Populations

 Characteristics of Populations Geographic Distribution Density Growth rate  Population Growth  Population Growth – an increase in the size of a population over time  Factors that affect population growth  # of Births  # of Deaths  # of individuals that enter or leave  Population Growth Dollars earned  Is not linear… Time in hours  Population Growth  But exponential- as a population gets Population size larger, it also grows faster. Time  Population Growth  Has limits  Limiting factors- cause a population to stop increasingDensity dependent factors have an increasing effect as the population increases  Density Dependent Factors  Disease  Competition for resources-food, water, mates, territories, nesting sites  Predation  Stress  How do increases and decreases in the moose population affect the wolf population? 60 2400 50 2000 40 1600 30 1200 20 800 10 400 0 1955 1960 1965 1970 1975 Moose 1980 Wolves 1985 1990 1995   Density independent factors –affect all populations regardless of density  Temperature  Storms  Floods  Droughts