Literature Review for 6A
Caleb Watson
Scenario: I work in a research and development lab. My supervisor has decided it is time for me to
manage my own project. I will choose an investigative project based on advice from my supervisor
and my own interest within the field of chemistry, biology or physics. I will present a project
proposal to my supervisor. My presentation will be supported by notes in a logbook.
I have chosen to investigate the effects of caffeine on Daphnia. My supervisor has agreed to allow
me to perform this investigation.
Hypothesis:
According to secondary research I have studied, when daphnia are given caffeine, their heart rate
increases at a measurable rate. Our independent variable is caffeine, and our dependent variable is
the heart rate of the daphnia. My hypothesis is that the heartrate of daphnia increases with the
intake of caffeine. Another substance that I am including, ethanol, lowers the heart rate of daphnia,
according to secondary research. Our independent variable is the ethanol, and our dependent
variable is the heart rate of the daphnia. My hypothesis is that the heartrate of daphnia decreases
with the intake of ethanol.
Aims:
I am aiming to prove that an administration of caffeine on daphnia has a close-to-immediate positive
effect on its heartrate, along with proving that an administration of ethanol on daphnia has a close-
to-immediate negative effect on its heartrate.
What are Daphnia?
According to Wikipedia, “Daphnia is a genus of small planktonic crustaceans, 0.2–6.0 mm in length.
Daphnia are members of the order Anomopoda, and are one of the several small aquatic
crustaceans commonly called water fleas because their saltatory swimming style resembles the
movements of fleas.” “The two most commonly found species of Daphnia are D. pulex (small and
most common) and D. magna (large).” [4] This is the anatomy of a water flea:
[4]
, In the upper right region, we can see the heart above the embryo and brood chamber. On the right,
the large region that is mainly white is the 5 thoracic appendages, with the organs and anus down
the middle. The carapace (shell of a crustacean) encapsulates the thoracic appendages and extends
all the way up to near the compound eye.
Ethics behind using Daphnia:
The reason why I have chosen to experiment on Daphnia is that they are not entirely an endangered
species. There are 4 species of daphnia that are endangered under the International Union of
Conservation of Nature, but we will not be using these species. Daphnia do not contribute to the
destruction of a food chain, so in the even that they do pass away in our lab, it will be okay for the
wild. I will return them to their natural environment after concluding with my experiment. As my
investigation will not kill the daphnia, it is ethically normal for me to experiment on daphnia with
caffeine and ethanol. If I was using a substance such as bleach, it would not be ethical as that would
kill the daphnia.
The advantages of using Daphnia:
The benefits of using Daphnia hugely contribute to the ease of this investigation. Daphnia are easy to
find and are hard to kill, ensuring that I can experiment on them without them dying or becoming
motionless during the experiment. Their “thin membranes” allow for an easy absorption of drugs,
which will be caffeine in this experiment. [4] They are also easy to care for.
The disadvantages of using Daphnia:
One disadvantage of using Daphnia is the size of the crustacean. Due to its size, examining the
heartbeat under a microscope is very difficult to do with just the naked eye. When I had performed
this experiment in the past, we used the method of recording the heartbeat of Daphnia by tapping
dots onto a piece of paper when we saw a heartbeat. Due to how fast the heartbeat becomes in
Daphnia, when under caffeine, the heartbeat was too fast to record with precise accuracy.
Justification for why I have chosen to investigate the effects of caffeine on Daphnia:
Studying the effects of caffeine on daphnia is easy to perform and does not take more than a day to
carry out. Daphnia can be found at most local ponds and lakes, so acquiring daphnia is achievable,
and studying the effects of caffeine on them is easy because the lab I am working in has light
microscopes. I thought about investigating the effect of calcium on the development of Daphniids,
but I understood that this experiment would take too much time and would need to have daily
check-ins to record the size of the Daphnia’s carapace. Experimenting with caffeine and ethanol are
much easier due to the fact that we can conclude the experiment quickly, and we do not have to
record results over various days or weeks. My literature review supports this as it states that
experimenting the effects of caffeine and ethanol on just one daphnia can be set up and performed,
and the results can be recorded in less than a few minutes. Lastly, when I ran this over with my
supervisor, he was certain that this investigation was appropriate for my research project.
My investigation will be done over short period of time (8 days total, 6 days of experimentation) due
to the fact that temperatures can affect the heartbeat of the daphnia. This is shown in my literature
review where temperature has affected the heartbeat.
