Some occupations are more risky and creates so many health problems. Some industries are clinked with various diseases. Death rate in some occupations is high while low in others. For example; death rate is high in workers who are working in the mines and chemical industries. Occupation provides income and standard of living which influence death rate.
Population change has been defined in terms of mortality, fertility and migration. According to the United Nations, mortality is the percentage of death in the population. Death has been defined by WHO, death is the permanent disappearance of all evidence of life at any time after birth has taken place. This definition proves that death can occur only after live birth.
Human migration is the movement of people from one place to another and the intentions of settling to the new location can either be permanent or temporary. This type of movement usually covers a long distance, probably from one country to another. Nomadic movements are not considered as migration as their intention is not to settle in any new place but it’s all seasonal.
important problem of population are given by Warren S. Thompson as under. 1. What are the changes `that takes place in the size of population and how are these changes brought about? 2. Where the people found and what are the changes taking place in their distribution in communities and other areas?
Demography and population studies are the same. The study of human population is known as population studies or demography literally speaking, demography is the combination of two Greek words “Demo” means people and “graphy” means to write or draw. So, it is the science of population. Population studies is concerned with the whole study of population.
There are three main sources of social change i.e. 1. Cultural base 2. Change in population structure and 3. The extraordinary gifted persons