Population
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- For the use of the word population in statistics, see statistical population.
In sociology and biology, a population is the collection of people, or organisms of a particular species, living in a given geographic area, or space, usually by census.
In biology, plant and animal populations are studied, in particular, in a branch of ecology known as population biology, and in population genetics. In population dynamics, size, age and sex structure, mortality, reproductive behaviour, and growth of a population are studied. In biology, an isolated population denotes a breeding group whose members breed mostly or solely among themselves, usually as a result of physical isolation, although biologically they could breed with any members of the species. Metapopulation is a group of sub-populations in a given area, where the individuals of the various sub-populations are able to cross uninhabitable areas of the region. Biological dispersal is one of the key elements affecting in such populations.
Demography is the study of human populations. Various aspects of human behavior in populations are studied in sociology, economics, and geography. Study of populations is almost always governed by the laws of probability, and the conclusions of the studies may thus not always be applicable to some individuals. This odd factor may be reduced by statistical means, but such a generalization may be too vague to imply anything. Demography is used extensively in marketing, which relates to economic units, such as retailers, to potential customers. For example, Starbucks, a coffee shop company that wants to sell to a younger audience, looks at the demographics of an area to be able to appeal to this younger audience.
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Population density
- Main article: Population density
Population density is measured by dividing the number of individuals by the area of the region in which they live.
Some observers of human societies believe that the concept of carrying capacity also applies to the human population of the Earth, and that unchecked population growth can result in a "Malthusian catastrophe." Others dispute this view. The graph to the right depicts logistic growth of population.
Populate, as a verb, means the process of populating a geographic area, as by procreation or immigration.
The countries with the highest population density are microstates: Monaco, Singapore, the Vatican City, and Malta. Among larger-sized countries, Japan and Bangladesh have two of the highest population densities.
Population pyramid
The age and gender distribution of a population within a given nation or region is commonly represented by means of a population pyramid. This is a triangular distribution with the portions of the population along the horizontal X-axis and the 5-year age groups (cohorts) along the vertical Y-axis. Male population is shown to the left of the vertical axis and female to the right.
This type of chart displays the development of a population over a period of time. Nations with low infant mortality and high longevity will display a more rectangular shape as a majority of the population living to old age. The converse will have a more pyramidal shape with a wide base, reflecting higher infant mortality and greater risk of early death.
Underpopulation
- Main article: Underpopulation
In biology, a rarely occurring situation in which a group of individuals of a species appear in a new, inhabitable area suitable for more individuals, and begin to populate it. This may also happen if individuals of a species have been transferred to new areas on purpose or by accident. Ecological niches are usually populated, but evolution of a species may enable it to overcome the difficulties encountered in an initially hostile environment.
Under-population occurs when there are far more resources in an area for example, food, energy and minerals than can be used by the number of people living there. Hence, the maximum potential of that area is not realized as the resources are not fully exploited and therefore a high standard of living is not attained. Countries like Canada and Australia can export the surplus of food, energy, and mineral resources, have high incomes, good living conditions and level of technology and immigration. It is probable that standards of living would rise through increased production and exploitation of resources if population were to increase.
However, when making comparisons on a global scale, there does not seem to be any direct correlation between population density and over or under-population. North East Brazil for example is ‘over-populated’ with two people per square kilometer whereas California is ‘under-populated’ with over 500 people per square kilometer (this is therefore related to the number of resources). Similarly, population density is not necessarily related to the GDP per capita. The Netherlands and Germany for example, both have a high GDP per capita and a high population density whereas Canada and Australia have a high GDP per capita and a low population density. Bangladesh on the other end has low GDP per capita and a high population density etc…
The balance of population and resources within a country may be uneven. For example, a country may have a population, which is too great for one resource such as energy, yet too small to use fully a second such as food supply. The relationship between population and resources are highly complex and the terms over and under-population must therefore be used with extreme care.
Population
Some of the indicators of living standard include state of services such as health and education, state of housing, employment, communication networks, trade and commerce, life expectancy, mechanization, level of industrialization etc…
Under-population as a result of de-population
Rural areas surrounding major cities in advanced countries such as the U.K, experience under-population due to outward migration. In the U.K, the South West Wales and the highlands of Scotland are under-populated as compared to the rest of the country. This has also happened in older declining industrial areas and the outward movement or migration has been due to lower wages and unemployment. This result in a decline in a population and with fewer people, there is a decrease in demands for services. The lower level of services therefore encourages further outward migration.
