Effect of Nicotine on the Heart Rate of Daphnia





Effect of Nicotine on the Heart Rate of Daphnia


When any new chemicals is introduced to a living organism, there must be a reaction or a certain change. Although that is what is expected, other organisms tend not to reactive to certain chemicals. Daphnia is a very tiny that is under the planktonic crustaceans class also known as water fleas. Their length is between 0.2 to 0.5 mm. Their skeletons have a resemblance with a shell; hard and transparent. Having an ability to adapt any aquatic environment, they are common aquatic organisms. Although people choose to conduct an experiment on effects of nicotine on daphnia, fatal results are expected (Smirnov, 94). Different organisms like frogs and fish and many others feed on daphnia. Adding to that, most lab experiments including drug tests and many others use daphnia thus makes it a common organism in the laboratory. Daphnia heart rate test is the most common test done using this organism.

Daphnia bodies changes with environmental changes as they are ectotherms thus very ideal for testing the heart rate. An investigation whether nicotine affects the heart rate of daphnia is what this paper is explaining. However, many experiments have not shown the effects, it is going to use a ticker timer to count the heartbeats, where a marker/pen will be used for too fast rates. The heart rate before (control) and after nicotine introduction (test) will be recorded and differences obtained. Afterwards, laboratory analysis will be done and the results will be displayed in tables and calculations be done accordingly. After introduction to nicotine, the Daphnia heart rate was not affected much, it only increased a little bit but at its normal heartbeat rate expected. Thus this implies that nicotine does not have/ has a very little effect on the heart rate of Daphnia (Corotto, Ceballos and Vinson, 173).


            Tobacco solution is obtained from cigarette. Approximately 20 cigarettes are enough to make a tobacco solution. After the extract is mixed with water, it was covered for 12 hours then sieved into another container. The reason for doing this is to extract nicotine from tobacco. Regarding to that, a different solution is obtained in comparison to water. Referring to the Washington Association for Biomedical Research, the study is done beginning with solutions with lower to higher concentration to find out the exact concentration that Daphnia can survive with. On this you have to make a note that cigarettes have different concentrations of nicotine; lowest have 0.3mg/cigarette while 1.7mg/cigarettes the highest. Having this knowledge, the choice of the cigarettes to use on the experiment is obtained. The information on the concentration of the tobacco solution is essential as living organisms heartbeat rates are highly affected by nicotine concentration; may cause death as they are fatal (Smirnov, 94). The water used (from daphnia aquatic habitat) is the same used to extract nicotine (test) and also used as the control (water in experiment).


            The main purpose of this experiment is to establish the effect of nicotine on the heartbeat rate of a transparent crustacean called Daphnia magna. Different results of nicotine effect on Daphnia are expected. However, as nicotine is a stimulant, it eventually increases the rates of metabolism, thus there are very high possibilities that the heartbeat rate may increase a little with an increase in nicotine concentration. To add on that, with high heartbeat rates, Daphnia my die as this condition is fatal. For better results, the same age, culture of Daphnia among others has to be used. In addition to that, the daphnia solution and the animals need to be collected from the same aquatic habitat to be sure of the results (Derby, Charles, and Martin, 545).

Question: How will nicotine affect Daphnia’s heartbeat rate?

Ethical Issues

            While handling these animals, students should be extra careful as they have to be handled in such a way which illustrates ethical attitudes that are good regarding experimental animals. In addition, even if it is a fact that they are organisms that have minimum capabilities thus might not go through suffering as those higher animals, they are not exceptions thus deserves respect equally. After this experiment, all animals must be returned to their aquatic habitats, by doing that, it will be in support of different biological organizations experimental guidelines. Therefore students must first do a theoretical analysis of Daphnia Magna, its care and how to handle it before embarking on this experiment. In addition, they need to be complaisant with the guidelines of different biological organizations in order to know what is right or wrong   (Whitlock, Michael, and Dolph). However, in this experiment, a study and a wide research were done and also Scientific Operation Procedure S&OP was designed and submitted for approval by the supervisor. Note that while in the laboratory observe your and the animals safety (Whitlock, Michael, and Dolph).


