An Investigation to Show the Effect of Temperature on Daphnia :: Papers

An Investigation to Show the Effect of Temperature on Daphnia Plan: I will submerge some daphnia contained in a test tube in water of differing temperatures and measure their subsequent heart rates. Hypothesis I think that the heart rate of the daphnia will increase up until around 40ËÅ ¡C at which point most of the daphnia's enzymes will have denatured and rate of metabolism will have stopped or decreased sufficiently to have stopped the daphnia's heart rate. Apparatus list Test tube Beaker Different temperatures of water Daphnia Pipette Stop clock Microscope Slide Safety Follow usual lab safety rules. There are no major safety considerations in this experiment as the daphnia aren't harmful and water above 40ËÅ ¡C will not be used. Method To determine if temperature does have an effect on the daphnia, I intend to carry out the following experiment. The experiment will involve measuring the cardiac activity of the daphnia at different temperatures, ranging from very cold (approx. 5 degrees Celsius) to quite warm (approx. 40 degrees Celsius). ÂÂ · A selection of similar sized/age Daphnia will be taken. ÂÂ · A variety of different temperatures of water will be set up, these temperatures will be kept constant whilst the daphnia are submersed in them. The temperatures will be set up by using ice to cool tap water down to lower temperatures and boiling water to heat it up. The temperature will be measured to within 0.1ÂÂ °C on a mercury thermometer to ensure accuracy. The temperatures will range from 10ÂÂ °C to approximately 40ÂÂ °C and it will be done at 5ÂÂ °C intervals. ÂÂ · The daphnia will be submersed in the water and left to equilibrate for 3 minutes, after this time one of the Daphnia will be removed and put onto a microscope slide, this will then be quickly put under the microscope. -1- ÂÂ · Under the microscope, the Daphnia will be observed for 20 seconds, this heart rate will be counted and recorded, this can the be