Animal Behavior with Isopods Responses to Environmental Variables Objectives • Observe animal behaviors relating to environmental stimuli • Design and conduct an animal behavior experiment • Use Chi-Square to determine statistical significance of the data collected Animals: Isopods • Porcellio laevis (sow bugs) or Armadillidium vulgare (pill bugs) • Land-dwelling (terrestrial) crustaceans • Related to lobsters, crabs and shrimp What do you know about isopods? Isopod Taxonomy • Kingdom Animalia • Clade Euarthropoda (arthropods) • Subphylum Crustacea (crustaceans) • Class Malacostraca • Superorder Peracarida (presence of a brood pouch) • Order Isopoda Isopods • Prefer dark, humid environments • Breathe with gills which must remain moist • Females may carry up to 200 eggs in a brood pouch (located under thorax) • Molt as they grow Isopod Behavior
• Porcellio laevis (sow bugs) – flee or remain perfectly still when threatened • Armadillidium vulgare (pill bugs) – curl up in tight balls for protection Three Part Lab
• Activity A1: Initial Observation of Isopod Behavior • Activity A2: Orientation Behavior of Isopods • Activity A3: Designing an Experiment to Test Isopod Behavior Animal Behaviors
• Observe two innate behaviors in isopods • Orientation behaviors: taxis and kinesis Behavior: Taxis • Taxis: Turning of an animal’s body towards or away from a stimulus (directional) • Positive taxis (towards) and negative taxis (away) • Specific examples include phototaxis and chemotaxis Behavior: Kinesis
• Kinesis: Random turning or movement of an animal in relation to a stimulus, usually to find “comfort zone” • May involve a change in rate of movement Behaviors Evolve by Natural Selection
• Some unicellular protists move towards light (positive phototaxis) • Earthworms move away from light (negative phototaxis) • Some bacteria move towards high concentrations of glucose (positive chemotaxis) Activity A1: Initial Observation of Isopod Behavior • Observe the isopods for 10 minutes in a petri dish • Undisturbed behavior • Make notes on the isopods’ movements – Agonistic (related to fighting: threats, displays, retreats, placation) – Taxis and/or kinesis Activity A2: Orientation Behavior of Isopods
• Observe isopods as they respond to humidity differences in their environment over time Scientific Question: Do differences in humidity affect isopod behavior?
• Alternative Hypothesis (HA):
• Null Hypothesis (H0):
• Independent Variable:
• Dependent Variable: Activity A2: Orientation Behavior of Isopods • Clean filter paper on each side of choice chamber • Use pipet to saturate the filter paper on one side of the chamber with water (no excess) • Transfer 5 isopods to each side of chamber • Count and record the number of isopods on each side of the chamber every 30 seconds for 10 minutes • Continue to record even if the isopods stop moving Activity A3: Designing an Experiment to Test Isopod Behavior • Select one variable listed below to investigate
Variable Conditions Temperature Cool, Warm Light Light, Dark/Shade pH Low pH (Acidic), High pH (Alkaline) Substrate Surface Smooth vs. (Choose one) Choice Chamber and 10 Isopods Before You Begin….
Complete Parts 1-5 and then check in with me: • State the factor to be tested • State a hypothesis for your experiment • List the materials needed for the experiment • List the procedure to be followed • Describe the data that will be collected and how the results will be displayed (qualitative and quantitative) Materials
• plastic bags • wax paper • warm water • plastic wrap • ice • colored paper • light source • cotton • aluminum foil • screens • gravel • filter paper • KOH (alkaline) • tissue paper • HCl (acidic)