Key Questions: Where is the world’s population increasing and decreasing? What do these measures tell us about a country’s population? What kind of general trends can we develop using these trends?
Population trends can be determined by the natural increase, fertility, and mortality.
The natural increase rate (NIR) measures the population growth. It is computed by dividing the crude birth rate (CBR) by the crude death rate (CDR). The CBR is the total number of births for every 1,000 people in a year. The CDR is the total number of deaths for every 1,000 people in a year.
Fertility rate (TFR) measures the number of births in a society; it is the average number of children that each woman has throughout their life.
Mortality can be measured by the infant mortality rate (IMR) which is the number of deaths each year of infants under a year of age compared to the total number of births and life expectancy which measures the average life span of a newborn can expect at current mortality levels.
Summary: The TFR or total fertility rate, and IMR or Infant mortal rate help compose each countries overall Natural Increase rate, or the percentage by which a population grows in a year. In LDC’s a lack of contraceptives contributes to the high fertility rate, and poor health care as well as unsanitary conditions influence the countries high mortality rates.This keeps LDC’s in stage 2 or 3 of the demographic transition where the countries face unbalanced measures of population. In MDC’s the IMR (infant mortality rate) has significantly decrease due to the industrial revolution which promoted sanitation and improved health care. Due to the decreasing IMR, MDC’s began encouraging smaller families and an increase use of contraceptives decreased MDC’s overall total fertility rate. This lowering in the fertility rate helps MDC’s enter stage 4 of the demographic transition model where the population begins leveling off, and find an equilibrium. However, MDC’s mortality rate is actually higher then that of LDC’s due to the fact that those living during prior stages of the demographic transition are beginning to die off.
Links for more info:
1.http://www.worldbank.org/depweb/beyond/beyondco/beg_03.pdf
2.http://www.globalchange.umich.edu/globalchange2/current/lectures/human_pop/human_pop.html
