Abstract
Animals whose body temperatures are affected by their surroundings are said to be ectothermic. If an ectothermic organism is exposed cold conditions, the heart rate of the animal lowers. In high temperatures the heart rate of the animal is very high. Caffeine being a stimulant works by causing the nervous system to work faster. It further leads to the constriction of the blood vessels. The Daphnia magna sometimes referred to as the water flea lives in the fresh waters. It is an exothermic crustacean. The results of Table one shows that Daphnia’s heart rate lowers as temperatures the temperatures were lowered. Based on these results, a conclusion can be drawn that Daphnia’s heart rate will decrease anytime Daphnia is introduced into a cold environment. At some point of time, Daphnia would die as a result of freezing, but excluding that fact the heart rate would diminish with cold temperatures. The second table depicts the caffeine’s effects on Daphnia. These results exhibit no trend thus do not reinforce the hypothesis. This experiment shows the practical application of temperatures and chemicals in regulating the functionalities of animal’s body. It depicted the most preferred temperatures of an ectothermic creature are standard temperatures.
Introduction
Animals whose body temperatures are affected by their surroundings are referred to as ectothermic animals. This means that the animal’s internal body temperature changes with that of the environment. If the surroundings are warm the animal automatically becomes be warm. The reason for this is that the animal lacks the natural temperature regulating mechanism within the organs. When an ectothermic organism is cold, the heart rate of the animal lowers. In high temperatures the heart rate of the animal is very high. A critical temperature point is attained when the animal’s heart may be injured by a further temperature rise (Campbell 62)
Caffeine being a stimulant works by causing the nervous system to work faster. It further leads to the constriction of the blood vessels. These effects combined together create a synergistic effect and multiply the heart rate. As more caffeine is added to the system the heart rate increases. Too much caffeine may lead to a complete breakdown of the heart (Salant, William and Rieger 64).
The consequence of one outside material can impair with the effects of others. This experiment was done by first invigorating an organism. As a result, the nervous system shall have challenges responding on the introduction of a stimulant.
Background
The Daphnia magna sometimes referred to as the water flea lives in the fresh waters. It is an exothermic crustacean. The body of this organism is transparent; therefore, the effects of substances on its body can be observed and recorded without performing any surgical procedure. The heart and the dorsal backbone can be observed. They are located just close to the head (Helms 134). On normal conditions the Daphnia has an approximate heart rate of 180 per minute. The experiment is tailored to enable the observer to observe the effects of fluctuations in temperature and caffeine in this organism.
Hypothesis
Hypothesis 1:
Lowering the temperature surrounding the Daphnia magna makes the heart rate slower, while raising the temperature increases the heart.
Hypothesis 2:
The heart rate will increase with an increase in the caffeine concentrations.
Materials and methods
We took a reading of the heart rate of Daphnia at room temperature. The reading was recorded by totalling the heart beats for ten seconds and then the heartbeats were multiplied by 6 to give beats per minute. Consequently, ice water at five degrees was used to fill a glass Petri dish ice. The ice cold water Petri dish was positioned on the microscope’s stage, and Daphnia magna placed on top of the dish. After the Daphnia had been allowed a minute to adapt to the changes, a consequent heart rate reading was engaged. The temperature of ice was also recorded.
After allowing the Daphnia to recuperate for some time in a jar, we obtained a plastic pipette and started off by cutting off its tip at the initial graduation from the lower end to permit the Daphnia magna to fit into it. Each one of us acquired a depression slide and smeared some petroleum jelly a single well. The excess jelly was wiped off in order to leave a single layer on the well. Then using the pipette, we drew the Daphnia magna from the jar, recorded its heart rate and placed it on the well covered petroleum jelly. A Kimwipe was used to draw off excess water from the slide. Then one drop of 0.001% of caffeine solution was placed on the Daphnia magna and recording its heart rate after a minute. Then a Kimwipe was used to remove the 0.001 % caffeine solution, and 0.01 % caffeine solution was added and the recordings of the heart rate of the Daphnia were taken after a minute. The same procedure was repeated with recordings taken until a final solution to be added was the 1% caffeine solution.
Results
The results were recorded in the following tables
Discussion
The results of Table one shows that Daphnia’s heart rate lowers as temperatures the temperatures were lowered. Based on these results, a conclusion can be drawn that Daphnia’s heart rate will decrease anytime Daphnia is introduced into a cold environment. At some point of time, Daphnia would die as a result of freezing, but excluding that fact the heart rate would diminish with cold temperatures. With the same thoughts, increasing environmental temperatures would increase the heart rate of Daphnia until high temperatures are attained which makes daphnia survival impossible (Ccirouo et.al 177). These results did not fully support the hypothesis since no provision for the likelihood of death in the hypothesis is present. If the results had reinforced the hypothesis then Daphnia may have had a higher heart rate at 45 degrees instead of dying.
The second table depicts the caffeine’s effects on Daphnia. These results exhibit no trend thus do not reinforce the hypothesis. This could be as a consequence of an experimental error. The wiping of caffeine solution from the Daphnia using Kimwipe could not have been accurate. The Daphnia could also have been mishandled leading to errors. Another possible reason was that may be the daphnia was initially weak. The heart rate recordings of Daphnia in the temperature experiments were considerably lower than that in caffeine solution used in the solution experiments. This could show that the solution Daphnia was strong at the onset of the experiment. As a result the caffeine exposure was recoverable for the Daphnia
Daphnia ectothermic qualities explained the effects of temperature on the animal. (Campbell 90) Daphnia became inactive in lower temperatures as compared to room temperature. This was anticipated although Daphnia lives in cold water (Heugens 1401). When the caffeine was introduced to the system, the heart rate of Daphnia increased to a certain level which leads to death. This was unexpected basing on knowledge on the effects of stimulants on animals (Villegas 133). This can be explained by the extreme nervous system reticence caused by the caffeine.
Conclusion
This experiment shows the practical application of temperatures and chemicals in regulating the functionalities of animal’s body. It depicted the most preferred temperatures of an ectothermic creature are standard temperatures. It also demonstrates that chemicals may be introduced to an animal with the aim of sedating or recovering it. These concepts have a palpable practical application in the field of medicine. They can also be applied in biological research to keep the samples alive, sedated for observation, or revived.
Works cited
Campbell, Neil A., and Jane B. Reece.Biology. 6th ed. San Francisco: Benjamin Cummings, 2002. Print.
Ccirouo, I.-r, D Ceballos, A Lee, and L Vinson. "Making the Most of the Daphnia Heart Rate Lab: Optimizing the Use of Ethanol, Nicotine & Caffeine Knowing What to Expect Makes This Experiment More Effective." American Biology Teacher. 72.3 (2010): 176- 179. Print
Helms, Doris R., Robert J. Kosinski, Carl W. Helms, and John R. Cummings.Biology in the laboratory. 3rd ed. New York: W.H. Freeman, 1998. Print.
Heugens, EH, LT Tokkie, MH Kraak, AJ Hendriks, Straalen N. M. Van, and W Admiraal. "Population Growth of Daphnia Magna Under Multiple Stress Conditions: Joint Effects of Temperature, Food, and Cadmium." Environmental Toxicology and Chemistry / Setac. 25.5 (2006): 1399-407. Print
Salant, William, and J. B. Rieger. The toxicity of caffein: an experimental study on different species of animals.. Washington: Govt. Print. Off., 2012. Print.
Villegas-Navarro, Arturo, Esperanza Rosas-L, and José L. Reyes. "The Heart of Daphnia Magna: Effects of Four Cardioactive Drugs." Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology. 136.2 (2003): 127-134. Print
