Population Ecology

Population Growth

• Factors that affect population growth are: Age of reproductive maturity, number of offspring produced, frequency of reproduction, and survivorship of offspring to reproductive maturity

• Equation: dN = change in pop size, dt = change in time, B = Birth rate, D = death rate

dN/dt = B - D

Exponential Growth

• Sharp increase in population growth, occurs under ideal conditions w/ abundant resources

• Number of organisms added to each generation increases as the population grows

• More individuals are reproducing but amount of time it takes to produce offspring stays the same

• J CURVE!!

  

Equation: dN = change in pop size, dt = change in time, N = population size, r = maximum per capital growth rate of population

dN/dt = rN

Logistical Growth

• Growth starts slowly, then exponential growth, then stable maximum growth

• Carrying capacity: Max # of individuals envt can support

  

• Equation: dN = change in pop size, dt= change in time, N = pop size, K = carrying capacity, r = max per capital growth rate of pop

  dN/dt = rN((K-N)/K)

  

Factors that limit population growth

• Density-independent factors include natural events such as wildfires, hurricanes, earthquakes, etc.

• Density-dependent factors depend on population density and include things like competition, disease, and predation