Population Growth

Population Growth

Definition : Population growth is defined as the increase in. the number of human inhabitants of a given place.

There are the main components of population growth. .

(i) Fertility (ii) Mortality (iii) Mobility (migration);

Dynamics of Population Growth While the facts of birth and death at an individual level are dear, their effect on the growth and decline of a population (that is, a collection of individuals) is more opaque. Here we look at the process which shape population growth and the kind of yardsticks we use to measure it. In this chapter we shall be concerned mainly with the human population. Much of the reasoning we shall use could, however, be applied to animal populations as well

Births, Deaths, and Growth: The total population of any area of the earth’s surface- represents a balance between two forces. One is natural change caused by the difference between the number of births and deaths. If births are more numerous than deaths in any period, the total population will increase. If they are less numerous, it will decrease. This simple relationship is modified by a second force; migration. When immigrants are more -numerous than emigrants, There Will be a population increase. (This assumes, of course, that we are ignoring natural change for the moment). When emigrants are more numerous, there will be a population decline.

As figure -7-1 shows, net changes in population totals are caused by the interaction of four elements: Births and immigrants tend to push the total up : deaths and emigrants tend to bring the total down. Although migration-may be the most important factor in small areas (for example, in a small village or a city block), it is less significant on the national level. For the world as a whole, migration is irrelevant because all movements take place within the limits of the recording area. In other words, until interplanetary travel comes along, the planet Earth can be safely treated as - a closed system for demographic purposes. We shall therefore concern ourselves in this chapter with the natural change component, leaving the more complicated analysis of open population systems (in which migration is significant).

1. Fertility: This is defined as the actual number. of live births in a population unit in one year, while �cohort fertility’ is the number of live births for a group or cohort of women during their span fertility of reproduction. Actual live birth - is thus constrained with �fecundity’ in demography, which, is the potential capacity for biological reproduction. The principal factors in influencing fertility in a population are the age of marriage, the availability of contraception and attitude towards family size. A decline in fertility is characteristic of urban, industrial societies and has significant social and economic consequences for the size of work force.

Fertility rate is determined by the number of children born every year to 1000 women of child bearing age (15-45 years). The crude birth rate is given by number of live births per thousand persons of all ages in one year. So birth rate is easier to record by simply knowing population of a an area and knowing the number of births in a years,, it is determined, dividing to 1000’

2. Determinants of fertility: Fertility is influenced by many factors, most important few are,

1. Per capita income, percentage of population in the reproductive age group; percentage of rural population and percentage of, literacy etc. �

2. Fertility is very, much affected by changes in age at marriage. Spacing �in marriage is closely related to social, economic and cultural conditions

3. Economic status of people influences fertility. Poverty, with it’s associated factors such as illiteracy, ill health and poor diet etc. keeps the birth rate high Poverty limits the alternative arrangements for recreation and enjoyment. Death rate is usually high among the poor people. Therefore, they tend to have more children.

4 Religion and social attitudes are important factors (as is evident from reaction of different religious groups over Cairo & Beijing conferences of 94-95). So where people are tradition oriented and fatalistic, the birth rate is generally high.

5. Illiteracy and ignorance are also responsible for high growth. Climatic conditions affect fertility. In countries where climatic conditions are hot population attains puberty at an early age and number of years before a menu-pause. to women are more, thus fertility is high in warmer