Caleb Watson
Scenario: I work in a research and development lab. My supervisor has decided it is time for me to
manage my own project. I will choose an investigative project based on advice from my supervisor
and my own interest within the field of chemistry, biology or physics. I will present a project
proposal to my supervisor. My presentation will be supported by notes in a logbook.
I have chosen to investigate the effects of caffeine on Daphnia. My supervisor has agreed to allow
me to perform this investigation.
Hypothesis:
According to secondary research I have studied, when daphnia are given caffeine, their heart rate
increases at a measurable rate. Our independent variable is caffeine, and our dependent variable is
the heart rate of the daphnia. My hypothesis is that the heartrate of daphnia increases with the
intake of caffeine. Another substance that I am including, ethanol, lowers the heart rate of daphnia,
according to secondary research. Our independent variable is the ethanol, and our dependent
variable is the heart rate of the daphnia. My hypothesis is that the heartrate of daphnia decreases
with the intake of ethanol.
Aims:
I am aiming to prove that an administration of caffeine on daphnia has a close-to-immediate positive
effect on its heartrate, along with proving that an administration of ethanol on daphnia has a close-
to-immediate negative effect on its heartrate.
What are Daphnia?
According to Wikipedia, “Daphnia is a genus of small planktonic crustaceans, 0.2–6.0 mm in length.
Daphnia are members of the order Anomopoda, and are one of the several small aquatic
crustaceans commonly called water fleas because their saltatory swimming style resembles the
movements of fleas.” “The two most commonly found species of Daphnia are D. pulex (small and
most common) and D. magna (large).” [4] This is the anatomy of a water flea:
[4]
, In the upper right region, we can see the heart above the embryo and brood chamber. On the right,
the large region that is mainly white is the 5 thoracic appendages, with the organs and anus down
the middle. The carapace (shell of a crustacean) encapsulates the thoracic appendages and extends
all the way up to near the compound eye.
Ethics behind using Daphnia:
The reason why I have chosen to experiment on Daphnia is that they are not entirely an endangered
species. There are 4 species of daphnia that are endangered under the International Union of
Conservation of Nature, but we will not be using these species. Daphnia do not contribute to the
destruction of a food chain, so in the even that they do pass away in our lab, it will be okay for the
wild. I will return them to their natural environment after concluding with my experiment. As my
investigation will not kill the daphnia, it is ethically normal for me to experiment on daphnia with
caffeine and ethanol. If I was using a substance such as bleach, it would not be ethical as that would
kill the daphnia.
The advantages of using Daphnia:
The benefits of using Daphnia hugely contribute to the ease of this investigation. Daphnia are easy to
find and are hard to kill, ensuring that I can experiment on them without them dying or becoming
motionless during the experiment. Their “thin membranes” allow for an easy absorption of drugs,
which will be caffeine in this experiment. [4] They are also easy to care for.
The disadvantages of using Daphnia:
One disadvantage of using Daphnia is the size of the crustacean. Due to its size, examining the
heartbeat under a microscope is very difficult to do with just the naked eye. When I had performed
this experiment in the past, we used the method of recording the heartbeat of Daphnia by tapping
dots onto a piece of paper when we saw a heartbeat. Due to how fast the heartbeat becomes in
Daphnia, when under caffeine, the heartbeat was too fast to record with precise accuracy.
Justification for why I have chosen to investigate the effects of caffeine on Daphnia:
Studying the effects of caffeine on daphnia is easy to perform and does not take more than a day to
carry out. Daphnia can be found at most local ponds and lakes, so acquiring daphnia is achievable,
and studying the effects of caffeine on them is easy because the lab I am working in has light
microscopes. I thought about investigating the effect of calcium on the development of Daphniids,
but I understood that this experiment would take too much time and would need to have daily
check-ins to record the size of the Daphnia’s carapace. Experimenting with caffeine and ethanol are
much easier due to the fact that we can conclude the experiment quickly, and we do not have to
record results over various days or weeks. My literature review supports this as it states that
experimenting the effects of caffeine and ethanol on just one daphnia can be set up and performed,
and the results can be recorded in less than a few minutes. Lastly, when I ran this over with my
supervisor, he was certain that this investigation was appropriate for my research project.
My investigation will be done over short period of time (8 days total, 6 days of experimentation) due
to the fact that temperatures can affect the heartbeat of the daphnia. This is shown in my literature
review where temperature has affected the heartbeat.
