Population density is a measurement of population per unit area or unit volume. In Biology a population is the collection of inter-breeding organisms of a particular Species; in Sociology It is frequently applied to living organisms, humans in particular. Human beings, humans or man (Origin 1590–1600 L homō man OL hemō the earthly one (see Humus It is a key term used in geology.
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Biological population densities
Population density is a common biological measurement and is more often used by conservationists as a measure than population size. Biological data is Data or Measurements collected from biological sources which is stored or exchanged in a digital form The conservation movement also known as nature conservation is a political social and to some extent scientific movement that seeks to protect natural resources including
Low densities may cause an extinction vortex and lead to further reduced fertility. Extinction vortices are a class of models through which conservation biologists, geneticists and Ecologists can understand the dynamics of and categorize This is called the Allee effect, after W. C. Allee who first identified it. The Allee effect is a phenomenon in Biology characterized by a positive correlation between population density and the per capita Growth rate. Warder Clyde Allee ( June 5, 1885 &ndash March 18, 1955) was an American zoologist and ecologist who taught animal Examples of the causes in low population densities include:
- Increased problems with locating mates
- Increased inbreeding
Different species have different expected densities. Inbreeding is breeding between close Relatives whether plant or animal R-selected species commonly have high population densities, while K-selected species may have lower densities. In Ecology, r/K selection theory relates to the selection of traits which promote success in particular environments In Ecology, r/K selection theory relates to the selection of traits which promote success in particular environments Low densities may be associated with specialised mate location adaptations such as specialised pollinators; as found in the orchid family (Orchidaceae).
Human population density
For humans, population density is the number of people per unit of area (which may include or exclude cultivated or potentially productive area). List of countries and dependencies by Population density in inhabitants/km² Human beings, humans or man (Origin 1590–1600 L homō man OL hemō the earthly one (see Humus Commonly this may be calculated for a county, city, country, another territory, or the entire world. A county is a Land area of Regional Government within a larger State. A city is an Urban area with a large Population and a particular Administrative, Legal, or Historical status In Political geography and International politics, a country is a Political division of a geographical entity Types of administrative and/or political territories include Many types of legally administered territories, each of which is a non-sovereign geographic area EARTH was a short-lived Japanese vocal trio which released 6 singles and 1 album between 2000 and 2001
The world population is 6. The world population is the total number of living Humans on Earth at a given time 6 billion humans, and Earth's area is 510 million square kilometers (200 million square miles). EARTH was a short-lived Japanese vocal trio which released 6 singles and 1 album between 2000 and 2001 Therefore the world-wide human population density is 6. 6 billion / 510 million = 13 per km² (33 per sq mi), or 43 per km² (112 per sq mi) considering that humans live on land, which forms 150 million km² (58 million sq mi) of the earth. This density rises with the population growth. It also includes all continental and island land area, including Antarctica. Since over half of the earth's land mass is desert and high mountains hostile to human habitation, only a fraction of the rest is arable, and population clusters heavily around seaports and fresh water sources, this number by itself significantly understates the level of human crowding. In Geography, arable land (from Latin arare, to Plough) is an agricultural term meaning land that can be used for
Several of the highest-density territories in the world are very large city-states, microstates, micronations, or dependencies. A city-state is a Region controlled exclusively by a City, usually having Sovereignty. A microstate or ministate is a sovereign state having a very small population or very small land area but usually both Micronations &mdash sometimes also referred to as model countries and new country projects &mdash are entities that resemble independent Nations or A dependent territory dependent area or dependency is a territory that does not possess full political Independence or Sovereignty as a These territories share a relatively small area and an exceptionally high urbanization level, with an economically specialized city population drawing also on rural resources outside the area, illustrating the difference between high population density and overpopulation. Urbanizationn (also spelled urbanisation) is the physical growth of Urban areas into rural or natural land as a result of population in-migration to an existing A city is an Urban area with a large Population and a particular Administrative, Legal, or Historical status Overpopulation refers to a condition where an Organism 's numbers exceed the Carrying capacity of its Habitat.
Cities with exceptionally high population densities are often considered to be overpopulated, though the extent to which this is the case depends on factors like quality of housing and infrastructure or access to resources. Most of the largest densely-populated cities are in southern and eastern Asia, though Cairo and Lagos in Africa also fall into the category. Cairo () which means "the Vanquisher" or "the Triumphant" is the capital and largest city of Egypt. Lagos ( pron ˈleɪgɒs or /ˈlɑːgoʊs/ overseas is the most populous Conurbation in Nigeria with City population is however, heavily dependent on the definition used for the urban area: densities will be far higher for the central municipality than when more recently-developed and as yet administratively unincorporated suburbs are included, as in the concepts of agglomeration or metropolitan area, the latter including sometimes neighbouring cities. In the study of human settlements an agglomeration is an extended City or Town area comprising the built-up area of a central place ( usually a Municipality A metropolitan area is a large population center consisting of a large Metropolis and its adjacent zone of influence or of more than one closely adjoining neighboring central
Other methods of measurement
While the arithmetic density is the most common way of measuring population density, several other methods have been developed which aim to provide a more accurate measure of population density over a specific area.
- Arithmetic density: The total number of peoples / area of land measured in km² or mi².
- Physiological density: The total population / the amount of arable land.
- Agricultural density: The total rural population / amount of agricultural land.
- Residential density : The number of people living in an urban area / the area of residential land.
- Urban density : The number of peoples inhabiting an urban area / the total area of urban land. Urban density is a term used in Urban planning and Urban design to refer to the number of people inhabiting a given urbanized area
- Ecological optimum: The density of population which can be supported by the area's natural resources.
See also
- List of countries by population density
- List of countries by population
- List of religious populations
- List of U.S. states by population density
- Human geography
- Idealised population
- Optimum population
- Population bottleneck
- Population genetics
- Population health
- Population momentum
- Population pyramid
- Small population size
External links
- City Ranks combines Google Maps and 2000 Census data to show the population densities of U. List of countries and dependencies by Population density in inhabitants/km² List of countries by population in 2005|List of countries by population in 1907This is a list of countries ordered according to Population. Religious demographics and Religions by country. Four largest religions This article is a list of the 50 US States ordered by Population density. Human geography is a branch of Geography that focuses on the study of patterns and processes that shape human interaction with the environment with particular reference to main article Effective population size In Population genetics an idealised population, also sometimes called a Fisher-Wright population The Optimum population for a region or country is a level of (human population which is ecologically Sustainable. A population bottleneck (or genetic bottleneck) is an Evolutionary event in which a significant percentage of a population or species is killed or otherwise prevented Population genetics is the study of the Allele frequency distribution and change under the influence of the four evolutionary forces Natural selection, Genetic Population health is an approach to Health that aims to improve the health of an entire population Population momentum is an effect which causes Population growth. A population pyramid, also called age-sex pyramid and age structure diagram, is a graphical illustration that shows the distribution of various age groups in a Populations with small population size behave differently to larger populations S. zip codes on an interactive map.
- Selected Current and Historic City, Ward & Neighborhood Densities
- Population density world-map
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