• May 2, 2018

This week, students in Advanced Placement biology have been practicing ethology, or the study of animal behavior. Behavior is an animal’s response to sensory input and falls into two basic categories: learned and innate (inherited).

  • Orientation behaviors place the animal in its most favorable environment. In taxis, the animal moves toward or away from a stimulus. Taxis is often exhibited when the stimulus is light, heat, moisture, sound, or chemicals. Kinesis is a movement that is random and does not result in orientation with respect to a stimulus. If an organism responds to bright light by moving away, that is a taxis. If an animal responds to bright light by random movements in all directions, that is kinesis.
  • Agonistic behavior is exhibited when animals respond to each other by aggressive or submissive responses. Often the agonistic behavior is simply a display that makes the organism look big or threatening. It is sometimes studied in the laboratory with Bettas (Siamese Fighting Fish).
  • Mating behaviors may involve a complex series of activities that facilitate finding, courting, and mating with a member of the same species.

Students have observed changes in behavior in pill bugs, or “roly-polies”, as they hypothesize whether the animals have adapted to perceive and react to certain environments. They have also designed their own experiments to determine how isopods respond to environmental changes.

The procedure included placing 10 isopods and a small amount of bedding material in a Petri dish, observing the isopods for 10 minutes. Students made observations and notes about their general appearance, movements about the dish, and interactions with each other.

After the observation, students were tasked with placing a moist piece of filter paper on one side of a choice chamber and a dry one on the other. Students then transferred 10 animals to the moist chamber while 10 were left in the dry chamber. Then, students counted how many isopods were on each side of the choice chamber every 30 seconds for 10 minutes, recording their findings in a table. After the experiment, students created an appropriately labeled graph to illustrate the sample means of the two environments to within 95% confidence. Students then calculated the X 2 value for their data and used this information to accept or reject their null hypotheses.