How and why do populations change naturally?

How and why do populations change naturally?

1. Demographic transition model

   • Population pyramids models
     • Stage 1: Afghanistan
       • Birth rate stays equal /w slight increase
         • No birth control
         • High infant mortality
         • Children needed to work
       • Death rate fluctuates
         • Diseases
         • Poor hygiene
         • No/little health care
         • Famine/ malnutrition
         • War/ terrorism
       • Total population fluctuates
     • Stage 2: Bangladesh
       • Birth rates begin to slightly drop
       • Death rates dramatically decreased
         • Slightly better housing
         • Slightly better food/ water
         • Modest healthcare
         • Lower infant mortality
     • Stage 3: Mexicio
       • Birth rate drops
         • Birth control
         • Lower infant mortality
         • Desire for smaller families
       • Death rates continue to decrease
       • Total population rises
     • Stage 4: UK
       • Birth rate reaches a low point and fluctuates
       • Death rate levels off
         • Improved medical care (NHS)
         • Good quality housing
         • Easy access to food/ water
           • High wealth compared to LEDCs
     • Stage 5: Japan
       • Decreasing birth rate
         • Change in culture - desire smaller families
       • Level death rates
         • Medication becomes advanced
           • Natural deaths cause a level but low death rate
       • Total population decreases
         • As population hits a high resources cannot be shared equally
           • Total population must decrease to survive sustainably
           • Out-migration