Demography

Demography studies the statistics of human populations. Demography is usually used to study dynamic (constantly changing) populations. It covers the study of the size, structure and distribution of these populations and the changes in these populations due to do births, deaths, migration and emigration. Demography can also be applied to entire groups defined by nationality, religion and ethnicity.
Formal demography limits its object of study to the measurement of populations processes, while the more broad field of social demography population studies also analyze the relationships between economic, social, cultural and biological processes influencing a population.

The study of human populations has its roots, like sociology generally, in the societal changes that accompanied both the scientific and industrial revolutions. Some early mathematicians developed primitive forms of life tables, which are tables of life expectancies, for life insurance and actuarial purposes.

As more and more people leave villages and farms to live in cities, urban growth results. The rapid growth of cities like Chicago in the late 19th century and Mumbai a century later can be attributed largely to rural-urban migration and the demographic transition. This kind of growth is especially commonplace in developing countries.

Urbanization is often viewed as a negative trend, but can in fact, be perceived simply as a natural occurrence from individual and corporate efforts to reduce expense in commuting and transportation while improving opportunities for jobs, education, housing, and transportation. Living in cities permits individuals and families to take advantage of the opportunities of proximity, diversity, and marketplace competition.

The effects of urbanization may be an overall positive for the environment. Birth rates of new urban dwellers fall immediately to the replacement rate, and keep falling. This can prevent overpopulation. Additionally, it puts a stop to destructive subsistence farming techniques, like slash and burn agriculture. Finally, it minimizes land use by humans, leaving more for nature.

The population of South Korea has decreased more and more. There are various reasons for this.
Changing values, the increase in single women, and falling birthrate policy encouraged South Korea was conducted once is the cause. Low birth rate has caused many social problems. we have to take measures to solve this problem.