Lab Report For Daphnia Magna Experiment

After completing the experiment we found that when we gave the Daphnia caffeine the heartbeat rate did show an increase. However, we also found that alcohol also increased the number of times the heart beat. Even though we performed all of the experiments very carefully, we cannot be certain that the effect we saw was due to the drugs. Perhaps the change in heartbeat rate is caused by

Individual Daphnia magna are transferred to a microscopic slide using a pipette. The Daphnia was moving freely in a drop of H2O on the slide. For the control, the heart rate of D. magna is observed for 15 seconds

The dependent variable is pulsation rates of L. variegatus before and after they were in the treatments. The standardized variable of this experiment would be the temperature of the surroundings of the L. variegatus, the three pulsation rates taken for each worm before and after the treatments, and also the amount of time each worm was kept in their respective treatments. The level of treatment for this experiment would be ten because of the six different concentration treatments of caffeine and nicotine along with the four household drugs. The sample size of the experiment differed from some treatments to other. For the three different concentrations of caffeine and nicotine, the sample size was 18 black worms each. The sample size of the control treatment of week 1 was 6 black worms. 12 black worms were used for the control of week 2, decaffeinated coffee and instant coffee. 11 black worms were used for the tea treatment and 15 were used for the tobacco treatment. There were three replications of the pulsation rate readings per worm before and after the treatment. With all this information we were able to get the results we got.

Then using a disposable pipette we placed two drops of room temperature water (21 degrees) on top of the Daphnia. Then placing it careful under the microscope with a for 15 seconds using a tally counter and clicked away how many heart beats we observed and did this three times for three trials, in between the times would give the daphnia a two minute recovery period. We then would process the trials information and calculate an average. After the information calculated we then  multiplied our results by four to see the average heart beats per minute with room temperature water. We gave the daphnia five minute to recover then went on to proceed with two drops of hot water (40 degrees celsius) placed on top of the Daphnia using the pipette. Again three trials for 15 second using the tally clicker following after a two minute break. The same followed for the cold water (0 degree celsius) placing two drops on top of the Daphnia administered by pipette. In between the transitional water temperature trials we then cleaned up the excess water before placing new drops of water by gently soaking up the water with kimwipes. After five minutes we tallied the heartbeats of the Daphnia before administering the epinephrine. Then again gently gave two doses of epinephrine using a new pipette. Then after we observed and tallying the heart beats before administering the epinephrine, three times again recording our results then averaging it. Then we placed two drops of the epinephrine on top of the daphnia, tallying the heartbeats and recording and calculating our trial results. Then after two minutes we observed and tallied the effects after the epinephrine had been used.  Each trial again consisted of observation under the microscope, tallying and observing the behavior internally and externally of the

After the results were recorded, the cavity slide was removed and placed on the working bench. The daphnia was then removed using a pipette and placed in an open container filled with a caffeine concentration of 0.2%. The Daphnia was left in there for 1 minute so it could adapt to the new environment.

The tachycardia is the “faster than normal heart rate at rest” (mayoclinic, 2015). The bradycardia is “the slower than normal heart rate” (mayoclinic, 2015). In the lab procedure, the students had to perform certain criteria to elevate or decline the HR of the Daphnia Magna’s and record their data collections in the Supplemental Lab Manual (SLM) table on pg. 42. Each

The two drugs that have been used in this experiment to test their effects on the heart rate and depolarization rate of the P wave of the crayfish. Depolarization is defined as the contractions of heart muscle, and it is shown in P wave pattern of the ECG. Comparing the results of the trials of epinephrine drug to the resting state, it shows that this drug increases the heart rate, decreases beat period, and decreases the time that take

Throughout my experiment my control acted normally, the daphnia had average movement and calm manner. On a scale from 1 to 5 I ranked the control group as a 3 for normal movement and health. When I introduced car antifreeze to my pure water daphnia there was an immediate change in the color of the daphnia, their bodies turned from a white opaque color to a light pink (the same color as the antifreeze). Not only did the physical appearance change but their behavior became more aggressive and panicked. As time passed the daphnia moved in a circular motion and the chemical caused one of their antennas to cripple. The antifreeze surprisingly resulted in no deaths so I gave the effect of antifreeze to daphnia a 2 (table 2 and 2B). When exposed

Mann-Whitney U statistical testing was performed to see if the result obtained for the difference in heart rate of Daphnia before and after the addition of stimulant was significant. The statistical test for the difference in heart rate of daphnia observed after the addition of aged water is shown on table 2:

Daphnia, or water fleas (named after the jerky, jumping way in which they move), are tiny planktonic crustaceans measuring around 1mm in length. They live in freshwater lakes and ponds, filter feeding on green algae, bacteria, yeast and phytoplankton, before being the prey of small fish such as sticklebacks and minnows. As a primary consumer, Daphnia provide an important link in the human food chain; increasingly larger fish such as salmon are dependant on their numbers. In terms of their nutritional values, adult Daphnia have a protein content of approximately 50% dry mass and a fat content of 20-27%. (Clare) (Background information on Daphnia)

After the Daphnia was given time to calm down, the team took a reading of its heart rate at room temperature (27 degrees C). The reading was taken by counting the heart beats for ten seconds and then multiplying by six to yield beats per minute. Next, a glass Petri dish was filled with ice water at five degrees Celsius. The cold water Petri dish was placed on the stage of the microscope, and the Daphnia was placed on top of the dish. When the Daphnia had been given a minute to acclimate to the changes, another heart rate reading was taken. Then the same procedure using the Petri dish to changed environmental conditions was used with cold tap water (23 degrees), warm tap water (30 degrees), and hot tap water (45 degrees). A heart rate reading was taken for each temperature.

In my experiment as the concentration of sugar increased the heart rate of the Daphnia decreased. The cause of this may have been to the possibility of having a defectuos daphnia. My prediction was that the more sugar concentration added the highest the Daphnia heart rate was going to be. It did affect my organism but not in a positive way if not in a negative way, by decreasing the heart rate of the organism.

Daphnia are normally used to test potentially harmful substances in water supplies, and are easy to handle and monitor. This experiment was designed around this fact,

The experiment was conducted by a number of individuals to see how the effects of a substance would have an effect on a Daphnia. The Daphnia’s were placed in multiple different substances environment to see the effect it would have on their heart rates. When doing the experiment the first step was to take the Daphnia and put it a Water solution to observe the heart rate of the Daphnia and record the heart rate. Recording of the heart rate were taken for when the Daphnia were in the Water solution that way they could compare with the next solution which was Caffeine.

In the presence of excess T3 and T4, an increase in number as well as affinity of beta-adrenergic receptors in the heart is noted. These receptors facilitate the action of "fight, flight and fright" hormones ( epinephrine, norepinephrine) which are positively chronotropic ( beat faster) and inotropic ( pump harder) to the heart. This may then lead to cardiac failure in older patients.