Population Distribution :
Population Distribution Distribution is based on the availability of natural resources required by a population.
Natural resources include the biotic (living) and abiotic (nonliving) factors in the environment
Slide 3:
3 types of distribution: Clumped, Uniform, Random
Clumped – resources are concentrated in certain areas
Uniform – resources are spread evenly; competition between organisms for resources
Random – resources are abundant and spread evenly; proximity is not an issue for members of the population.
Population Density & Size :
Population Density & Size Population Density = Population Size Geographic Area
Population Size affected by:
Natality (births)
Mortality (deaths)
Immigration (organisms coming in)
Emigration (organisms leaving)
Open Population – affected by immigration/emigration
Closed Population – immigration/emigration not possible
Population Growth :
Population Growth 4 phases
Lag Phase – Organisms getting used to environment; natality low
Growth Phase – Population grows rapidly; high natality/immigration & low mortality/emigration
Stationary Phase – Population has reached carrying capacity (maximum that environment can support)
Death Phase – Environment can’t support population; mortality/emigration higher than natality/immigration
Factors Affecting Population Growth :
Factors Affecting Population Growth Density-Dependent Factors
Occur when populations become too large
Density-Independent Factors
Can happen no matter what size the population is