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History of the Human Population

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History of the Human Population In 1838, the ideas of Malthus greatly impressed a young naturalist named Charles Darwin. Malthus s idea that populations tend to ... – PowerPoint PPT presentation

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Title: History of the Human Population


1
History of the Human Population
2
  • In 1838, the ideas of Malthus greatly impressed a
    young naturalist named Charles Darwin. Malthuss
    idea that populations tend to outgrow their
    resources became a major point in Darwins theory
    of evolution by natural selection. According to
    Darwins theory, organisms produce more offspring
    than can survive. Within the population there are
    a variety of traits. Those individuals with the
    most favorable traits will survive and pass those
    traits to their offspring. Over many generations,
    favorable traits accumulate in the population,
    resulting in evolution.

3
  1. Why do many organisms produce more offspring than
    can survive?
  2. According to Darwin, the individuals that survive
    have what?

4
  • Why do many organisms produce more offspring than
    can survive?
  • To ensure survival of a few

5
  • 2. According to Darwin, the individuals that
    survive have what?
  • Favorable traits

6
Thomas Malthus1798
  • Population growth is not always desirable
  • Population increases geometrically
  • 1,2,4,8,16,32
  • Food supply increases arithmetically
  • 1,2,3,4,5
  • Human population increases at a faster rate than
    food supply!!!
  • This could lead to famine and war

7
When will the population remain stable?
  • When birth rate equals death rate!!!!
  • Increased birth rates increase population size
  • Decreased death rate increases population size
  • If both are the same, the population should
    remain stable!!!

8
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9
What was Malthus solution?
  • Reduce population growth rate by
  • Later marriages
  • Small families

10
Hunter-Gatherer
  • Slow population growth
  • Starvation, predation, disease- short lives
  • High infant mortality rate
  • Food storage increase in population size

11
Agriculture
  • Farming communites
  • Increased and steady food supply increase in
    human population
  • Increase in standard of living- reduced mortality
    rates and increased life expectancy

12
Industrial
  • Technological advances- increased food production
    and distribution
  • Safer work environments
  • Improvement in health care- germ theory

13
Germ Theory
  • Bacteria and other microorganisms are responsible
    for many diseases
  • Led to an increase in
  • Sterile surgery
  • Better personal hygiene
  • Water treatment
  • Biomedical Revolution- increase in vaccines and
    antibiotics
  • This all led to an increase in population

14
Declines in Growth Rate
  • Disease bubonic plague reduced Englands
    population by ½
  • Cholera, typhus, yellow fever, smallpox
  • More common in cities
  • Famine- plant diseases
  • Ex potato blight in Ireland
  • War

15
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16
  1. What were Malthuss views about population growth
    vs. food supply growth?
  2. What two rates affect overall population growth?
    Explain.
  3. What event marked the second period of major
    population growth? How did this event influence
    population growth?
  4. What era began about 300 years ago and also
    brought about major population growth? Explain
    how.
  5. What is the germ theory?
  6. How has the germ theory helped to contribute to
    population growth?
  7. What are some contributing factors to declines in
    growth rate?
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