  1. Cotton wool
  2. 3 droppers
  3. Tobacco solution
  4. Chart of Daphnia anatomy- for getting sources
  5. Microscope set to low power resolution
  6. 2 depression slides
  7. Kleenex
  8. Daphnia Magna- water flea culture
  9. 2 (22 by 60) cover slips
  10. Water from Daphnia Magna aquatic habitat


            First of all you need to record the containers you are using e.g. rinse water, nicotine water and Daphnia water. Adding to this, make sure all droppers are marked and placed in places you cannot mix. Secondly, place the Daphnia on the slide using its dropper. Under a low light microscope, do a keen observation of the organism. By doing this, you will be able to locate the heart and entire body of Daphnia. After that, turn off the light to enhance tracing the position of the Daphnia if you are observing it directly. Thirdly, after the organism is used to the slide life, use a cover slip to cover the slide to hold it in a fixed position. After Daphnia has settled, suck some nicotine and gently remove the cover slip then using cotton wool sponge the liquid around Daphnia without touching it. Nicotine has to be put in the depression slide as Daphnia cannot survive in the absence of a liquid. By the use of a ticker timer to record the heartbeat rate after 2 to 3 minutes after nicotine was introduced and if Daphnias heart is still beating, reintroduce it to original aquatic water on a Petri dish a. Repeat the same procedure with pure water as a control. Note that 5 Daphnia have to be tested and recorded on a table. Also, a minimum of three replicates has to be produced. Another point to note is without covering the Daphnia with a slip, you can still make observations. Reasons to this are because a free space will be created for Daphnia to make small movements thus a great opportunity to view varying observations. Also from doing that you can obtain important data like the time it takes before stopping to make movements which is crucial and must be recorded in every experiment.


            What was observed is that a Daphnia had an average heart rate of 153.6 immediately test (nicotine) was introduced and after the experiment was over i.e. 2-3 minutes, they recorded an average change of 214.4. The difference obtained from these averages is -15.2 which does not significantly change the heart beat rate. In comparison with the control (water), we find that the difference is almost the same. When water was introduced on Daphnia, the heart beat rate average was 166.6 and after the experiment was over they recorded a change of 157.6 with a difference of 2.5. From both test and control results figures, you can observe that the heartbeat rate was not highly affect or other within normal functioning. Note that from the experiment, the attribution of the heart was not by the specimen size (Corotto, Ceballos and Vinson, 173).

Although water is a control substance, it also had little effect on Daphnia heartbeat rate by decreasing it a little bit, this is seen from the results displayed. Adding to this, even though in the case of nicotine the heart beat increased, both the liquids did not go outside the required range thus making no difference to the heartbeat rate. The results on the Daphnia heartbeat rates are cleared shown on the tables that are included and calculations are also clearly done. The figures shown are experimental actual figures; this means they are exactly as originally recorded from the beginning to the end of the experiment without any data cooked or alterations. The heartbeat rates were taken using a ticker timer with a pen/marker as the rates were too fast for the timer alone.


            From the experiment, an observation can be done that a minimal variation is there in the heartbeat rate between different Daphnias. The lower heartbeat rate is for bigger and higher for smaller Daphnias. Owing to this, the only way to get good results is by taking averages. Also from the experiment, an observation was done that in nicotine the heartbeat rate increases as the organism reacts to it. Observing the heartbeat rate in water, it reduces as Daphnia is settled. Another observation is that Daphnia makes a lot of movements when water is introduced but reduces when nicotine is introduced. From the observations, Daphnia is more active in water than in nicotine. The initial metabolic reaction can be reversed if you return Daphnia to its aquatic habitat, this is as per the experimental observations. In regards to that, it is so evident that the heartbeat rate of Daphnia did not change that much after nicotine was introduced but increased just a little bit.


            For Daphnia heartbeat rate examinations, nicotine is the suitable reagent to be used. The recommended concentrations for this is 5% to 10%, this are not fatal to the organism. A metabolic reaction will be increased by this concentration but cannot kill Daphnia although any increase in concentration will kill the organism. When designing a laboratory experiment on Daphnia heartbeat rate this information is crucial and has to be known. The reason to this is you cannot have a successful experiment when all your organisms are dead. However, it is of great importance for anyone willing to run this experiment to start from testing all nicotine concentration for clarity. An evident conclusion is that at accommodative concentrations used in this experiment, nicotine does not change but only increases Daphnia heartbeat rate a little bit.











Work Cited

Corotto, F., Ceballos, D. and Vinson, L. Making the Most of the Daphnia Heart Rate Lab: Optimizing the Use of Ethanol, Nicotine & Caffeine, The American Biology Teacher 72. 3(2010); 173-179.

Derby, Charles, and Martin Thiel. Nervous Systems and Control of Behavior. , 2014. Print. 545

Smirnov, Nikolai N. Physiology of the Cladocera. London: Academic Press, 2014. Internet resource.

Whitlock, Michael, and Dolph Schluter. The Analysis of Biological Data. , 2015. Print.



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