Dynamic biological processes influence population density, dispersion, and demography A population A population –Is a group of individuals of a single species living in the same general area
6 Density and Dispersion Density –Is the number of individuals per unit area or volume Dispersion –Is the pattern of spacing among individuals within the boundaries of the population
7 Density: A dynamic perspective. Determining the density of natural populations –Is possible, but difficult to accomplish In most cases –It is impractical or impossible to count all individuals in a population Density is the result of a dynamic interplay –Between processes that add individuals to a population and those that remove individuals from it Births and immigration add individuals to a population. BirthsImmigration PopuIation size Emigration Deaths Deaths and emigration remove individuals from a population.
8 Patterns of Dispersion Environmental and social factors –Influence the spacing of individuals in a population. –There are three different Patterns of Dispersion Clumped Dispersion Uniform Dispersion Random Dispersion
9 A clumped dispersion –Is one in which individuals aggregate in patches –May be influenced by resource availability and behavior Figure 52.3a (a) Clumped. For many animals, such as these wolves, living in groups increases the effectiveness of hunting, spreads the work of protecting and caring for young, and helps exclude other individuals from their territory.