What are Daphnia and why are they used for experiments on heart rate?
The effect of caffeine on heart rate can be investigated using Daphnia (water fleas). The beating heart of a water flea can be seen through its translucent body, by placing the flea in a few drops of water in a cavity slide under the microscope. A mobile phone can be used to video the heart beat.
Why do some Daphnia have different heart rates than others?
Daphnia is poikilothermic, which means that its body temperature and therefore its metabolic rate are affected directly by the temperature of the environment. The change in metabolic rate is reflected in the rate at which the heart beats (cardiac frequency).
Which solutions increased the heart rate of Daphnia?
Dopamine, like caffeine, increases the heart rate of Daphnia in a dose-dependent manner. Dopamine’s effects on Daphnia’s heart has not been reported previously.
What is a Daphnia heart rate?
Results. Seventy-two Daphnia were used in the initial experiments. The average initial heart rate was 354 beats minute——1 (range: 91——521 beats minute——1). The large variation in heart rate between animals cannot be attributed to variation in their size.
Why does ethanol decrease Daphnia heart rate?
Throughout five trials, we tested these organisms and 5% ethanol combined with aquarium water, we found that ethanol alcohol caused the heart rate of the daphnia to decrease, in this case, due to a decrease in action potentials in the organism.
What is the heart rate of a Daphnia?
How does a Daphnia heart work?
Daphnia have an open blood circulation. The heart is located dorsally and anterior from the brood chamber. At 20ºC, it beats about 200 times per minute, slowing down at lower temperatures. Blood cells are easily visible through the transparent body as they flow rapidly through the body cavity.
What is the heartbeat of a Daphnia?
Why Daphnia are used in experiments?
The Daphnia–parasite system is particularly suitable for testing hypotheses because it allows for the creation of rather simple experiments. Among the advantages of this system are: Under laboratory conditions (20°C), Daphnia produce their first eggs after 7-15 days (depending on the food level).
Does nicotine increase Daphnia heart rate?
The 25% nicotine solution caused the heart rate to decrease at a steady pace for one minute and then drastically decrease. Multiple trials found that nicotine causes a decrease in heart rate for Daphnia magna, with higher concentrations of nicotine having a stronger effect.
What drugs affects Daphnia heart rate?
Aspirin, acetaminophen, and diphenhydramine slowed the heart rate of the daphnia by 29%, 12%, and 6% respectively. Furthermore, daphnia exposed to aspirin and acetaminophen were associated with arrhythmias, or irregular heart rhythms. All over-the-counter medications tested affected the daphnia’s heart rate.
How can I measure Daphnia’s heart rate open ended?
Take a sample daphnia and expose it to 1% ethanol and count the heart rate by observing the crustacean under a microscope. Open ended section allows students to explore other factors that can affect the heart rate. Investigation: Daphnia Heart Rate
How does ethanol affect heart rate in Daphnia?
We determined the effects of three concentrations of ethanol, nicotine, and caffeine and of a control solution on heart rate in Daphnia. Ethanol at 5%% and 10%% (v//v) reduced mean heart rate to ∼∼50%% and ∼∼20%% of its initial value, respectively.
Why are Daphnia so easy to care for?
Heart rates recover quickly after removing 5%% ethanol, which allows students to explore reversibility as an alternative to having a separate control group. Daphnia are small crustaceans that are inexpensive, easy to care for, and transparent. The latter property allows students to easily observe the beating heart ( Figure 1 ).
How is the metabolic rate of Daphnia affected?
Daphnia is poikilothermic, which means that its body temperature and therefore its metabolic rate are affected directly by the temperature of the environment. The change in metabolic rate is reflected in the rate at which the heart beats (cardiac frequency).
