AP Biology 7.3 Artificial Selection Question Bank

A sample of a culture of E. coli is plated onto two LB agar plates: plate

1 containing LB agar and no antibiotic (LB) and plate 2 containing LB

agar with 50 micrograms/mL of the antibiotic ampicillin (LB + amp).

Both plates are incubated at 37°C for 24 hours. Bacteria from plate 1

are plated onto two more plates: one with LB agar (plate 3) and the

other containing LB agar with 50 micrograms/mL of the antibiotic

ampicillin (plate 4). Bacteria from plate 2 are plated onto plate 5

(containing LB agar) and plate 6 (containing LB agar with 250

micrograms/mL of the antibiotic ampicillin). This second round of

plates are all incubated at 37°C for 24 hours. A diagram of the

experiment is shown below.

Part A

(i) Describe the process of selection used in this experiment.