Heimler topic 2.3 Population Composition and Pyramids

Population Composition

• Population composition delves into the demographic makeup of populations, focusing primarily on age and sex.

Demographics

• Demographics encompass distinct traits within a population, such as ethnicity, education level, and income.

Age Structure

• Age structure refers to the organization of a population based on age groups, known as cohorts.
• Analyzing age cohorts helps geographers understand whether a population is growing, stable, or declining.

Dependency Ratio

• Dependency ratio is calculated as the number of dependents (those under 15 or over 65) divided by the number of working-age people (15-65), multiplied by 100: Dependency Ratio = \frac{\text{Number of Dependents}}{\text{Number of Working-Age People}} \times 100
• Example:
  • A country with a population of 75,000,000 has 30,000,000 people younger than 15 and 5,000,000 older than 65.
  • This leaves 40,000,000 in the working-age cohort.
  • Dependency Ratio = \frac{30,000,000 + 5,000,000}{40,000,000} \times 100 = 87.5 %
• A higher dependency ratio indicates a greater burden on the working population to support dependents, while a lower ratio indicates less pressure.

Sex Ratio

• Sex ratio compares the number of males to females in a population.

• It can reveal insights into gender equality or birth rates.

• Sex ratios vary by scale:

  • Globally: approximately 101 men to 100 women.
  • Europe: approximately 95 men to 100 women.
  • China: approximately 105 men to 100 women.

China's One-Child Policy

• Implemented in the 1970s to address rapid population growth and resource concerns.
• Led to a preference for male children, resulting in abortions or abandonment of female children.
• Caused a severely unbalanced sex ratio.
• Although the policy has been rolled back, balancing the ratio will take time.

Population Pyramids

• Population pyramids are key tools for analyzing population composition.
• The y-axis plots five-year age cohorts.
• The x-axis represents the sex ratio.

Four Typical Pyramid Shapes

Rapid Growth

• Wide base and narrow top.
• Indicates a high birth rate and shorter lifespan.
• Common in developing countries.
• Example: Democratic Republic of the Congo.
• Challenges include providing for the needs of a large young population (food, education, etc.).

Slow Growth

• Birth rate is slightly higher than the death rate.
• The population is still growing, but not as rapidly as in rapid growth populations
• Narrow base.
• Example: China (partially due to the One-Child Policy).
• Challenges include providing healthcare for an aging population.

Stable Growth

• Similar birth and death rates.
• Even distribution throughout age ranges.
• Near-zero population growth.
• Example: United States.

Declining Population

• Narrower base than the top.
• Declining birth rate and longer lifespans.
• Example: Germany.
• Challenges include labor shortages due to more people retiring than entering the workforce.