'Investigate the Effect of Caffeine on the Heart Rate of Daphnia\r'

'Aim: In this prove we atomic number 18 trying to find out how varying the stringency of caffein can affect the ticker lay out of water flea wood pewee.Prediction: I predict that caffeine allow increase the punk drift of the half-pint.IntroductionI believe the results lead comply with my prediction. Caffeine is a compound raise in especially tea and chocolate plants and acts as a natural pesticide.Caffeine is a central aflutter system stimulant importee it increases the amount of neurotransmitters released weting java is a stimulant that affects the central skittish system by increasing its activity. In this feasible the caffeine should put one across a noniceable issuance on the core put of Daphnia as Daphnia absorbs chemicals present in the termination nigh it without selection. I also predict that at that place would be an increase in snapper compute at one time position in decaffeinated hot chocolate as decaffeinated coffee still has caffeine con tent but importantly lower per atomic number 12 than caffeinated coffee.However I testament sojourn the increase of sum of money stray of the culture fixed in caffeinated coffee to be significantly high(prenominal) than the culture placed in decaffeinated coffee. Daphnia: The fence Daphnia is used as the organism in this experimentation is due to its transpargonnt body which makes the heart visible. Daphnia is better than Brine shrimp because soak shrimp is non transp bent meaning heart rate has to be measured by find leg movement. Variables: The independent variant that we change. In this showcase it is the caffeine content.We would be experimenting with water, decaffeinated coffee and caffeinated coffee to expose and comp be its erect on the heart rate of Daphnia. The book for this experiment is a solution with no caffeine which allows us to see if the change in heart rate is due to the caffeine or other factors. To ensure that this experiment is a some(a)what te st only the concentration of the caffeine micturate be changed. Caffeine is the independent variable. I tried and true each particular concentration of caffeine 10 times.I decided this prior to the experiment because there was curb to results that are out of pattern so iterate this many times would eliminate systematic errors resulting in more accurate and reliable information. The dependant variable is the heart rate of the shrimp forget be measured over 10 seconds Ccontrol variables: These are variables that should be kept the very(prenominal). As a result the number other factors other than coffee content are limited. This is needed as the objective is to investigate the effects of caffeine content. The control variables ensure valid data.Volume of solution The time heartbeat is measured within Temperature: Daphnia may be very sensitive to the genus Oestrus therefore the kinetic energy given to them by heat could have effects on the heart rate. Same culture of Daphnia: To minimise hereditary differences. The size of the shrimp can change the layer of the effect of caffeine. The larger shrimp will have a lower heart rate. I will ensure this as best as possible by keeping the Daphnia in the same light intensity by shining a lamp directly at it.Preliminary experimentI did a preliminary experiment to familiarise myself with the methods so no time is superfluous during the actual experiment. It helped me identify the limitations in the experiment and how to fill the experiment appropriately. For example I noted not to add too much of each solution on the microscope as there will be a loss of surface tension and it will spill. I also learnt to not use the skid covers as they kill the Daphnia Analysis The mean heart rate of Daphnia shrimp placed in solution B is 26. 5% higher than the heart rate of the Daphnia placed in the control solution.Furthermore it is 1.9 % less(prenominal) than dissolvent A ( less difference than I predicted. From these re sults we can infer that Solution B is the solution containing decaffeinated coffee. This is because the mean heart rate is lower than caffeinated coffee and higher than the control solution. This is because decaffeinated coffee contains caffeine but significantly lower per milligram than caffeinated solution. However this Solution A, caffeinate coffee caused the daphnia heart rate to increase the most. This proves the hypothesis because the greater the caffeine content, the more neurotransmitters are released.The increase in this neural stimulation is interpreted as an emergency in organisms causing adrenaline to be released therefore heart rate increases. There still appears to be fluctuations that are probably caused by systematic errors. The data from shrimp placed in solution A (caffeinated coffee) has the superlative variation in results at 168 compared to solution B, 108. evaluation Reliability: My results appear fairly reliable because there is an obvious pattern occurs and it defys my prediction. The experiment was carried out as a blind trial whereby the solutions except for the control are unknown.This helps eliminate bias whereby I tangle with’t choose some results and ignore others to support my prediction making the results more reliable. Validity systematic errors could have caused this for example I did not give time for the Daphnia to absorb the solution in advance counting the heart rate. These factors could have also caused the fluctuations in the results so accuracy is questionable. The variation in caffeinated and decaffeinated coffee could have been caused by systematic errors. For example, the Daphnia could have already been dead.There was a significant drop in the midst of the eighth and ninth test of solution A ( around 54. 7%) I did not stockpile this because caffeine is a stimulant drug. This suggest that the shrimp have dissimilar tolerance towards caffeine and some may have been dying. Furthermore the heart rate of s ome shrimp could be distinctly different from the other shrimps as they were trying to escape the cotton wool fibres which requires more energy thus hear rate increases. This suggests that the culture of Daphnia used in the experiment could have contained shrimp that are different geezerhood and size.Although I tested each concentration 10 times, there is still a lot of division of the results. Water, on the other hand has the lowest variableness of only 60. The variability in the other table of contents are at 168 (caffeinated coffee) and 108 ( decaffeinated coffee) This could perhaps be the effect of other chemicals in caffeine which Daphnia are responsive to. Accuracy Certain methods of collecting data were not accurate therefore affecting the validity. For example, a random error such as not tapping the pen in the rhythm of the heartbeat alter the number of heart beats per minute.\r\n'