1. Human Population Size

2. Questions for Today: What are the Major Factors that affect Human Population Size? How are fertility rates analyzed? What are the factors that affect Birth and Fertility Rates? What are factors that affect Death Rates? What factors affect Migration?

3. Factors that affect Population Size There are three factors that affect population size: Births (fertility) Death (mortality) Migration Remember the formula to calculation Population Change: Pop. Change = (B + I) – (D + E)

4. Population Change For the most of human history, the human population roughly grew at a slow pace. Within the past 200 years, that rate has increased significantly. Our current rate is roughly, 1.22% 82 million people were added to the world in 2008. An Average of 225,000 people are added daily 2.4 people are added every time your heart beats. http://www.worldometers.info/

5. Population Change Three major factors account for this major increase: Our ability to invade new ecosystems and adapt fast. The emergence of agriculture The development of sanitation, antibiotics, and vaccines.

6. Factors that affect Population Size Demographers use the crude birth and death rate to calculate population change: Crude rates are determined by looking at the number of births and deaths per 1,000 people in a population. An estimated and extrapolated number.

7. Fig. 6-3, p. 126

8. Fertility Rates Demographers also take in consideration Fertility Rates when calculating Population Statistics. Fertility rates are the number of children born to a woman during her lifetime. Two types of fertility rates: Replacement-level fertility rate Total Fertility rates

9. Fertility Rates Replacement Level Fertility Rates The average number of children that couples in a population must bear to replace themselves. Ranges from 2.1 in developed countries to 2.5 in developing countries.

10. Fertility Rates Total Fertility Rates: The average number of children born to women in a population during their reproductive years. The average world wide is 2.6 children per women. 1.6 in developed 2.8 in developing

11. Factors that affect Birth Rates There are 10 factors that affect Fertility rates: Child Labor Cost of raising and Education Availability of private and public pension systems Urbanization Educational and employment opportunities for women. Infant Mortality Rate Average age of marriage Availability of legal abortions Reliable Birth Control Religious Beliefs and Cultural Norms.

12. Factors that affect Death Rate The boom in Human population growth is not primarily caused by the birth rate. Our Death (Mortality) Rate has significantly dropped. Death Rates have dropped due to: Increased Food Supply Better nutrition Medical Advances Improved Sanitation Availability of Clean Water

13. Factors that affect the Death Rate Two statistics used by Demograpghers: Life Expectancy 1955: 48  2008: 68  2050: 74 Worldwide In the US, the Life Expectancy is 78 Infant Mortality Rate

14. Life Expectancy Two major factors that affect Life Expectancy in the US: Poor Healthcare across the Nation Obesity

15. Infant Mortality Infant Mortality is one of the best measures of a society’s quality of life Reflects general nutrition and pediatric health care Three factors affect Infant Mortality Rates in the US: Inadequate Health Care Drug addictions among pregnant women High Teen Birth Rates

16. Migration Migration is affected by the economic and social problems of other countries. Most people leave countries to pursue better opportunities in another. Jobs Healthcare Political Opposition Religious Intolerance