ENVIRSC 1C03 Lecture Notes - Lecture 23: Ecological Footprint, Waterborne Diseases, Demographic Transition
Document Summary
The drastic change in the population over the last 200 years can be explained by a few factors. Diseases, epidemics helped to control population size, high infant mortality rate where high birth rates were matched by high death rates. The situation changed in 1830 with the recognition of waterborne diseases. This lead to subsequent major sanitization and hygiene improvements. Introduced vaccinations and the immunization of infectious diseases. A major achievement was the eradication of the smallpox in the 1970s. The 1930"s saw the development of penicillin and the subsequent proliferation of antibiotics. As a consequence of these changes, limits on population growth imposed by infectious diseases were removed. Illustrates within a given population how many people belong to different age groups. In developing countries, most of the population is in the younger age groups. While historically many died before becoming adults now a large number of people are moving into older ages.