Daphnia Magna Experiment Essay

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The Daphnia magna species in this experiment were kept and preserved in jars of suitable water that acted as small ponds. Each Daphnia Magna was transported individually using a wide-mouthed pipette to a depression slide. The stability of the Daphnia Magna on the slide was attained by using a drop of pond water that acted as a boundary of movement for the Daphnia on the depression slide, small pieces of cotton wool were also used to act as an extra boundary to stop the Daphnia Magna from swimming in circles in the pond drop it was placed in; the stability factor was important in counting the heart beat rate more accurately. The depression slide was then placed under the stereomicroscope, over a cooling chamber that was used to slow down the …show more content…

The controlled group was left with 0 nicotine applied. The 4 treatment groups were treated with 4 different levels of nicotine concentrations: 25 µm, 50 µm, 75 µm, and a 100 µm. The treatment concentrations were applied on top of the pond drop that the Daphnia Magna’s were trapped in on the depression slide; a minute was given for Daphnia Magna acclimation with the treatments. Then, the heart rate of each of the 3 Daphnia Magna’s in the 5 groups was measured, 3 Daphnia Magna’s were tested in each group to attain the mean so that more accurate results were reached. The technique used was that we counted the number of heartbeats in a 10 second interval and then multiplied that number by 6 to attain Beats/min; an initial (before treatment) HBR and after treatment HBR were recorded for each Daphnia Magna. The raw data were written down in a table and were later moved for demonstration on a graph for the final preview. The data collected matched the expectations, for the controlled group: the heart beat rate was dropping slightly (becoming slower), the reason behind that was most likely the cooling chamber because there was no treatment applied or any other external

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