om diseases. The population momentum is one of the greatest causes of population growth. Population momentum occurs simply because the next reproductive group is starting to have children. When referring to, The State of the World Atlas, by Dan Smith one can observe population patterns. Page 14 shows the population doubling dates, where one can figure out based on the facts given, which stage of the demographic transition each country is in at various times. This also gives insight into how cultural integration plays an important role in population growth and variation. Page 16 in the atlas shows life expectancy across the world. It also states that increases in life expectancy are mainly due to improvements in three basic social conditions: better nutrition, a clean water supply, and access to health services. Consequently, life expectancy is considerably higher in the richer countries than in the poorer parts of the world(16). An example of this can be seen in the article, Gray Dawn: The Global Aging Crisis. The article discusses the aging crisis, which is due to the advancements in technology, which are allowing people to live longer. As discussed in the article the growth of elderly is going to cost lots of money that many people are not planning on. Nutrition is a good indicator into population variations across the world. Countries that naturally have more food available as opposed to poorer countries, who often suffer from malnutrition, find larger populations of healthier people living longer. On the other hand countries who lose babies and children often due to lack of resources often have higher birth rates because the adults in the countries want to have lots of children in case they lose one or more (18-21). Age provides one with an understanding of population growth. Countries where average life expectancies increase and family sizes decline, the proportion of older people in a population increases(24)....