Attempts to tackle under-population
(a) Improving communication networks for example, better transport facilities in order to make remote places more accessible.
(b) Establishment of new capital cities, new towns, or development growth points. For example, Brazil has a population imbalance between the coastal parts from east and south and the rest of the country. Brasilia, the new capital was created in the 1960s in the country's geograpical center to attract people into the North and Center-West regions, but this approach's efectiveness was limited as most of these unpopulated areas is occupied by large forests and swamps. This strategy has also been used in other developing countries such as Nigeria and Tanzania where modern network o railway links has been established though this strategy has not been successful.
(c) Brazil has also adopted comprehensive regional development program. The interior improvement of transport networks and development of secondary growth points and rural development have all been enhanced to attract more people or to discourage out-migration. The standard of living in such regions will therefore gradually improve due to improved resource utilization.
Carrying capacity and the concept of population ceiling
Carrying capacity is the largest number of people that can be adequately supported by a given area of land. The maximum carrying capacity of a population is referred to as a population ceiling, a concept first suggested by Thomas Malthus. Carrying capacity related to available resources and existing level of technology. It indicates the number of people that can be adequately supported by the productive capacity of the land. It is the saturation level where the carrying capacity equals the population and where population equals the carrying capacity of the environment (in other words, the maximum capacity of the environment is called the saturation level). This ecological concept has been applied to sustainable management of the environment. Carrying capacity is more or less similar to optimum population and it is dynamic. It may rise or increase due to economic progress or technological advances or because of the discovery of other resources. Population growth is indeed influenced by resources and it affects the resources available.
Population control
- Main article: Population control
Population control is the practice of curtailing population increase, usually by reducing the birth rate. Surviving records from Ancient Greece document the first known examples of population control. These include the colonization movement, which saw Greek outposts being built across the Mediterranean and Black Sea basins to accommodate the excess population of individual states. An important example of mandated population control is China's one-child policy, in which having more than one child is made extremely unattractive. This has led to allegations that practices like infanticide, forced abortions, and forced sterilization are used as a result of the policy.
In ecology, population control is on occasions considered to be done solely by predators, diseases, parasites, and environmental factors. At many times human effects on animal and plant populations are also considered. See also [1]. Migrations of animals may be seen as a natural way of population control, for the food on land is more abundant on some seasons. The area of the migrations' start is left to reproduce the food supply for large mass of animals next time around. See also immigration.
Population decline
- Main article: Population decline
Population decline is a fall in a region's population. It can be caused by sub-replacement fertility or heavy emigration, or more dramatically disease, famine, or war. Or most often by a combination of the factors. In the past population decline was mostly observed due to disease. In recent years, the population of Russia and seventeen other ex-Communist countries began to decline (1995-2005). The Black Death in Europe or the arrival of Old World diseases to the Americas all caused massive population declines.
In biology, population decline of a species is usually described as a result of gradually worsening environmental factors, such as prolonged drought or loss of inhabitable areas for the studied species. These, or other factors, may lead to a small population, in which case genetical factors may become dominant in the survival, or extinction of a population.
Population transfer
- Main article: Population transfer
biological aspects, see introduced species
Population transfer is a term referring to a policy by which a state forces the movement of a large group of people out of a region, most frequently on the basis of their ethnicity or religion. This has occurred in India and Pakistan, between Turkey and Greece, and in Eastern Europe after the Second World War. Other movements in population are caused by immigration, such as the immigration from Europe to European colonies in the Americas, Africa, Australia and other places.
Population bomb
- Main article: The Population Bomb
A best-selling work, The Population Bomb (1968) by Paul R. Ehrlich predicted disaster for humanity due to overpopulation and the "population explosion". The work used a similar argument to Thomas Malthus's An Essay on the Principle of Population (1798), that population is subject to exponential growth and will outstrip food supply resulting in famine. However, a key difference was Ehrlich's introduction of the Impact formula:
I = PAT (where I=Impact, PAT = Population x Affluence x Technology)
Hence, Ehrlich argues, affluent technological nations have a greater per capita impact than poorer nations.
