Exponential Growth

1
Exponential Growth
X X2
Gen. 1 2 4
Gen. 2 4 16
Gen. 3 16 256
Gen. 4 256 65,536
Gen. 5 65,536 4,294,967,296
2
Exponential Growth
Requires Unlimited Resources No Predation This
type of growth is impossible to sustain If E.
coli grew like this after 48 hours the mass of
the E. coli would be equal to that of the Earth.
3
Logistic Growth

• Carrying Capacity of a population
• Population growth slows down when numbers get
  close to carrying capacity

4
Oscillation at Carrying Capacity

• Populations rise and fall around the carrying
  capacity
• The carrying capacity can rise and fall as well
• What might cause the carrying capacity to change?

5
Density Dependent/Independent Variables

• Density Dependent Variables
• Dependent on population sizes
• Examples
• Competition, predation, disease, etc.

6
Density Dependent/Independent Variables

• Density Independent Variables
• NOT Dependent on population sizes
• Examples
• Temperature, forest fire, flooding, etc.