What factors affect the heart rate of Daphnia?

What factors affect the heart rate of Daphnia?

Daphnia is poikilothermic, which means that its body temperature and therefore the temperature of the environment directly affects its metabolic rate. The change in metabolic rate is reflected in the rate at which the heart beats (cardiac frequency).

How does caffeine affect the heart rate?

Caffeine affects the heart in multiple ways. Firstly, it promotes the release of noradrenaline and norepinephrine. Among other things, these hormones increase heart rate and blood pressure. Additionally, caffeine can act on enzymes that stimulate heart contractions, causing the heart to contract with more force.

Why did alcohol and caffeine have differing effects on the heart rate of the Daphnia?

Due to these effects, we believe the presence of nicotine and caffeine in water containing Daphnia Magna will result in an increased heart rate of the Daphnia Magna, while ethanol will do the opposite and decrease the heart rate of the Daphnia Magna because caffeine and nicotine will activate neurotransmitters that …

How much caffeine kills a Daphnia?

When 236.59 ml of Monster energy drink was added to a liter of spring water, the resulting solution killed the daphnia. Their deaths may have been the result of too much caffiene or another chemical contained in Monster energy drink. The scientist proved that caffeine does affect a daphnia’s heart rate.

Why does caffeine increase heart rate biology?

We hypothesized by increasing the amount of caffeine the heart rate will also increase because caffeine activates neurotransmitters that excite the body which then increases heart rate. Our study system included each Daphnia used in each specific trial, the two concentrations of caffeine, and the plain water solution.

How does caffeine affect heart rate a level biology?

In humans, caffeine is a ​stimulant​which increases heart rate by​ increasing release​of excitatory neurotransmitters.

Does caffeine decrease 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.

Does caffeine cause rapid heartbeat?

Rapid Heart Rate The stimulatory effects of high caffeine intake may cause your heart to beat faster. It may also lead to altered heartbeat rhythm, called atrial fibrillation, which has been reported in young people who consumed energy drinks containing extremely high doses of caffeine ( 39 ).

What is 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 Daphnia heart rate increase with temperature?

Since Daphnia are ectothermic, their body temperature varies with environmental temperature. Since Daphnia cannot thermoregulate, their body temperature experiences variance following fluctuations in the environment (Ziarek et al. 2010). Hence as the temperature of the water increased, so did the Daphnia’s heart rate.

Why does caffeine increase heart rate a level biology?

Can caffeine cause rapid heart rate?

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.