Occurs when individuals in a population reproduce at a constant rate Causes: Ideal conditions with unlimited resources.

Occurs when individuals in a population reproduce at a constant rate

Causes:• Ideal conditions with unlimited resources

Populations growth slows or stops following a period of exponential growth

Causes:• Birth rate decrease, Death rate increases• Birth rate and death rate are equal• Rate of immigration decreases• Rate of emigration increases

Factor that causes population growth to decrease

Competition Predation Parasitism and disease Drought and climate extremes

• Human disturbances

Density Dependent Factors: Limiting factor that depends on population size

Density Independent Factors: not dependent on population size

Competition• Overcrowding causes organisms to compete

for food, water, space and sunlight Predation

• Predator-prey relationship Parasitism and Disease

• Parasites take nutrients from host, weakening host, spreading disease or death

Affects all populations in similar ways, regardless of population size• Unusual weather• Natural disasters• Seasonal cycles• Human activities