By Dr. Sengupta, CJD International School, Braunschweig Some important terms and Concepts in population dynamics DEMOGRAPHY- is the study of population Population Density Population per unit of land area; that is the number of people per square mile or people per square kilometer. Birth Rate (or Crude birth rate) the number of live births per 1,000 people in a population of a given year. General Fertility Rate (Total fertility rate or TFR) the average number of live births per 1,000 women of childbearing age (14-49 years) in a given year. Death Rate (or Crude death rate) the number of deaths per 1,000 people in a population of a given year. Rate of Natural change - the difference between birthrate and death rate. Growth Rate The number of people added to (or subtracted from) a population in a year due to natural increase and net migration expressed as a percentage of the population Sex ratio- the number of males per 100 females in a population Morbidity - the frequency of disease, illness, injuries, and disabilities in a population. Mortality -deaths as a component of population change. Infant Mortality Rate- the number of deaths of infants under age 1 per 1,000 live births in a given year. Child mortality rate- the number of deaths of children under 5 years of age per 1000 children in a given year. Childbearing Years The reproductive age span of women, assumed for statistical purposes to be 15-49 years of age. Fecundity The physiological capacity of a woman to produce a child. Child-Woman Ratio The number of children under age 5 per 1,000 women aged 15-49 in a population in a given year. Life expectancy- average number of years that a person can be expected to live, usually from birth if other demographic factors remain unchanged. Dependency Ratio The ratio of the economically dependent part of the population to the productive part; arbitrarily defined as the ratio of the elderly (ages 65 and older) plus the young (under age 15) to the population in the working ages (ages 15-64).
Older dependency ration (ODR)- the number of people aged 65 and above for every 100 people aged 20-64 (working population). Demographic Transition The historical shift of birth and death rates from high to low levels in a population. The Demographic Transition Model was developed by the American demographer Warren Thompson in 1929. DTM depicts the demographic history of a country. It refers to the transition from high birth and death rates to low birth and death rates as a country develops from a pre-industrial to an industrializedd system. Migration: the movement of people involving a change of residence. It can be internal displacement or international and voluntary or forced. It is usually for an extended period
(more than a year) and does not include temporary circulation such as commuting or tourism. Emigration The process of leaving one country to take up permanent or semi-permanent residence in another. Brain Drain The emigration of a significant proportion of a country's highly skilled, highly educated professional population, usually to other countries offering better economic and social opportunity. Remittances: transfer of money or goods by foreign workers to their home country. Refugee- a person fleeing their home country in order to escape danger. Asylum seekers- people who seek refugee status in another country. Illegal immigrants- people who enter another country without permission to remain there. Internally displaced persons or people (IDPs)- those who have fled their homes but continue to live in their own country. Doubling Time The number of years required for the population of an area to double its present size, given the current rate of population growth. The world population doubled between 1650-1850 and 1850-1920 and 1920-1970. Thus it is taking less time the population to double (accelerating rate of growth). 95% of the population growth is taking place in developing countries. However, the world population is expected to stabilize by 2050. The slowdown in population growth would be due to decline in fertility and an increase in the number of elderly people. Population momentum- is the tendency for a population to grow despite a fall in fertility level. On the other hand, it also includes the tendency for a population to continue to fall despite a rise in birth rate. Despite the decline in overall population growth rate, the absolute size of the human population will continue to increase over the next several decades because of population momentum. Currently nearly one third of the world s population is under 15 years of age and therefore has not yet reached childbearing age. Because this demographic group is so large in absolute numbers, even if each woman has fewer children than in the past, there will still be a significant increase in global population over the next several decades. Most of the population growth over the next several decades is expected to occur in developing countries, where growth rates are generally higher than for developed countries. The United States is an exception, with one of the most rapidly growing populations of any developed nation Depopulation The state of population decline. Urbanization Growth in the proportion of a population living in urban areas. Pronatalist Policy: The policy of a government, society, or social group to increase population growth by attempting to raise the number of births.
Antinatalist Policy The policy of a government, society, or social group to slow population growth by attempting to limit the number of births. Optimum population is the number of people which when working with all available resources and technology, will produce the highest per capita economic return and highest standard of living and life quality can be attained. Theoretically, if the size of population increases or decreases from the optimum, the standard of living will fall. Optimum population signifies the carrying capacity of a region or country. Overpopulation occurs when there are too many people relative to resource and technology. It is not possible to maintain an adequate standard of living if over population occurs. Human overpopulation occurs if the number of people exceeds the carrying capacity of the region characterized by low income, poverty, poor living condition and high level of emigration. Many countries in sub-saharan Africa are said to be overpopulated because they have insufficient food and energy resources to sustain themselves. They suffer from natural disaster like drought, famine and are characterized by very poor standard of living. Under population occurs when there are far more resources available in an area under the prevailing technology than that are used by the people living there. However the main problems of under population are Threshold population for economic scale operation cannot be attained as it may lead to labour shortage and large scale immigration of foreign workers to cover up the gap in labour market. It may also cause rural depopulation (young generation migrates to urban areas living the old behind). Under population may take the form of imbalanced demographic structure through the decline of replacement population, increase in ageing population and disrupted family structure which will finally lead to possible decline in standard of living. Over, optimum and under population are dynamic concepts, change with time and space as technology improves, population changes and new discoveries and innovation take place enhancing human capacity to resource utilization. Important Data to remember: The current world population is 7 billion. The People's Republic of China, is the most populous country in the world today. The current 2014 estimate is 1,392,472,656. India, the next largest country, has 120 million fewer people, for a population of 1,272,904,150. The United States, the third largest country in the world, has a much smaller population of 323 million. Estimates show that India will surpass China as the most populous nation in the world by 2025. (Ranks: China-India- USA- Indonesia- Brazil) The population of EU-28 countries 505 million in 2013 (Euro stat data). Germany with 80 million people in 2013 is the most populous country in EU. It took all of human history up to the early 1800s for world population to reach 1 billion people, and until 1960 to reach 3 billion. Today, the world gains 1 billion people every 11 years. Population growth rates have been dropping in all regions of the world since the
1970 s, and this trend is predicted to continue. Current expectations are that the human population will level off at about 8.9 billion people by 2050, and stabilize or slowly decline thereafter. Factors affecting population distribution Physical Factors Relief Reasons for areas of High Density Lowland area which is flat or gently sloping terrain such as river plains. Ex. Ganges river. Reasons for areas of low Density Mountainous areas with high altitude and steep slopes. Cold, rare vegetation and frozen soil. For example in Alps, Andes, Himalayas etc. Climate Soil Moderate climates with no extremes. Enough rain and warm temperatures to allow crop growth. Thick fertile soils such as loam and alluvium. South-east England. Extreme climates very cold, very hot. Ex. tundra, Sahara. Thin, rocky and acid soils. ex. Deserts, mountains Vegetation Areas of open woodland and grassland. Very dense jungle. ex. Amazon Basin
Accessibility Coastal areas with easy access. Interior areas with poor access. ex. landlocked countries. Resources Water, timber, minerals such as coal, oil, copper, fishing and so on. ex. Europe Few economic resources. ex.sahel region in Africa or better Savannah. Human factors of population distribution Human Factors Economic Reasons for areas of High population density Large rich markets. Good infrastructure Access to markets Skilled labour force Education and good health facilities Reasons for areas of low population density Poor trading and markets links poor infrastructure Limited work opportunities Social Some groups of people prefer to live next to each other for security and companionship. More isolated people Scandinavia Political Stable government Democratic System Commercial economic system Free market Unstable governments Civil war Political Instability
Interpreting Population Pyramid
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