Population & Migration Key Concepts

Population Density

  • Arithmetic Density:
    • Definition: Number of people per unit of land.
    • Example: 100 people per square mile.
  • Physiological Density:
    • Definition: Number of people per unit of arable (farmable) land.
    • Significance: High physiological density indicates greater pressure on farmland to produce enough food.
  • Agricultural Density:
    • Definition: Number of farmers per unit of arable land.
    • Significance: High agricultural density often suggests less advanced farming technology, as more farmers are needed to cultivate the same amount of land.

Population Distribution

  • Definition: The pattern of where people live.
  • Factors affecting population distribution:
    • Climate:
      • Fewer people tend to live in extreme climates such as deserts or very cold regions.
    • Water:
      • More people tend to live near sources of fresh water, such as rivers or coasts.
    • Jobs:
      • Cities, serving as economic hubs, attract people due to the concentration of job opportunities.

Population Growth

  • CBR (Crude Birth Rate):
    • Definition: Number of births per 1,000 people per year.
  • CDR (Crude Death Rate):
    • Definition: Number of deaths per 1,000 people per year.
  • NIR (Natural Increase Rate):
    • Definition: The rate of population growth without considering migration.
    • Formula: NIR = CBR - CDR
  • TFR (Total Fertility Rate):
    • Definition: Average number of babies per woman during her reproductive years.

Demographic Transition Model (DTM)

  • Definition: A model that shows how birth and death rates change as countries develop over time.
  • Stage 1:
    • Characteristics: High birth rates and high death rates.
    • Growth: Low population growth.
    • Description: Pre-industrial societies.
  • Stage 2:
    • Characteristics: High birth rates but declining death rates.
    • Growth: Rapid population growth.
    • Description: Typically developing countries.
  • Stage 3:
    • Characteristics: Falling birth rates and low death rates.
    • Growth: Slower population growth.
    • Description: Industrializing countries.
  • Stage 4:
    • Characteristics: Low birth rates and low death rates.
    • Growth: Stable population.
    • Description: Developed countries.
  • Stage 5 (Possible):
    • Characteristics: Very low birth rates and low death rates.
    • Growth: Population decline.
    • Description: Some highly developed countries.

Population Pyramids

  • Definition: Graphs that display the age and gender structure of a population.
  • Wide base:
    • Indication: A large proportion of young people in the population.
    • Implication: Fast population growth.
  • Narrow base:
    • Indication: A smaller proportion of young people in the population.
    • Implication: An aging population, potentially leading to slower growth or decline.

Population Policies

  • Pro-natalist Policies:
    • Definition: Policies that encourage births.
    • Example: Paid maternity leave in France.
  • Anti-natalist Policies:
    • Definition: Policies that aim to limit births.
    • Example: China’s former one-child policy.

Migration

  • Push Factors:
    • Definition: Factors that compel people to leave their homes.
    • Examples: War, poverty, natural disasters.
  • Pull Factors:
    • Definition: Factors that attract people to new locations.
    • Examples: Job opportunities, safety, educational prospects.

Types of Migration

  • Voluntary Migration:
    • Definition: Migration based on personal choice and free will.
  • Forced Migration:
    • Definition: Migration where individuals have no choice but to move.
    • Examples: Slavery, displacement due to conflict (refugees).
  • Internal Migration:
    • Definition: Migration within the borders of a single country.
    • Example: Movement from rural to urban areas.
  • International Migration:
    • Definition: Migration between different countries.

Migration Models

  • Ravenstein’s Laws of Migration:
    • Key Principles:
      • Most migrants move over short distances.
      • Migrants traveling long distances tend to move to large cities.
      • The majority of migrants are young adults.
  • Gravity Model:
    • Principle: Larger and closer places tend to attract more migrants compared to smaller and more distant places.

Migration Patterns

  • Guest Workers:
    • Definition: Temporary workers who migrate to foreign countries for employment.
  • Remittances:
    • Definition: Money sent back home by migrants to their families or communities.
  • Brain Drain:
    • Definition: The emigration of highly skilled or educated individuals from their home country, leading to a loss of talent and expertise.