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