Daphnia Practical Writeup

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.

In this experiment there are the following risks both for the human that carries out the experiment and the daphnia:

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

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 Exercise 1, diaminofluorene is used to determine the hemoglobin concentration in the daphnids. A higher hemoglobin concentration is indicated by a darker blue color. A spectrophotometer was used to determine the absorbance at 610nm. When measuring the absorbance levels a blank is necessary to have a zero reference, the blank is the “starting point” for the measurements of the sample (re-word). The blank consists of 10µL of diaminofluorene(DAF), 50µL of hydrogen peroxide, and 0.5mL of PBS. The PBS acts as a buffer in this experiment. The cuvette with the sample of daphnids consisted of 10µL of DAF, 50µL of hydrogen peroxide, and 0.5mL of the sample of Daphnia. In Exercise 2, the Pasteur pipette was used to obtain the sample of Daphnia. The depression slide used in this experiment isolated the daphnid, cotton was used to keep the daphnid still while the heartbeat was counted. The ocular micrometer on the microscope allows the tail spine length to be measured accurately, as well as using an ocular magnification table.

Daphnia, also known as water fleas, are small crustaceans about 1mm-5mm long and are part of the freshwater zooplankton (Ebert 2005, Hutchinson 2005 & Clifford 1991). Daphnia can be found in most fresh water habitats such as freshwater springs, ponds and reservoirs and are the predominant food for planktivorous fish. Dapnia are ‘filter feeders’ meaning they feed on small particles suspended in the water which can include algae. It has been found that daphnia tend to migrate to the upper parts of the water at night and return to the lower parts of the water in the day to hide from predators (Ebert 2005) (Hutchinson 2005). Daphnia can reproduce through sexual reproduction and also asexual

In order to complete this exercise, two different procedures were conducted; one measured the basal heart rate, and the other measured the drug-induced heart rate. A sample 's basal heart rate can be defined as the “resting” heart rate. This is when no drugs or altering substances are applied. In comparison, the drug-induced heart rate of a sample can be defined as the heart rate after the drug was administered to the surrounding environment. The four drugs tested on the Daphnia specimens were Acetylcholine, Caffeine,

Thesis: Caffeine can have many different effects on the body depending on the amount of consumption.

Common testing conducted by researchers uses many features of Daphnia. The transparency of Daphnia and the visibility of their hearts is the basis for the majority of experiments conducted on Daphnia. (Villegas-Navarro, Roses-L & Reyes, 2003). Many other researchers have conducted experiments on Daphnia while also paying attention to the cardiovascular region of Daphnia (Campbell & Matthews, 2004). Researchers have

The data from the mean indicates that caffeine consumption resulted in a heart rate increase for all the patients at an average of 12 units from the normal rate. In addition, the standard deviation post consumption is consistent with mean as it was represented by a factor of 9.74 before the caffeine and 11.58 after. The high deviation after caffeine could be attributed to the fact that caffeine does effect each person differently. The median and mean relate heavily, showing that there was not a large presence of outliers in the data and that there is consistency between each participant’s response to caffeine. The normal distribution of the data was evidenced by the interquartile deviations where the lower quartile was 63.50 before patients were served with coffee and upper quartile of 77.50 and with simultaneous changes after caffeine drinks with low quartile being 74.50 and upper quartile at 92.50. The quartiles distributions show steady changes in heart rate with respect to

In this experiment we find how caffeine can affect the heart rate of a culture Daphnia. Heart rate of a living organism’s can vary depending on the individual, age, body size, heart conditions, medication use and even temperature. This report will examine if the caffeine is good or bad for the living organism’s health and body. And discuss about where the caffeine is produced and used in daily life of human beings and on the environment. Daphnia is a water flea used in this experiment because of its genomic infrastructure with wide range of phenotypic diversity. This quality of Daphnia makes them a versatile model for the experiment. Also their transparent body allows the experimenter to visually see how the heart beats and count them under the light microscope during the experiment as required. The heart rate of Daphnia is monitored under different concentration of caffeine solution and the results are shown in a table and a graph. Experiment carried out to locate the effects of caffeine on a heart rate of Daphnia may or may not be a predictor of change in human heart rate under caffeine. The effects of caffeine can also be tested on humans but those experiment involving humans contains high risk, as Daphnia can only live for a short period of time and in nature most of them get eaten within their first few days or weeks of life.

My hypothesis was, as the concentration of alcohol increases the lower the heartbeat of the Daphnia will fall. To test my prediction I carried out 25 individual experiments which were all carried out using the same procedure but varying the alcohol concentration of the solution. To investigate how alcohol concentration affects the heartbeat of Daphnia I recorded the heartbeat of 25 Daphnia for a period of 7 minutes. This included 1 minute before submersion in alcohol, 3 minutes during submersion in alcohol and 3 minutes after submersion in alcohol. I then found the percentage decrease of the heartbeat of the Daphnia from the resting heart rate.

The experiment took place in a laboratory setting, and the first step was obtaining sixty individual Daphnia magna (that were neither adults nor tiny offspring) from a large tank in the lab. These individuals were equally divided into three groups; low density, medium density, and high density. The twenty Daphnia assigned to the low density group were split into four groups of five and pipetted into one of four tubes filled with 10mL of Chlamydomonas algae. The twenty Daphnia assigned to the medium density group were split into two groups of ten and placed into one of two tubes also filled up to 10mL with Chlamydomonas. The final twenty Daphnia were all placed into a single tube filled with 10mL of the algae. In order to avoid suffocation-related

This experiment is being performed to show the effect of pH levels on daphnia by changing pH levels and measuring the heart rate.

One part of the human body that too much consumption of caffeine can affect negatively the your heart. Caffeine speeds up your brain cells, which speeds up your heart beat in the process. Too much caffeine will also raise your blood pressure. Caffeine using adults were polled on their stress levels given a 1 to 5 rating, with 5 being the most stressful. With each stress rating, each adult averaged a 1.7/0.4 mm Hg in blood pressure, and 1.8 beats per minute more in heart rate than adults in the lower stress rating (Lane, J.D., 2002). With further testing, they found that stress level and caffeine went hand in hand, with the highest caffeine users being the ones with 5 stress ratings. This study showed that consuming caffeinated beverages raises your blood pressure and heart rate by a considerable amount. In the same study as above, they used 500 mg of caffeine (close to 4 cups of coffee) to see how much it raised a person’s blood pressure throughout a single day. On average a person’s blood pressure was 4 mm Hg higher during than day than on a normal