1. Population Growth Exponential growth:
The total number of individuals increases as the number of reproducing females in the population increases.
Shows a “J” shaped (exponential) curve
Population (numbers of individuals)
Exponential growth phase
Growth accelerating.
Lag phase
Growth is slow due to small population size.
Generations

2. Environmental Limits on Population Growth
Logistic growth:
Populations are dependent upon finite resources for survival.
This will limit the exponential growth phase of a population curve
Shows an “S” shaped (sigmoidal) curve
Equilibrium phase
Deceleration phase
Carrying capacity (K)
-The total number of individuals an environment can hold.
Exponential growth phase
Population (numbers of individuals)
Lag phase
Generations

3. r and k strategists r- strategist k- strategist
Population (numbers of individuals)
r- strategist
k- strategist
Generations

4. r and k strategists r-strategists k-strategists
Populations never move from the “r” phase of the growth curve.
Produce far more offspring than will survive
Population never reaches “reproductive potential.”
Give no care to offspring
Population is controlled by density independent factors (i.e. climatic events, fire, etc.)
Resources are stable and plentiful.
i.e. bacteria, fungi, insects, small rodents.
k-strategists
Populations exist at or near the “k” phase of the growth curve.
Expand tremendous energy raising few offspring.
Give a lot of care to offspring
Population is near “reproductive capacity.”
Population is controlled by density dependent factors (i.e. competition predation, etc.)
There is a high degree of competition for limited resources.
i.e. long lived plants, large mammals, humans, raptors.