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Human population


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Human population

  1. 1. Human Population Ch 5.
  2. 2. How has human populationgrown? Slowly over time  Scarce food and incurable disease  Death rate high  Families had many childern 500 years ago  Rapid growth  Why?  Agriculture, industrial; revolution, better food supply, shipping methods improved, improved sanitation, healthcare, improved medicine  Led to expanded human growth
  3. 3. Science Behind HumanPopulation Thomas Malthus  English Economist  Human population cannont grow exponentially  Limits: Famine, disease, war
  4. 4. Demography Scientific study of human population Study a variety of social and economic factors that effect human population Examines characteristics of human population and attempts to explain how and why human population changes over time
  5. 5.  Things that help predict different population growth rates  Birth rate  Death rate  Age structure
  6. 6. Hypothesis These countries have completed a “demographic transition”, a dramatic change in birth and death rates  Historically: humans have high birth and death rates  500 years ago a change began: High birth rate and LOW death rate  Because of better conditions of living
  7. 7. Demographic Transition Dramatic change in birth rates and death rates Low Death rate, High Birth rate  From 1760 to 1910 Society modernizes  Increase level of education  Raise standars of living  Families have fewer children Birth rate decreases Population growth slows Demographic transition complete when:  Birth rate falls to meet death rate and population growth stops  Only complete in a few countries  India and China high birth rate
  8. 8. Age Structure Population depends partly on how many people of different ages make up a population Age-structure diagrams  Population profiles used to predict future population growth  Show population of a country broken down by gender and age group
  9. 9. Age structure in US Equal # of people in each age group Slow and steady growth rate for near future Age Structure in Nigeria• More young children than teenagers• More teenagers than adults• Population will double in 30 years
  10. 10. Controlling Human Population India  Compulsory sterilization China  Family planning program  Benefits and bonuses  Forced abortions
  11. 11. Predicting Future Population Growth Many factors  Age structure of countries  Prevalence of life threatening diseases By 2050  9 billion  Growth will level off or decrease if countries growing rapidly go through demographic transition
  12. 12.  Lower growth rate means population growth is slowing by it is STILL growing How does this effect environment?  Ecologists predict that if this growth does not slow even more there will be Serious damage to  Environment  Global economy  Other ecologists predict that science, technology, and changes in society will control those negative impacts on economy and environment