Environmental Science: Human Population Change and the Environment

ch.7

India's Population Pressures

  • Average children per woman: 4.7 (1980) to 2.3 (2015)

  • Second most populous country (after China)

  • Family planning and education efforts ongoing

  • Population pressure links to environmental degradation

  • Over 20% live under poverty line (<$2/day)

Population Ecology

  • Population: individuals of a species in an area.

  • Population Ecology: studies population size changes due to competition, disease, predation, etc.

Population Size Dynamics

  • Growth Rate (r): defined as $r = b - d$ (birth rate - death rate).

  • Conditions:

    • $r > 0$ : population increases (b > d)

    • $r < 0$ : population decreases (d > b)

    • $r = 0$ : stable population (b = d)

Dispersal

  • Movement of individuals affects populations:

    • Immigration (i) increases size

    • Emigration (e) decreases size

  • Overall growth rate: $r = (b - d) + (i - e)$.

Maximum Population Growth

  • Biotic Potential: maximum growth rate under ideal conditions.

  • Exponential Growth: occurs when conditions are optimal; generates a J-shaped curve.

Environmental Resistance and Carrying Capacity

  • Carrying Capacity (K): maximum sustainable population size.

  • Growth slows as environmental resistance increases, stabilizing around $K$.

Human Population Patterns

  • Human growth influenced by reduced death rates due to health advances (food, medical, sanitation).

  • Growth rate declined: r = 2.2% (1960) to r = 1.2% (2010).

Demographics of Countries

  • Classification: Highly developed vs. developing based on growth rates and industrialization

  • Highly Developed: low birth rates, higher GNI PPP.

  • Developing Countries: higher birth rates, lower GNI PPP, high infant mortality.

The Demographic Transition

  • Stages: Preindustrial, Transitional, Industrial, Postindustrial.

Age Structure of Countries

  • Analyzes age distribution; helps predict growth (pre-reproductive, reproductive, post-reproductive groups).

Culture and Fertility

  • Cultural values influence total fertility rates; high TFRs observed to offset high infant mortality.

Women’s Status and TFR

  • Low socioeconomic status contributes to high TFRs; education crucial for reducing fertility.

Urbanization

  • Urbanization process impacts demographics, resource use, and environmental pressures.

  • Trends indicate an increasing urban population, with significant challenges in developing nations.