Definition for Demographic transition
From Biology Forums Dictionary
1. The shift in birth and death rates accompanying human societal development.
2. A demographic transition is a theoretical model of economic and cultural change proposed in the 1940s and 1950s to explain the declining death rates and birth rates that occurred in Western nations as they experienced industrialization. The first stage is a stable pre‑industrial stage of high birth and death rates. The second stage is a transitional stage characterized by declining death rates due to increased food production and improved medical care. Birth rates are still high, as citizens have not yet grown used to the new economic and social conditions, resulting in a surge in population growth. The third stage is the industrial stage. Widespread industrialization creates opportunities for employment outside the home. Children become less of a critical economic asset. Birth rates begin to fall. The last stage is a stable post-industrial stage of low birth and death rates.
All countries do not go through the demographic transition. Transition may be different in developing countries as they industrialize or in countries that place greater value on childbirth or grant women fewer freedoms. Resources may also limit the ability to attain an equal standard of living in all countries. Also, it is now becoming increasingly clear that HIV/AIDS in Africa is causing many nations to slide backwards into what is nearly a pre-industrial society and so do not follow the model for demographic transition.
3. The historical shift of birth and death rates from high to low levels in a population.