CPAC1 - Caffeine and daphnia

• Describe method to find effect of caffeine on heart rate of daphnia

  IV = conc of caffiene solution (1% - 5%)

  DV = Heart rate

  CV = vol of coffee, distilled water, temp (room temp), length of time to count heart beat (30 secs), same species

  Method:

  • Place cotton wool on microscope slide (to restrict movement)
  • Add one daphnia
  • Absorb water around it with absorbent paper
  • Place one drop of caffeine sol
  • Leave for 2 mins
  • Measure heart beats for 30 secs - jot on paper
  • Calculate heart rate in 1 min
  • Repeat 2 more times with different concs
  • T test