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Population - distribution and structure

World population density

Mexico population distribution

Why is population distributed unevenly?

> Accessibility and relative location
> Topography and soil
> Climate and weather
> Water availability and quality
> Resources
> Historical circumstance
> Cultural significance

World Population & Income 1988

World food production

In addition to geographic distribution . . . Demographers also display the structural variation within particular subgroups of a population.

Population pyramids

Population pyramids show a composite of the age and sex of a given population.

Population projections

Population dynamics and processes

How do people enter and leave a given population?

Births and Deaths

> Crude birth and death rates expressed as a ratio per 1000 people.
> Which countries would have a high birth rate?
> Which would have a high death rate?


Total fertility rate (TFR) is the average number of children a woman will have between 15-49 years old.

Natural Increase

Births - deaths = natural increase

Doubling Time

Use the "rule of 72" for calculating doubling time from the rate of natural increase.
Divide 72 by the rate of natural increase to get the number of years it will take for a given population to double. For example, if you want to know how long it will take to double a given population at a four percent rate of natural increase, divide 4 into 72 and get 18 years.

Life expectancy:
The average number of years an infant newborn is expected to live.

Infant mortality
Access to drinking water.

Over 65 year olds

Dependency ratio:
measure of the impact of the young and old on the more economically productive members of the population

Economically active men and women over 60. In some parts of the world, men and women must continue working as senior citizens.

Why do parents choose to have children?

women’s status
family name/bloodline
religious issues
lifestyle/cultural traits
cultural expectations
household economics
child labor
elderly support (social security)
infant mortality
lack of education
personal fulfillment
last rites
marital status
access to contraception
gender selection
government intervention

Examples of geographic context:

 Urban: lack of space - apartment rents are expensive, education and waged work are often available for women.  Rural: kids perform chores, lots of space means cheaper rent, traditional culture: women often don't have waged work.
 More developed countries (MDC) educated workers needed to work in high-tech  Less developed countries (LDC) high infant mortality and no formal system of social security encourage large families so parents have someone to take care of them in their old age. Status of women is often low.