Population Dynamics

Introduction

Population growth rates have fallen from 2.1% per year to 1.95% per year. Where ever you are in the world, population growth is produced by two proocesses - natural change and migration change. (Below)

Natural change

If there are more births than deaths, population will increase.If there are less births than deaths, population will decrease.

Migration change

Migration is the movement of people in and out of an area or country. If immigrants (incomers) exceed emigrants (outgoers), there will be a gain in population. If the situation is reversed, there will be a decrease in population.

Only natural change can result in a change of the Global Population

A whole range of factors has contributed to the fall in morality. They include:

• The development of modern medicines
• The intorduction of vaccination and immunisation programmes
• Better healthcare - more doctors, nurses and hospitals
• More hygienic housing
• Cleaner drinking water and better sewage disposal
• Better diet

Demographic transition model

As a country develops, their birth rate and death rate change and ,as a result, so does their rate of natural change. (below)

The demographic transition model suggests that countries pass through 5 different stages:

Stage 1: High fluctuating - A period of high birth and death rates, both of which fluctuate. Natural change hovers between increase and decrease. Reasons for high birth rate includes:

• Little or no birth control
• High infant morality (death) rate
• Children are seen as an asset…