What Is The Effect Of Caffeine Of The Heart Rate Of Daphnia?

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What Is The Effect Of Caffeine Of The Heart Rate Of Daphnia             

Ross Kalarus

Candidate Number: 3052

Daphnia is a small freshwater crustacean; these creatures are known as water fleas they have no physiological way of regulating their body temperature, this means once the temperature of the environment they are in changes their body temperature changes.  The carapace of daphnia is translucent which makes them excellent subjects for this experiment as with a microscope you can see the heart.

Anatomy of a Daphnia

1.

In humans caffeine acts as a stimulant as it increases the amount of stimulatory neurotransmitters which are released. Some neurotransmitters released are norepinephrine and adrenaline which are the neurotransmitters that are involved in ‘Fight or Flight’ response which is directly involved with increasing heart rate. Caffeine is found in many sources in modern society such as coffee, tea, sports drinks and some chocolates.

 High levels of caffeine intake have been linked to restlessness, insomnia and anxiety, this can cause to raised stress and blood pressure. This can lead to heart and circulatory problems. A picture of the structure of caffeine can be seen below. The chemical formula of caffeine is (C8H10N4O2).

  2.

Hypothesis:

Caffeine increases the amount of neurotransmitters released which increase heart rate, so as the caffeine solution increases so will the rate of heart beats per minute in the daphnia.

I predict that the daphnia in the caffeine solution will have an increased amount of beats per minute when compared to the daphnia in distilled water. This will happen as caffeine is a stimulant which will increase the amount of neurotransmitter released increasing the rate of beats per minute.  

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Apparatus:

Daphnia, Caffeine solutions, Distilled water, Microscope, Cavity slide, Pipettes, Wax or Vaseline,  Petri dish and Measuring cylinder, Filter paper.

Plan:

The variables in this experiment are:

Caffeine concentration as the independent variable. The heart rate of the daphnia as the dependant variable. The controlled variables are temperature, sample size of the daphnia, volume of caffeine solutions and the stress levels of the daphnia.

A risk assessment has shown that as the caffeine and distilled water are going to be contained in glass beaker they could be dropped and smash, these glass splinters may then cut or pierce the ...

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