class november 16

Population structure:

-      Sex ratio: Defined as the number of males per 100 females in the population. Developed countries have more females than males because they tend to love longer. 

The demographic transition

-      It is a model consisting of 4 stages that helps to explain the rising and falling of natural increase over time in a country. Historically no country has ever reverted back to a stage

-      Thus, the model can be thought to have a beginning, middle, and an end. 

-      Stage one: low growth- marked by very high birth and death rates

-      Stage two: high growth- marked by rapidly declining death rates and high birth rates

-      Stage three: moderate growth- marked by rapid decline in birth rates, steady death rate

-      Stage four: low growth- marked by very low birth rate and death rate. 

Declining birth rates:

Two successful strategies for low birth rate:

1.    Improving education and health care

2.    Contraception: more immediate results