Population Change This is Bob
Bob is a bacterium
He is going to show you how quickly
bacteria can multiply.
120
minutes
Plot the information below as a graph:
0
minutes
64 Bobs
140
minutes
20
minutes
40
minutes
60
minutes
128 Bobs
160
minutes
80
minutes
100
minutes
512 Bobs
32 Bobs
So, why doesn’t Bob take over the world?
• LAG PHASE: Growth is slow at first, while the bacteria acclimate to the food and nutrients in their new habitat.
• LOG PHASE: Once the metabolic machinery is running, they start multiplying exponentially, doubling in
number with every division.
• STATIONARY PHASE: As more and more bacteria are competing for dwindling food and nutrients, booming
growth stops and the number of bacteria stabilizes.
• DEATH PHASE: Toxic waste products build up, food is depleted and the bugs begin to die
Extend your graph to represent the stationary phases and the death phase.