Population Ecology Notes:
Biotic Potential: Genetically determined maximum reproductive rate for a species under ideal conditions.
• Examples:
• Whales and humans have low biotic potential
• Rabbits and bacteria have high biotic potential
*These do not change*
Environmental Resistance: Collective factors that reduce ideal population growth
• Types:
• Density Dependent- depends on the size of the population
• Ex. Disease, predation, competition
• Density Independent- Factors that limit a population growth regardless of size
• Ex. Climate, natural disasters
Carrying Capacity: Maximum population size that a particular environment can support over time.
• Carrying capacity results from the interaction between biotic potential and environmental resistance.
Environmental Resistance
Carrying Capacity
Biotic Potential
Population Growth (2 types)
Exponential growth
 “J Shaped” curve
 Population Increases by the same factor every
year
Logistic Growth
 “S Shape” curve
 Population levels off when it reaches carrying
capacity
 Can over shoot and:
1. Die back to carrying capacity
2. Die back to a lowered carrying capacity
3. Crash to extinction or near extinction
*Which occurs depends on the amount of environmental
damage done during the overshoot*