Human Population

• Births
• Deaths
• Immigration 
• Emigration

(Births+Immigration) - (Deaths+emigration)

change in population multiplied by 100, divided by the population at the start

Number of births/deaths per year divided by  total population that year

Births-deaths per year divided by total population per year

A diagram showing the age structure of a population with bars denting the percentage of males and females at each age range

• Narrow base (low birth rate)
• Vertical sides (low infant mortality rate)
• Tall height (many survive to old age)

• Wide base (high birth rate)
• Sloping sides (high infant mortality rate)
• Short height (few people surviving to old age)

A graph showing the lifespans of individuals from a sample group of 10,000

By looking at the age when 50% of the population are still alive

The size of a population plotted against time

• Food supply
• Safe drinking water
• Effective sewage disposal
• Effective medical care (vaccinations)

• High stationary: High birth and death rates 
• High infant mortality and short lifespans due to starvation and disease
• Population remains low and stable

• Early expanding: Population increased due to high birth rates.
• Better nutrition and less disease decreases death rates

Late expanding: Birth rate lower due to birth control and less dependance on children to contribute to income

• Low variable: Stable population Low birth and death rates 
• Greater proportion of old people in the population