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Population density is the number of people per unit of area, usually transcribed as "per square kilometer" or square mile, and which may include or exclude, for example, areas of water or glaciers. Commonly this is calculated for a county, city, country, another territory or the entire world. The world's population is around 8,000,000,000 [ 3 ...
Biological dispersal refers to both the movement of individuals (animals, plants, fungi, bacteria, etc.) from their birth site to their breeding site ('natal dispersal'), as well as the movement from one breeding site to another ('breeding dispersal'). Dispersal is also used to describe the movement of propagules such as seeds and spores.
Species distribution, or species dispersion, [1] is the manner in which a biological taxon is spatially arranged. [2] The geographic limits of a particular taxon's distribution is its range, often represented as shaded areas on a map. Patterns of distribution change depending on the scale at which they are viewed, from the arrangement of ...
The Demography of the World Population from 1950 to 2100. Data source: United Nations — World Population Prospects 2017. Demography (from Ancient Greek δῆμος (dêmos) 'people, society' and -γραφία (-graphía) 'writing, drawing, description') [1] is the statistical study of human populations: their size, composition (e.g., ethnic group, age), and how they change through the ...
Based on a dataset of average population density of hunter-gatherer groups collected by Lewis R. Binford, which indicate a mean density of 0.1223 humans per km 2 and a median density of 0.0444 humans per km 2, the combined human population of Africa and Eurasia at the time of the LGM would have been between 2,998,820 and 8,260,262 people.
Population geography. Satellite image of Earth at night. Population geography relates to variations in the distribution, composition, migration, and growth of populations. Population geography involves demography in a geographical perspective. [a] It focuses on the characteristics of population distributions that change in a spatial context.
The three factors affecting edges can be summarized: Abiotic effect—Changes in the environmental conditions that result from the proximity to a structurally dissimilar matrix. Direct biological effects—Changes in species abundance and distribution caused directly by physical conditions near the edge.
Population size. In population genetics and population ecology, population size (usually denoted N) is a countable quantity representing the number of individual organisms in a population. Population size is directly associated with amount of genetic drift, and is the underlying cause of effects like population bottlenecks and the founder ...