PP

Chapter 6: The Human Population and Its Impact

How Many People Can the Earth Support?

Natural Capital Degradation

  • Reduction of biodiversity
  • Increase NPP use
  • Elimination of natural predators
  • Interfering with biochemical cycling
  • Relying on fossil fuels

Human Population Growth Continues but It Is Unevenly Distributed

  • Cultural carrying capacity: the number and type of a given species that people will tolerate over time

What Factors Influence the Size of the Human Population?

The Human Population Can Grow, Decline, or Remain Fairly Stable

  • Population change: (births + immigration) – (deaths + emigration)
  • Crude birth rate: The number of live birth's per 1,000 people in a population in a given year
  • Crude death rate: The number of deaths per 1,000 people in a population in a given year

Women Having Fewer Babies but Not Few Enough to Stabilize the World’s Population

  • Fertility rate: Number of children born to a woman during her lifetime
  • Replacement-level fertility rate: The average number of children a couple must have to replace themselves
    • 2.1 in developed countries
    • up to 2.4 in developing countries
    • Not immediate so many are younger than 15 years old
  • Total Fertility Rate (TFR): The average number of children born to women in a population during their reproductive years.
    • Plays a role in determining population size

Factors That Affect Birth and Fertility Rates

  • Children might be a part of the labor force
  • Cost of raising children
  • Education and employment of women are slowly increasing
  • Availability of abortions
  • Religious or cultural beliefs
  • Availability of birth control

Factors That Affect Death Rates

  • Life expectancy: The average number that an individual is likely to live
    • Global life expectancy from 48 in 1955 to 69 in 2010
  • Infant mortality rate: Number of live births that die in the first year
    • A strong indication of the quality of life in the area
  • Longer lives because…
    • Increased food supply
    • More nutritions
    • Available medical resources
    • Improvements in sanitization

How Does a Population’s Age Structure Affect Its Growth or Decline?

A Population’s Age Structure Helps Us Make Projections

  • Age Structure Categories:

    • Prepreproductive age (0-14)
    • Reproductive ages (15-44)
    • Postreproductive ages (45 and older)

    The 4 different age structure graphs

Some Problems With Rapid Population Decline

  • Threaten economic growth
  • labor shortage
  • Fewer business formations
  • Retirement age increases
  • Pensions can be cut

How Can We Slow Human Population Growth?

As Countries Develop, Their Populations Tend to Grow More Slowly

  • Demographic transition: First death rate declines and then the birth rate declines.
  • Four Stages
    • Preindustrial: The population grows slowly and has a high death and birth rate.
    • Transitional: The population grows rapidly and the birth rate is high. Death rate drops.
    • Industrial: Population growth slows as both birth and death rates drop because of improved food production, health, and education
    • Postindustrial: Population growth levels off and then declines as birth rates equal and the fall below death rates

Women

  • Do most of the housework and care for children
  • Unpaid health care
  • Discriminated against legally and religiously
  • Women make up 64% of the 800 million illiterate adults
    • Illiterate women TFR→ 5-7 Children
    • Literate women TFR→ 2 or fewer children
  • Family Planning: Provides educational and clinical services that help couples choose how many children they want to have and when to have them