Cracking the AP Biology Exam




In this lab, students observed the behavior of pillbugs and fruit flies. In 11A, students examined how pillbugs respond to their environment. Pillbugs are crustaceans that respire through gills. The pillbugs were placed in two petri dishes connected by a passageway. One petri dish was lined with dry filter paper and the other one was lined with wet filter paper. The movements of two or more pillbugs toward or away from a stimulus (taxis) were tracked to determine if they preferred one area over the other. This experiment may have been conducted using other environmental variables such as light, acidity, sound or temperature.

In lab 11B, the mating behavior of the Drosophila melanogaster was observed. Mating behaviors involve a complex series of activities that involve finding, courting, and mating with a member of the same species. Generally, students observed the various behaviors in one male-female pair and recorded the results.

What do you need to remember about this lab?

  • Pay attention to the behaviors and environmental variables observed in case you are asked to replicate this study for one of the essay questions on the test. Unlike the other labs, this one did not have a control group.
  • For your experiment, you may want to include a control group to compare the results to your experimental group.