The population of the world is estimated to be nearly 7 billion people. Countries such as China and India are currently the most populated, and the least populated country is Tuvalu. How cultures interact together under extreme conditions may play a factor in population growth and decline, as well as natural causes, such as birth and death.
The birth rate is the number of live births per 1,000 in a year. Birth rates are influenced by various factors, including adequate nutritional intake, the fertility of individual child-bearing females and total fertility rates and attitudes. The use of contraceptives to specifically block unwanted pregnancies affects birth rates, along with government policies toward condom use to prevent diseases. The rate of natural increase is the birth rate minus death rate and is calculated as a percentage.
The death rate is counted per 1,000 in a year. Factors affecting death rates include disease -- both individual and infectious disease. The occurrence of war and advancements in medical technology are also causative factors. Improved health care, adequate nutritional intake and exercise are factors that influence death rates and population growth.
Immigration encompasses pull factors, which are the characteristics of a country that attracts people to want to leave their own country and go to a foreign land and pursue citizenship. A surplus of jobs or other positive factors often cause immigration to a particular country.
Emigration affects a population because it is the number of people leaving a country. This adds to the decline in population. Push factors, like war, lack of employment, famine and other negative factors, make people want to leave their own country.
People who are forced to leave their country are called refugees. Small numbers of refugees leave because of discrimination or political upheaval. Larger numbers of refugees may be seen in the factoring of war, famine and natural disasters such as earthquakes.
Population Growth Rates
The population growth rate is the increase of percentage in a population over a period of time. The population growth rate is calculated by subtracting the number of deaths and emigrants from the number of births and immigrants.