What is the effect of caffeine on Daphnia?

What is the effect of caffeine on Daphnia?

Caffeine increases the heart rate of Daphnia in a dose-dependent manner. This experiment was done two times, and a paired t test analysis vs control revealed the following P values: 0.0406 (0.08 mg/ml), 0.0263 (0.16 mg/ml), 0.0367 (0.24 mg/ml), and 0.0189 (0.32 mg/ml). These values are statistically significant.

What is the effect of caffeine on heart rate experiment?

Contrary to the hypothesis, caffeine did not increase the heart rate; however, analysis of the data showed a slight decrease in heart rate over increasing caffeine concentration.

What is the independent variable in Daphnia experiment?

Variables The independent variable was the amount of caffeine we administrated to the daphnia. The dependent variable was the heartbeat of the daphnia before and after their caffeine intake.

Why does Daphnia heart rate increase?

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).

Why does Daphnia heart rate increase with temperature?

One reason why the heart rate of Daphnia increases with temperature would be because less oxygen is present in the warmer water. Consequently, lack of oxygen could result in insufficient amount of oxygenated blood and hence the heart would have to work harder to pump blood around the body.

What is the average heart rate of Daphnia?

354 beats minute—1
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.

What was the control in the Daphnia experiment?

In the case of our Daphnia, an example of a controlled variable would be the temperature of the water in which the Daphnia are tested. This variable needs to be controlled because Daphnia hearts beat faster in warm water than they do in cold water.

What factors affect the heart rate of Daphnia?

How does caffeine increase heart rate?

Once you take that first sip of coffee, the caffeine enters your blood from the stomach and small intestine and begins to stimulate your central nervous system. The receptors in the cells within your heart are stimulated by the caffeine and increases your heart rate.

Why does caffeine increase heart rate?

How does temperature change affect Daphnia?

It was noticed that the Daphnia’s heart rate increased at higher temperatures (close to 34°C) and decreased at lower temperatures (close to 5°C). Since Daphnia are ectothermic, their body temperature varies with environmental temperature.

Does caffeine speed up heart rate?

Answer: Caffeine has multiple effects on the central nervous system, as well as the heart. Typically most people will experience an increase in heart rate, the degree of which differs among individuals.

Can caffeine slow heart rate?

Moderate doses of coffee have been shown to reduce resting heart rate due to a moderate increase in BP. The decrease in heart rate is generally associated with vagally mediated slowing as the baroreceptors respond to BP elevations after caffeine administration.

Why does Daphnia heart rate increase in high temperature?

How much does caffeine increase heart rate?

The receptors in the cells within your heart are stimulated by the caffeine and increases your heart rate. As your heart beats faster — accelerating by about three beats per minute — your blood flow speeds up, too.

How does cold water affect Daphnia heart rate?

If one is submerged in extremely cold water, like we did to our daphnia, it will cause the core body temperature and heart rate to drop, and this can lead to death.

How does caffeine affect the Daphnia test?

When repeating a test a different Daphnia is used. The concentration of the caffeine in the blood of Daphnia will determine the heart rate of the Daphnia. It will be directly proportional to each other, meaning that the increase of the concentration of the caffeine will give an increase of the heartbeat.

What is the concentration of caffeine in the heart of Daphnia?

Conclusion Our results show a curve of 0% concentration being higher than 0. 1% and 0. 2% concentration, this could be because of a source of error, as the graph shows a positive correlation of the increase of the caffeine percentage of concentration to the heartbeat of the Daphnia.

What factors affect the validity of a Daphnia experiment?

This also affected the validity as there could have been more than one variable working on the daphnia but in this experiment there was only one variable that was being changed: the concentration of caffeine solution. The fact that this experiment tried to stop all the other variables from affecting it, it makes it a fair test and therefore valid.

Is it possible to test synergism between Daphnia and Caff?

Please, correct the terminology of synergism or other experiments should be done using the combination of sub-threshold doses of DA and Caff. It would be very important to add positive controls to test Daphnia’s heart rate, for example, noradrenaline or atropine, both are prototypical substances that increase heart rate in vertebrate animals.