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