The Human Population

The Human Population

Demographic transition is a model used to show the process of high birth rates and high death rates to low birth rates and low death rates as a society modernize. This model is based on a 1929 interpretation by Warren Thompson, and American demographer, who observed prior changes, or transition in birth and death rates; over the past two-hundred years, as society began to modernize.

The Demographic Transition (DMT), consist of four transitional stages; phase one of the transitional stage is characterized by the high birth and death rates. The second transitional phase is the declining death rate which is usually attributed to the advancement in medicine, improvement in medical care, and new initiatives, focusing on healthy living. However, there is no corresponding decline in birth rate, and during this phase there is increasing population growth. The third transition phase is characterized by declining fertility rates; and the fourth and final phase is when both birth and death rates reaches a somewhat equilibrium, at which the population becomes stable (Hamilton, 2013. p. 7).

A country's population may be defined as a potentially stable state between births, and deaths, immigration and emigration. Below is a model showing population size which is determined by birth and deaths. The number of births represents the birthrate population, as the death rate is similarly calculated. Therefore, from this depiction if births exceed deaths, then the population will increase in size (Rueter, 2003).

Population Size

Births Deaths

Birth rate Death rate 

The Human Population

Crude birth and death rates are the number of births and deaths per thousand of the population respectively, per thousand of the population per year. In initiating this data per thousand of the population, populations in different countries are compared, despite their total size. The term crude is used as no attention is given to what proportion of the population is old or young, female or male. In subtracting the crude death rate from the crude birth rate supplies the increase or decrease per thousand per year. Upon dividing these results by ten will relinquish the percent increase or decrease of the population (Wright & Boorse, 2011, p. 216).

Crude death rates were high throughout most of human history, at 40 percent per thousand in a majority of societies. During the middle of the 19th century, however, epidemics and other social factors accounted for high death rates began to level off, and Europe and North America began to see a decline in death rates. This decline was gradual in the now developed countries,