Model of population cycle

 

The model of population cycle refers to the transition from high birth and death rates to low birth and death rates as a country develops from a pre-industrial to an industrialized economic system. 
    
The model of demographic transition progresses in four stages:

-Old or preindustrial demographic regime: death rate and birth rate were both very high.

-First transition: the Industrial Revolution leads to a fall in death rate and an increase in population.

-Second transition: the birth rate begins to decline, and mortality is still down.

 

-Modern demographic regime: Mortality and birth rate are both low. In some places (like Galicia), the mortality rate is higher than the birth rate. This leads to a natural decrease.