Image credit

Image credit

ZIMSEC O Level Combined Science Notes: Population Dynamics

  • Population-all the inhabitants of a particular place/area at one given time
  • The study of changes in population is known as demograph

Factors affecting population change

  • The birth rate-the number of live births per 1000 people per year.
  • Death/Mortality rate-is the number of deaths per 1 000 people per year.
  • The death rate is Zimbabwe has been raised by HIV/AIDS
  • Infant mortality rate-is the number of deaths of babies less than 1 year old per 1000 babies born per year
  • The mortality rate of those 5 years and below gives an indication of the health services of a given country/area
  • Growth rate-Birth rate-Death rate
  • Migration-the movement of people in or out of an area,
  • In most countries migration is not an issue
  • In Zimbabwe a lot of people have emigrated due to economic hardships

Population growth

  • Doubling time-is the time it takes for the population to double
  • \text{Doubling time= } \dfrac{70}{\text{Percentage Growth Rate}}
  • Dependency ratio-the comparison of the number of children and old people to the number of productive adults
  • Children-those under 15 years of age
  • Old people-those over 65 years of age
  • \text{Dependency ratio = } \dfrac{\text{Number of elderly people + Number of Children}}{\text{Number of people of working age}}

To access more topics go to the Combined Science Notes page