In this experiment, caffeine was used to determine the increase in heartrate, when increasing the amount of concentration. Caffeine was used on a water flea known called daphnia, to see the outcome. The results show that an increase of caffeine concentration increases the heartrate of the daphnia. ...
BTEC LEVEL 3 APPLIED SCIENCE
UNIT 6: INVESTIGATIVE PROJECT
HAJRAH ALI - 40157986
SCIENTIFIC REPORT
SABIKA KIRMANI
UXBRIDGE COLLEGE
, THE EFFECT OF CAFFEINE ON THE HEART RATE OF DAPHNIA.
ABSTRACT
In this experiment, caffeine was used to determine the increase in heartrate, when increasing the amount of
concentration. Caffeine was used on a water flea known called daphnia, to see the outcome. The results show that
an increase of caffeine concentration increases the heartrate of the daphnia. This was tested by the daphnia being
observed underneath the microscope. This technique was shown to be an effective way of analysing the heartrate,
this would mean that the same effect is also opposed in humans. In conclusion the effect of caffeine on the heart
rate of daphnia increased as I increased the concentration of caffeine. This supported by hypothesis as caffeine being
a cardiac stimulant and the response given by the nervous system as nerve impulses are received much more
quickly.
INTRODUCTION
The different concentrations of caffeine on the heart rate of daphnia was investigated to see how it impacts the
human heart when the concentration of caffeine is increased. Does the heartbeat stay consist, drop, or
increase? This experiment should find that with an increase of concentration given to the daphnia the rate of the
heartbeat should also increase.
The investigation will be carried out on water fleas called Daphnia; these are small transparent fleas which are
known as substitutes of humans, this will be easy to measure as we will be able to see the heart beating. Cleveland
Clinic (2018) [1]. The different substances used will allow us to see a similar effect in oppose to the human heart.
Studying the effect of caffeine on daphnia opposed to human because daphnia is a transparent water flee which
does not require us to open create any incisions to see the heart whereas humans are opaque make it difficult to
watch the heart and would require incisions to the body. (UKEssays.com, 2018) [7]. They reproduce asexually which
means they don’t have threat to the reproduction, as too much caffeine in humans can have a different effect which
can endanger them this also means that daphnia have no loss in their genetic variation. Daphnia have a less
developed nervous system which enables them to feel less pain as they have reduced awareness compared to a
human.
Caffeine helps restore mental alertness. It is a stimulant derived from plants which use it as an insecticide to paralyze
or kill insects which attempt to feed on them, such as leaves, seeds or fruit such as coffee beans, tea leaves and
bud's bola nuts, cocoa beans, guarana seeds and yerba leaf. (Salters-Nuffield Advanced Biology Resources Activity
1.27 Student Sheet Core Practical DOES CAFFEINE AFFECT HEART RATE?, 2015) [5]
HYPOTHESIS
I hypothesized when increasing the amount of concentration of caffeine to the Daphnia, I will see an increase in
heart rate due to caffeine activating and exciting the body. I will be analysing the heartrate of the daphnia and will
be seeing the caffeine has an increase or decrease effect. I think that the heartrate will increase as caffeine is
stimulant, spiking the daphnia with energy.
MATERIALS
Daphnia: The Daphnia was used to test the rate of heart.
Cavity slides: These were used as they have a dense spot in the middle so that it can hold the concentration and
the daphnia.
Optical Microscope: An optical microscope is used to observe, the heart of the daphnia so that we can count it as
daphnia are small fleas which the heart cannot be seen using the naked eye.
Dropping Pipettes: pipettes were used to pick up the concentration and daphnia and to mix the dilutions of
caffeine.
Distilled water: This was used as a control at the beginning of the investigation and was also used to make the
dilutions of caffeine concentration.
Caffeine concentrations: (0.2M,0.4M,0.6M,0)
Cotton wool: Was used so that the daphnia stays in a fix position under the microscope and is secure.
Stop clock: This was used to keep time of my repeats of counting the heart rate.
Filter paper: Was used to absorb any excess water around the cavity slides.
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