modern pattern. Stage one (pre transition) is characterized by low or no growth, and high fertility is counterbalanced by high mortality. In Stage Two (the stage of transition), mortality rates begin to decline, and the population grows at a rapid pace. By the end of this stage, fertility has begun to decline as well. However, because mortality decline had a head start, the death rate remains lower than the birth rate, and the population continues to experience a high rate of growth. In Stage Three (post transition), the movement to low fertility and mortality rates is complete, producing once again a no-growth situation. The theory of demographic transition explains these three stages in terms of economic development, namely industrialization and urbanization. Since about 1980, demographic transition theory has been criticized on a number of grounds, including its assumption that the demographic experience of non-Western societies will inevitably follow that of the West; its failure to consider cultural variables; and its hypothesized relationship between population growth and economic development. Indeed, all three theories above contain assumptions about population growth and economic development; however, there is mounting evidence that this relationship is complex and varies from context to context. As the twenty-first century begins, the attempt to erect a general theory of population growth has been abandoned, signaling for some an alarming trend in population studies.
In the earlier theories of population it is mentioned that population increases fast but its rate of growth falls with the industrial development. Improved medical facilities also ensure low death rates. The historical sequence led to demographers to ask whether this process will continue with industrialization. The theory of demographic transition explains that a stage is arrived at where population tends to stabilized once a certain level of economic development is achieved. There are three stages of demographic transition. There are as follow: Stage I: In this stage both death rates and birth rates are high. Due to this reason population growth remain fairly stable. This stage is found in traditional societies. Stage II: In these stage birth rates remains high but death rates fall due to availability of medical facilities and better living standards. This stage is found in all developing societies. Population increases quite fast in this stage. Stage III: In this stage both death rates and birth rates starts declining and settle at a low level.
The functionalist perspectives on population
Malthus stated that, the populations of the world would increase in geometric proportions while the food resources available for them would increase only in arithmetic proportions.
In simple words, if human population was allowed to increase in an uncontrolled way, then the number of people would increase at a faster rate than the food supply. A point would come when human population would reach the limit up to which food sources could support it. Any further increase would lead to population crash caused by natural phenomena like famine or disease.
According to Malthus, human society could never be perfected. He believed that man is a lazy animal, who would lead a satisfied life and procreate as long as his family was well fed. However, as soon as human population would feel constraints in food supply due to increase in population, he would again work hard to provide enough for his family. This might lead to an increase in agricultural production to provide for all, but at the same time man would be back to his complacent stage, where all his needs would be...