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Black Bear
American Bison
White-tailed Deer
Population range
Some species have a very limited population range, or distribution. Other species have a
vast distribution. A species might not be able to expand its population range because it
cannot survive the abiotic conditions found in the expanded region.
Spatial distribution
The pattern of spacing of a population within an area; one of the primary factors in the
pattern of dispersion for all organisms is the availability of resources such as food.
Population density
The number of organisms per unit area; can be calculated by dividing the number of
organisms in the population by the area the population occupies.
Uniform dispersion
Clumped dispersion
1/~200km
2
4/km
2
10/km
2
Random dispersion
Historic range prior to 1865
Figure 2
Visualizing Population Characteristics
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Module 4 • Population Ecology