Population Growth Curves PDF

Population Growth Curves J-Curve  Rapid exponential growth followed by a sharp decrease in population numbers.  Typical of a closed system (no additional nutrients, waste accumulation)  eg. Insect/mosquito populations Population Number Time S-Cur...

Population Growth Curves J-Curve  Rapid exponential growth followed by a sharp decrease in population numbers.  Typical of a closed system (no additional nutrients, waste accumulation)  eg. Insect/mosquito populations Population Number Time S-Curve  Rapid population growth followed by stability at carrying capacity. Environmental resistance (insufficient water, nutrients, suitable habitat, adverse weather conditions, predators, disease, etc) limits continued growth.  Typical of an open system (continual replenishment of resources and removal or waste). Population Number Time What is occurring during each phase? 1. Lag Phase – low population numbers  Problems finding a mate; acclimatization to new environment. 2. Exponential Growth Phase – excessive resources  Natality >> mortality. 3. Stationary Phase – carrying capacity reached  Limited space, resources, accumulation of waste.  Population number matches resource availability.  Natality = mortality 4. Death Phase – decreases or depleted resources  Natality < mortality