THE UNDERLYING THEORIES AND MODELS OF POPULATION

1. Malthusian Population Theories

• Malthus argued that "Population grow at a rate that exceeds available food supply"
• Population can survive only because of positive checks on population growth. That is, in mortality due to famines, epidemics, wars and natural causes, preventive checks e.g. abstinence and contraception.

2. Neo-Malthusian

• Contemporary follower of the Malthus ideas
• They focus more on the health and mortality consequences of a changing environment e.g. Each argue that the impact on the environment is a function of population size, level of affluence and technology.

  
  
  

3. Marxist Theories

• In Marx's view, population growth is closely linked to the mode of production and level of development.
• He argued that there are too many poor people due to capitalist exploitation.
• Proper economic and social arrangements could accommodate population growth.

4. Demographic Transition Theory

• Follow demographic theory of Europe.
• When the population has a high rate and high death rate that population will not grow. That is, population growth is equal to zero.

This theory has four stages

• Stage I : Low Growth

-If the population has a very high and varied birth and death rates due to poverty and poor sanitation, there will be virtually low population growth.

-Most of human history was spent in stage I.

-Currently there is no stage I country today.

• Stage II : High Growth

-In this stage, Death rate drops due to: Improved sanitation and food nutrients.

-Countries in Europe and North America entered stage II in the late 18^th-19^th century.

• Stage III : Moderate Growth

-Birth rate begins to drop sharply due to industrialization and changing attitudes towards ideal family size.

-Death rate continues to fall but at a much lower rate than in stage II.

-Population continue to grow at a more moderate rate.

-Countries in Europe and North America entered this Stage during the first half of the 20^th century. Some countries in Asia, Africa and Latin America entered Stage III recently.

• Stage IV : Low Growth

-Birth rate decline to the point where it almost equals to the death rate.

-Natural growth rate approaches to zero.

-Sweden, Denmark, Germany, U.K have entered stage IV

STRENGTH OF DEMOGRAPHIC TRANSITION THEORY

1. Strongly descriptively.
2. It provides trends in birth and death rate in western countries during the Industrial Revolution.
3. Demographic transition, as a framework is useful for classifying population. Example, developing nations belong in stage I or II while developed nations fit in stage III or IV.
4. Demographic transition has predict population growth.

WEAKNESS OF DEMOGRAPHIC TRANSITION THEORY

1. Poor explanation of population change, it does not specify mechanism of such change.
2. Progress through demographic transition is not automatic.
3. It fails to account for any reversal that might occur in the process.
4. It is silent on the role of migration.

5. Epidemiological Transition Theory

• Explains pattern of health and disease and its influence to mortality.
• Base on patterns experienced in developed countries.

Has four stages

• Predominant of famine and pestilence
• Decline of infectious diseases.
• Rise of degenerative diseases.
• Rise of "hubristic" behavior (smoking, unprotected sex)