Human Population

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Human Population

• Unit 5
• Environmental Science 1

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Exponential Growth

• Characterized by doubling
• Starts slowly, but rapidly increases
• Total growth in one doubling is more than the
  total of all preceding growth
• Exponential growth occurs when the rate of growth
  is directly proportional to the number present
• ?N/?t N

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Exponential Growth

• Doubling time equation is
• Doubling time 70/ of annual growth (r)
• So if the annual growth rate is 2 then 70/235
  years to double the population

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Human Population

• A group of organisms living in a group is called
  a population
• Population growth leads to an increase in food,
  energy, pollution and other resource consumption
• Energy is a major concern as the population grown

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Human Population

• Carrying capacity is the maximum population Earth
  can reasonably sustain an average standard of
  living
• In the beginning of history the world population
  has changed very little because the death rate
  and birth rate were relatively equal
• However, recently the birth rate began to out
  number the death rater?
• Why?

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Human Population
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Human Populations

• Changes in population size are recorded and
  monitored by demographers
• Demographers use the numerical equation to
  express changes in the population
• Population growth Birth rate death rate
• This does not take into consideration immigration
  and emigration

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Human Populations
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Developed vs. Developing Countries

• Developed countries are technologically advanced
  and have a high standard of living
• Developing countries have a low standard of
  living
• Developed countries tend to have a lower growth
  rate because of better education and health care
• Developing countries have higher birth and death
  rates

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Developed vs. Developing Countries
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Developed vs. Developing Countries
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Developed vs. Developing Countries
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World Population Trends

• In 2000 the population surpassed 6 billion
• The population has reached 7 billion as of 2011
• The current growth rate is about 1.3 with a
  doubling time of about 54 years

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World Population Trends

• 98 of the growth is occurring in developing
  countries
• The growth rate has slowed since 1965 why?

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World Population Trends

• It is predicted that the worlds population will
  stabilize at 10.2 billion by 2100 and the
  replacement level of 2 children per couple will
  be reached by 2035
• However, some say the population will not
  stabilize until 11.2 billion

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World Population Trends

• How did they come up with this data?
• Declining importance of children needed for labor
• Increased cost of raising children
• Improved social status of women
• Rising education level and improved employment