DEMOGRAPHIC TRANSITION THEORY OF POPULATION. The theory of demographic transition theory is the latest attempt made to provide a historical analysis into the population problems of developing countries.
It tends to explain the reasons why all developed countries several years ago went through three identical stages of population history.
The demographic transition theory puts up a model which recognizes three main stages in the process of population growth or demographic transition.
The three stages are:
Stage I: The pre-industrialization stage
The main feature of this stage is high birth rate and high death rate. The population at this stage is either static or increasing or decreasing at a very low rate. The population transition remains fairly stable.
Stage II: Transitional stage
This stage is characterized By high birth rate. accompanied by low death rate. This stage leads to high population as a result of a number of factors such as industrialization, urbanization, better diet, higher income and improved medical services.
This stage marks the beginning of demographic transition. Many developing countries are currently at this stage of population growth.
Stage III: Post transitional stage
This stage is characterized by a low birth rate and low death rate. In other words, there is a relatively stable population with an older and larger population. This stage is associated with developed countries.
Criticism against demographic transition
- It is completely wrong to use the theory for general applications as it varies from one country to another.
- Crude birth rate widely used in the theory is not the only way to measure fertility.
- The main causes of decline in population may be different in different countries.
- It fails to predict the levels of birth rate and death rate.
- 153. FUNGAL DISEASES
- PROTOZOAN DISEASES
159. TAPE WORM
160. ROUND WORM OF PIGS
161. LIVER FLUKE
162. ECTO PARASITES