Four randomly selected Daphnia magna, for each trial, were removed from the provided colony for the bioactive compounds to be tested, and were transferred with a plastic wide-mouth pipette with approximately 10 mL of pond water to protect and ensure survival of the Daphnia. In order to acclimatize the Daphnia to laboratory conditions, they were then placed onto a petri dish on the Daphnia cooling chamber. The cooling chamber was located on the stereomicroscope platform and brought down the heart rate of the Daphnia to a range that was countable by the observer, since Daphnia heart rate at room temperature is too rapid. On the cooling chamber there were two petri dishes: one for the Daphnia that were going to be tested, and one with the Daphnia being tested on, to ensure constant consistent temperatures for each trial. To maintain a temperature conducive to the heart …show more content…
Research Protocol – Monitoring of the Daphnia magna heart rate The experiments focused on the four treatments of nicotine, caffeine, ethanol, and double distilled water (placebo). 180 μL of each bioactive solution (nicotine was covered with foil, due to light sensitivity) and 120 μL of double distilled water were placed into labeled eppendorf tubes to dismiss cross-contamination, and were placed on ice to match the environment of the Daphnia to reduce any added stress on the Daphnia. One Daphnia was placed on the testing petri dish, and then all the excess pond water was removed with a transfer pipette. Immediately 10 μL of double distilled water was added with a micropipette; this way our concentration of the treatment was the intended concentration.
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= 10^-3 M = 1,000 mL Here C1,C2; are the first and second concentrations of solution V1 and V2 ; are the required and current volumes. The impeller turned on and DDA, and tap water left to be mixed properly with water for 2 minutes. Approximately 150 grams of quartz added into the solution.
Corotto, F., Ceballos, D., Lee, A., & Vinson, L. (2010). Making the Most of the Daphnia Heart Rate Lab: Optimizing the Use of Ethanol, Nicotine & Caffeine. The American Biology Teacher , 176-179. The purpose of this article was to test the effects of chemicals on Daphnia magna.
This week we went to the Conodoguinet Creek. While we were at the creek we did many different things. One of the experiments we did was the Critter Count which was my favorite. Another experiment we did was the Eutrophication Tests. The last Experiment we did was the bobber test.
Before getting the goldfish subjects, two beakers were filled with 200 ml fish water and weighed. Four goldfish were then collected gently from the fish tank and each two of them were transferred into one beaker. Each beaker along with fish and water was weighed again to determine the weight of each pair of goldfish. For the control group of each trial, the oxygen chamber was firstly filled with 200 ml fish water; after two goldfish along with 200 ml water were transferred into it, it was sealed in order to prevent oxygen exchange with the ambient environment.
From the above data, one can see that the greater the concentration of caffeine in the water applied to the Daphnia, the higher the average heart rate in beats per minute of the water flea. For example, at 0% concentration of caffeine the average heart rate of the Daphnia was 165 bets per minute however you can clearly see a difference in heart rate with the Daphnia when placed in a 0.5% caffeinated solution as the average heart rate was 268 beats per minute. An increase of 103 beats per minute on
Metabolism The daphnia’s main composition consists of a midgut, hindgut and an esophagus running from its head down its body, using one compound eye as an aid in swimming. The position of the heart is right above where the location of eggs in the females back. The water flea’s usual food source is
As mentioned in the hypothesis, the prediction is that as the temperature increases towards the optimal, the rate of respiration will increase. As the temperature exceeds the optimal, the rate of respiration will decrease. The temperature of the environment can be varied by placing the respiration chamber under a temperature-controlled water bath/cooling bath. The temperatures that will be used in this experiment will range from 0ºC to 50ºC in 10ºC increments. Digital thermometer will be used to measure the temperature of air.
My hypothesis was supported by the experiment. The goldfish’s respiration rate slowed down as the temperature of the water was lowered. The independent variable of this experiment was the temperature of the water, and the dependent variable was the respiration of the goldfish. When the goldfish lowered its respiration rate it did not intake as much oxygen. Without as much oxygen, the goldfish used less energy.
Stimulants increased the worms’ pulsation rate during the experiment. b) After the comparison of data, I found that the mean pulsation rate for the worms suspended in alcohol was slightly lower than the pulsation rate of the same worm before contact with the drug. After contact with the alcohol the mean change of pulsation rate ranged from -2 to 2, with the average result being 0. These shows use that that alcohol did decrease some of the worms’ pulsation
The materials and methods used in this experiment are as written from the Laboratory Supplement of David L. Shultz. To properly prepare for the experiment, the materials needed were one stoppered shell vial or small Erlenmeyer flask for flies, seventy flesh flies (Sarcophaga bullata, ice-cold to anesthetize them), one wire test-tube rack (small mesh), a few paper towels to cut the flies on, one razor blade, one enamel pan, one thermometer, one grease pencil, one piece of plastic wrap, one large plastic beaker filled with crushed ice, seven large glass test tubes to hold reagents, homogenate, and centrifuged fractions, seven glass reaction tubes (small size, about three inches tall), and seven plastic pipettes (one milliliter and controls). When all
The experimental jar was comprised of the Daphnia, five milliliters of fertilizer, 1.764 grams of duckweed, and filtered lake water. We measured the duckweed by setting the weight of the scale to include the container, and then removing as much of the excess water from the plant as possible and depositing it on the scale. The control jar included the Daphnia, 1.727 grams of duckweed, and filtered lake water. An additional jar was added to remove any confounding variables, such as the possibility of the fertilizer alone being the direct cause of the possible diminishment of the Daphnia population. This jar was comprised of Daphnia, filtered lake water, and five milliliters of fertilizer.
Hypotheses: Do you expect heat to be a chronotropic factor? Yes Do you expect heat to be an inotropic factor? Yes Procedure and Results: Control Heart Rate (After rinsing) beats/min Experimental procedure Heart Rate after treatment beats/min Change in Heart Rate beats/min Strength of Contraction after treatment compared to normal (stronger or weaker) Baseline rate: 72 Continuously drop warm Frog Ringer’s onto the heart 48 -24 Weaker Rate after rinsing: 72 Continuously drop cold Frog Ringer’s onto the heart 60 -12 Weaker
The chemical equation for this experiment is hydrochloric acid + sodium thiosulphate + deionised water (ranging from 25ml to 0ml in 5ml intervals) sodium chloride + deionised water (ranging from 25ml to 0ml in 5ml intervals) + sulphur dioxide + sulphur. As a scientific equation, this would be written out as, NA2S2O3 + 2HCL + H2O (ranging from 25ml to 0ml in