A "population bomb," as defined in the book, requires three things: a rapid rate of change; a limit of some sort; and delays in perceiving the limit. The book's specific prediction that "in the 1970s and 1980s hundreds of millions of people will starve to death" did not come to pass, however, due for the most part to the efforts of Norman Borlaug's "Green Revolution" of the 1960s.
It was later shown by Keith Greiner (1994) that Ehrlich's projections could not possibly have held the scrutiny of time, because Ehrlich applied the financial compound interest formula to population growth. Using two sets of assumptions based on Ehrlich's hypothesis, it was shown that the theorized wild growth in population and subsequent scarcity of resources could not have occurred on Ehrlich's time schedule.
In 1972 the Club of Rome more or less repeated the argument in Limits to Growth. Liberal thinkers such as Julian Lincoln Simon have also argued that overpopulation is not a legitimate concern. Rather than leading to poverty, Simon in effect argues population is one reason why prosperity exists.
World population
- Main article: World population
According to estimates published by the United States Census Bureau, the world population hit 6.5 billion (6,500,000,000) on February 25th, 2006, at 7:16 p.m. Eastern Standard Time. On October 18th, 2012 at 4:36 p.m. Eastern Daylight Time, the Earth will be home to 7 billion people. The United Nations Population Fund designated October 12, 1999 as the approximate day on which world population reached six billion. This was about 12 years after world population reached five billion, in 1987. However, given that the population of some countries, such as Nigeria, is not even known to the nearest million, such precise timings are essentially meaningless.
Countries by population
- Main article: List of countries by population
About 4 billion of the world's 6.5 billion people live in Asia. Seven of the world's ten largest countries by population are in Asia (although Russia is also located in Europe).
| Rank | Country | Population | Density (people/ km2) |
|---|---|---|---|
| — | World | 6,499,973,414 | 43 |
| 1 | Image:Flag of the People's Republic of China.svg China | 1,313,973,713 | 136 |
| 2 | Image:Flag of India.svg India | 1,095,351,995 | 328 |
| 3 | Image:Flag of the United States.svg United States | 298,540,006 | 30 |
| 4 | Image:Flag of Indonesia.svg Indonesia | 222,781,000 | 126 |
| 5 | Image:Flag of Brazil.svg Brazil | 186,405,000 | 21 |
| 6 | Image:Flag of Pakistan.svg Pakistan | 163,985,373 | 202 |
| 7 | Image:Flag of Bangladesh.svg Bangladesh | 144,319,628 | 1,002 |
| 8 | Image:Flag of Russia.svg Russia | 142,800,000 | 8 |
| 9 | Image:Flag of Nigeria.svg Nigeria | 131,530,000 | 139 |
| 10 | Image:Flag of Japan (bordered).svg Japan | 127,417,244 | 337 |
See also
- Population density
- List of countries by population
- List of religious populations
- List of selected cities by population density
- 1907 populations
- Biological dispersal
- Epidemiology
- Human geography
- Idealised population
- Optimum population
- Population bottleneck
- Population coding
- Population genetics
- Population health
- Population momentum
- Population pyramid
- Small population size
- Stellar population(52)
References
- Proceedings of the United Nations Expert Meeting on World Population to 2300
- Introduction to Social Macrodynamics: Compact Macromodels of the World System Growth by Andrey Korotayev, Artemy Malkov, and Daria Khaltourina. Moscow: URSS, 2006. ISBN 5484004144 [2]
External links
- The Optimum Population Trust. A reliable and intelligent source of population information.
- Phishare.org (2005). Population and Health InfoShare. Retrieved February 13, 2005.
- Population Reference Bureau (2005). Retrieved February 13, 2005.
- Populationworld.com (2005). Population World: Population of World. Retrieved February 13, 2004.
- United Nations (2004). Population Division, Department of Economic and Social Affairs. Retrieved February 13, 2004.
- United States Census Bureau (2005). Census Bureau - Countries Ranked by Population. Retrieved February 13, 2005.
- PopulationData.net (2005). PopulationData.net - Informations and maps about populations around the world. Retrieved March 4, 2005.
- World Population Clock (French) WorldPopClock.com - World population clock.
- World Population Clock (English) - US Census
- Current Resident Population of U.S. - Gadberry Group
