Structure of population

In population studies, the structure of a population is determined by certain characteristics such as population density, dispersion, age structure and sex ratio. Let us understand these terms.

Density represents the number of individuals of a species inhabiting a unit area. It reflects the success of a population. The complete count of individuals in an area is called census. Such censuses have been regularly conducted in our country. The last census was completed in the year 2001.

The process for Census 2011 has already been initiated in:

Japan (332 sq km-2), the Netherlands (456 sq Km-2), Bangladesh (915 sq km), Islands of Malta (1163sq km-2).

Dispersion

Dispersion pattern of a population is the dispersion of its individual members relative to one another in a given area. For example, human population, it is not uniformly dispersed. Only one third of the total land area is inhabited by humans. Even out of the one-third, some areas are sparsely populated while others are densely populated. The distribution variation depends on the availability of the requirements of life. About 56 per cent of the world’s population resides in Asia.

Study of the age structure is important because it provides

• Current and future status of age profiles
• Possible effects on environment
• Insights into population history
• Available and future work force (15-59 years)/manpower
• Status of elderly people needing social support, now and in the future
• Projection of current, future educational needs
• Projection of job needs
• Projection of medical/social/housing/healthcare needs economic status of the society
  

The problems arising out of increase in population density are alarming, some of them are:

• Decrease in per capita income
• Limited resources for immediate human need
• Dearth of natural resources such as water, land, fuel
• Price rise resulting from shortage of essential goods
• Disparity resulting from non-availability of essential goods
• Occupation of land mass for housing/industry purposes
• Decrease in agricultural space
• Decrease in farm output and forest cover
• Increased susceptibility to disease
• Increased demand for healthcare services
• Fall in job ratio leading to unrest
• Lack of adequate educational facilities; lowering of standards,
• Increased number of uneducated people;
• Lack of proper sanitation
• Increased pollution of air, water and soil
• Overall harmful effects on human health.
  

Sex ratio

Ideally, there should be a balance in the number of males and females in a population. However, in nature, there are more male births than female births. If there is no discrimination on the part of the society, the sex ratio of a population should remain more or less constant or balanced. Any deviation from this balance is not desirable for the population.

In our country, there were 972 females per every 1000 males (i.e. sex ratio is 972) in 1901. By 2001, the sex ratio fell to 933 females for every 1000 males. There are, however, very sharp regional differences. For example: in Kerala and Pondicherry, the sex ratio is 1058 and 1001 respectively, in Delhi (821), Haryana (861), Punjab (874), Chandigarh (773).

Age structure

In a population, individuals are of different ages. The proportion of individuals in each age group is called age structure of that population.

Group Age group 1911 1921 1931 1961 1971 1981 1991

Adults 0-14 38.8 39.2 38.3 41.0 41.4 39.7 36.5

Children 15-60 60.2 59.6 60.2 53.3 54.4 54.1 57.1

Old 60+ 1.0 1.2 1.5 5.7 5.2 6.2 6.4