practical 10

• Required Practical 10


  Investigation into the effect of an environmental variable on the movement of an animal using either a choice chamber or a maze
• Woodlice


  • Respond differently to different environments
  • Increase the frequency at which they change direction
  • Move faster
  • This increases their chances of finding a more favourable environment, which increases their chances of survival
• Kinesis


  The response of woodlice to seek a more favourable environment
• Choice chamber


  Can be set up to show different environments and will demonstrate kinesis in woodlice as they seek to move to a more favourable environment
• Equipment


  • Choice chamber
  • Woodlice
  • Water
  • Drying agent
  • Dark Paper/cardboard
  • Paper towels
  • Spoon
• Method


  1. Set up choice chamber to have four quadrants: dark and dry, dark and damp, light and dry, light and damp

  2. Use dark paper or cardboard to block out the light on one half

  3. Use wet paper towels to make damp areas

  4. Use a drying agent such as anhydrous calcium chloride to make dry areas

  5. Place 10 woodlice in the centre of the choice chamber using a spoon

  6. Leave for 10 minutes

  7. Record how many woodlice are in each quadrant

  8. Repeat by moving woodlice back to the centre of the choice chamber and repeating steps 3-4
• Risk Assessment


  • Biohazard: Contamination from live specimen
  • Safety Precaution: Wash hands after handling
  • In emergency: Seek assistance
  • Risk Level: Low
• Chi Squared


  Can be used to determine whether the observed results differ from the expected results
• If the Chi Squared value exceeds the critical value at the 0.05 level of significance, you can reject the null hypothesis, as there is a less than 5% probability that your results are due to chance, so there is a statistically significant difference between the observed and expected values
• Where o is the observed frequency and e is the expected frequency