# Population Sizes Throughout History: The main cause of our rapid population increase is the decrease in the death rate. With new medicines and technologies,

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Population Sizes Throughout History: The main cause of our rapid population increase is the decrease in the death rate. With new medicines and technologies, people around the world are living healthier, longer lives. Throughout history, there have been three major surges in world population. These were the invention of tools and fire, the agricultural revolution, and then finally the industrial revolution. How to calculate population change: Population change = (crude birth rate + immigration)- (crude death rate + emigration)

Calculating Actual Growth Rate: You can calculate the actual growth rate of a place by using the formula: Actual Growth Rate (%) = (birth rate-death rate)/(10) Example: The US had a birth rate of 14.6 live births per 1,000 population in one year, compared to India’s birth rate of 22.2 in that same year. The death rate in that year for the US was 8.3 deaths per 1,000 population, compared to India’s rate of 6.4. US: (14.6-8.3)/10 = 0.6 India: (22.2-6.4)/10 = 1.6

Population Distribution: Between 2000 and 2030, most of the growth the earth will experience will be seen in developing or underdeveloped countries in Africa, Asia, and Latin America. Countries in Europe and North America will experience growth rates of 1% or less. Some countries such as Germany will even experience negative growth rates as fewer children are born in these well developed countries.

Fertility Rates: Replacement level fertility: this is when a couple has enough children to just replace themselves, so two per couple. RLF rates are lower in moderately developed countries and higher in less developed countries. This is because of the infant mortality rate. The Total Fertility rate is the average number of children a woman will have in her lifetime. The world’s population is growing so quickly because of the higher than replacement level fertility rates in under developed nations.

Factors Affecting Fertility Rates: Declines in fertility rates occur largely in urbanized areas. This comes from a lack of a need for children to work and provide for a family. In urbanized areas, there is also more access to contraceptives and family planning methods. The two main effects of having a lower than replacement level fertility rate are population decline and population aging.

Growth Rates and Doubling Times: The nineteenth century saw the greatest population growth in history. This means that the growth rate was very high and the time it takes to double the population was very low. Rule of 70: To find the doubling time of a population, divide the number into 70. For example, is the growth rate of a place is 2%, you would do 70/2 so the doubling time is 35 years. To find the growth rate, you would reverse this process and do 70/doubling time.

Demographic Transition: The name given to the process that has occurred during the past century. Leads to a stabilized population. The Four Stages of Development: 1. Pre-Industrial: severe living conditions. Poor medical care. Limited food. High death rate and high infant mortality rate. 2. Transitional: Advances in hygiene and food availability. Leads to an upward trend in population. 3. Industrial: Urbanization decreases the economic incentive to have children. Great food access and medical care. More education for women with a discouragement for large families. 4. Post Industrial: Birth rates equal mortality rates. No population growth.

Age Structure Diagrams: http://www.geography.hunter.cuny.edu/~tbw/ncc/Notes/ Chapter6.pop/chapter.6.pop.age.structure.outline.html http://www.geography.hunter.cuny.edu/~tbw/ncc/Notes/ Chapter6.pop/chapter.6.pop.age.structure.outline.html