HUMAN POPULATION

1. HUMAN POPULATION

2. History • Has grown slowly during most of earths history • Last 200 years, has experienced rapid exponential growth • J- shaped curve • S- shaped curve

3. Exponential growth Carrying Capacity – number of organism that can be supported in a given area • The earths population is growing at a very fast rate, currently at 1.14% per year.

4. Factors for the increase over history: • Ability to live in different habitats and or climate zones • Evolution of agriculture • Development of sanitary conditions, antibiotics, and vaccines • Discovery of fossil fuels

5. 5 most populous countries (2013) • China –1.35 billion • India – 1.2 billion • USA – 316 million • Indonesia – 251 million • Brazil – 200 million

6. Factors affecting population size • Number of births (birth rate) – number of live births per 1000 people in a given year • Number of deaths (death rate) – number of deaths “ “ • Migration (immigration or emigration)

7. Fertility – number of children born to a women during her lifetime • Replacement-level fertility – number of children a couple must have to replace themselves • Need to average 2.1 children per women for 50 years for population to level off.

8. Factors affecting birth rates • Importance of children in the labor force. • Cost of raising and educating • Availability of private and public pension systems • Urbanization • Average age of marriage • Availability of reliable birth control methods

9. Factors affecting death rate • Increased food supplies • Better nutrition • Medical advances – immunization and antibiotics • Safe water and sanitation

10. Migration Immigration –movement in Emigration – movement out • Why move???? • Jobs, economic improvements • Religious persecution • Ethnic conflicts • Wars • Environmental degradations (water shortage, erosion etc…)

11. Since 1820, the U.S. has admitted twice as many immigrants and refugees as all others combined. • Prior to 1960 – most immigrants came from Europe • After 1960 – most come from Latin America and Asia • Large push to reduce immigration • One Reason – to reduce the nations enormous environmental problems

12. Age Structure • Age structure – distribution of males and females in each age group in the worlds population • Age structure graphs can have a rapid, slow, zero, and negative growth rate

13. Expanding, Stable, Declining

16. 29 % of world population is 15 or younger • More in developing countries than developed countries • This high level of youth fuels rapid population growth • The larger population of youth, the larger the adult population will be in the future • This puts a strain on resources • Example – Rwanda 1950 -1993 – population tripled • Demand for fire wood, lead to burning of crops, lose of soil fertility, to less food

17. 1994 – President killed in plane crash • One ethnic group (Hutus) killed an est. 800,000 (Tutsi) in 100 days.

18. Rapid population decline is also bad. • Leads to economic and social problems • Lose of workers for jobs and revenue from spending which has an effect on the economy • This may also divide people

19. Solutions 1. Demographic transition – a hypothetical change in population • As countries become industrialized, death rates, then birth rates drop 2. Family Planning – educational and clinical services that help potential parents • Help with birth control, birth spacing, and health care

20. This prevents unplanned births and also abortions 3. Empowering women • 3 keys • Education • Paying jobs outside of the home • No suppression of rights

21. FACTS • Women make up half of the world population • Account for 2/3 of all hours worked • Receive only 10% of worlds income • Own less than 2% of the land • Make up 70% of the poor • Make up 60% of worlds illiterate adults

22. Urban Sprawl • When growth of low density development on the edges of cities and towns gobbles up the surrounding country side Example – Las Vegas, 1970-2004, population increased from 463,000 to 2 million and rising

24. Problem with Urban Sprawl • Loss of cropland, forests, wetlands • Increased soil erosion • Increased road kill • Weight gain • Air and water pollution • Increased runoff • Increased use of water and resources • Global warming • Increased flooding • Increased crime

26. U.S. Population • Approximately 316,000,000 people • U.S. makes up 4.5% of the world population, uses 25% of world resources, and creates 25% of the world waste • 1790 – first census taken in the U.S. • Projected population in 2025 – 349,000,000 • 2.1 lifetime births per women

27. 5 most populous cities in the U.S. • New York City • Los Angeles • Chicago • Houston • Philadelphia

29. U.S. Life Expectancy • In the U.S. – 78 yrs of age • From 1970 to 2013 life expectancy rose from 70 yrs to 78 yrs. • Currently –Women – 80 yrs Men – 75 yrs

30. Case Study : CHINA Between 1972 and 2000 reduced birthrate from 5.7 to 1.8 HOW : instituted a “one child policy” that gave incentives such as: Extra food Larger pension, salary bonuses Better housing Free health care and school tuition

31. Problems Increased forced abortions Female infanticide Sex imbalance in the country