PopulationsPopulationsHow they grow and what affects them

Characteristics of a Characteristics of a PopulationPopulationPopulation Density

◦How many organisms in a specific area

Geographic Distribution◦Where is the population located

Growth Rate◦How much is the population

changing

Growth RateGrowth RateFactors that affect the Growth

Rate◦# of births◦# of deaths◦Individuals leaving or entering the

population Immigration: Entering IN to a population Emigration: EXITING a population

Types of GrowthTypes of GrowthExponential

◦J Curve◦Reproduction happens at a constant

rate◦Happens under ideal conditions with

unlimited resources

Types of GrowthTypes of GrowthLogistical

◦S Curve◦Population continues to grow but at

a slower rate◦Happens when resources

become scarce

What did you say?What did you say?Carrying Capacity

◦This is the number of individuals a given environment can sustain for a specific population

Carrying Capacity!

Limiting FactorsLimiting FactorsWhat limits the growth of a

population?◦Density Dependent: Only become

limiting when the population reaches a certain level of density

◦Density Independent: Affect all of the populations in the same way.

Density DependentDensity DependentCompetitionPredationDiseaseParasites

Density IndependentDensity IndependentWeatherNatural disastersHuman Factors

◦Damming Rivers◦Deforestation ◦Controlled Burns

Human Population GrowthHuman Population Growth

World Population VideoWorld Population Video