Population change via natural change
Population change via natural change
You need to learn the following key definitions:
Birth rate: this is the number of births per thousand people per year.
Death rate: the number of deaths per thousand people per year.
Natural change: this is difference between birth rate and death rate. It tells you by how many the population will be growing per thousand of population per year.
All population change is a result of natural change or migration. You must have a clear understanding of the factors that affect natural change and the issues involved. You must also have a clear understanding of the causes and consequences of migration.
Natural change as stated earlier is the difference between births and deaths. For the population to increase births must exceed deaths. You will need to know the factors that affect birth rate and death rates. This can be studied effectively through the demographic transition model.
The demographic transition model shows how birth rates and death rates change as a country goes through different stages of development through clicking on the next button:
Birth rates and death rates are high so population is low and stable. This would include Amazonian rainforest people and subsistence farmers in Bangladesh.
Reasons for high death rates include, an unstable political society therefore possible civil unrest. Country could still be in reliant upon a subsistence economy therefore food supply is very unreliable. Water supply is likely to be unclean. There is very little medical care or social care. Disease and pests still have a dramatic effect on population.
High birth rates would be a natural consequence of the high death rates. Families have large families to compensate for the large infant mortality rate and so the children can work to support the families including parents during their old age. Large families become part of the culture and religion and men are seen as powerful if they have many children. Women's role in society is very much as a mother producing children.
Death rates fall but birth rates remain high. Natural increase is greater so population starts to grow rapidly. An example would be Sri Lanka or Peru.
The death rates have fallen as a consequence of a medical or social breakthrough. For example new hospitals, new vaccinations, or new legislation to prohibit children from working in factories. Alternatively improvements could be made to water supplies or food, accommodation - it will usually be a combination of events.
Birth rates remain high as culture and religion still dictates this. There is likely to be very limited access to family planning and women still have a very submissive role in society.
Birth rates now fall and death rates continue to fall. Natural increase is still high and population growth rapid. An example would be Chile or China.
Birth rates will start to fall as there is greater access to family planning. People will also start to appreciate the expense of a large family and opt for fewer children. The women are getting a better deal from society and has access to the job market so could opt to pursue a career instead of being a full time mother.
Death rates continue to fall as the country continues to improve medical and social care, sanitation, and living conditions.
Birth rates and death rates level out. Natural increase is low so population stabilises. Australia would be a good example of a country at the start of stage 4.
Society is advanced; women can pursue careers and live independent lives. Families opt for smaller families because of the costs involved.
Death rates remain low. There is little scope for further decline.
Birth rates fall below death rates so natural increase is now negative. Population will start to decrease. Japan and Italy are in this stage.
Birth rates fall further as people are waiting longer to have families. Parents are aware of the cost of children so have one or two so they can still have a good house, holidays - a good standard of living. Women have full access to the job market and family planning is universally accepted and available.
Death rates will remain very constant unless there is a major medical breakthrough to lower them or a war or other catastrophe to raise them.