• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

How does caffeine affect the heart rate of Daphnia?

Extracts from this document...

Introduction

´╗┐Mohamed Ahmed Does caffeine affect heart rate? The purpose of this experiment is to investigate the effect of caffeine on the heart rate of Daphnia (water fleas). Daphnia are tiny aquatic invertebrates that are suitable for this experiment because they?re abundant, easily obtained, transparent and have very simple nervous system. Hypothesis: I think that a Daphnia subjected to a caffeine solution will show a rise in heart rate, this rise in heart rate should reflect the concentration of caffeine in a given solution. This is because caffeine is a stimulant that speeds up the body affecting the nervous system and rate in which the nerve pulses are sent and received in humans. I produced a detailed plan for an experiment that allowed me to test my hypothesis using the following materials: 1. Pipettes 2. Test tubes 3. Stop clock 4. Microscope 1. Daphnia 2. Cavity slides 3. Distilled water 4. ...read more.

Middle

We will handle cavity slides and test tubes carefully to prevent breakage 2. Be cautious not to touch the lamp with wet hands since it uses electricity 3. Be careful not to spill any of the testing solutions on the floor. There are some ethical issues involved in using these invertebrates. Many people believe that it?s unethical to cause distress or suffering to any living organism - e.g. by subjecting them to extremes of temperature or depriving them of food. I will take this into account whilst doing my experiment by not putting the microscope on a high power. Some people believe it?s more acceptable to perform experiments on invertebrates (like Daphnia) than vertebrates (like dogs and monkeys). This is because they?re considered to be simpler organisms than vertebrates. For example they have a much less sophisticated nervous system, which could mean that they feel less pain (or no pain). ...read more.

Conclusion

To determine the heart rate, the beats are counted in pulses under a microscope and recorded using a hand counter. This is accurate; however a margin of systematic error should be accounted for in the results. We will make sure measurements are precise and accurate by making the tests repeatable. Results Concentration of Caffeine Solution (%) Daphnia?s pulse counted in 20 seconds (x3 for 1 min) Daphnia?s pulse counted in 20 seconds (x3 for 1 min) Test 1 Test 2 0 54 51 0.1 75 72 0.2 108 102 0.3 135 138 0.4 192 180 0.5 261 237 Conclusion ? I stated in my hypothesis that I think that a Daphnia subjected to a caffeine solution will show a rise in heart rate. The results obtained by my group and I indicates that my hypothesis was correct because the more concentrated the caffeine solution was, the higher the heart rate of the daphnia; at 0.1 % caffeine solution the mean heart rate of the Daphnia was 53 beats per minute; with 0.3 % caffeine solution the mean heart rate of the Daphnia was 173 beats per minute. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Energy, Respiration & the Environment section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related AS and A Level Energy, Respiration & the Environment essays

  1. Marked by a teacher

    Effect of nitrate concentration on the growth of Duckweeds

    5 star(s)

    Nitrogen is used in the manufacture of the nitrogenous co- enzyme NADP, it also in the energy used as ATP, as it contains the nitrogenous base Adenine. These two components need nitrogen to be taken in, in order to be produced. They are also the most important components for survival.

  2. Marked by a teacher

    How caffeine affects Daphnia heartbeat?

    4 star(s)

    0.5 132 3 0 274 0.1 287 0.5 not done 0 52 4 0.1 148 0.5 432 Average of practical results with anomalies Concentration of caffeine Average Average beats per minute 0 120 + 109 + 274 + 52 / 4 139 0.1 140 + 120 + 287 + 148

  1. Marked by a teacher

    AS Edexcel Biology - Aim: To investigate the effect of caffeine on the heart ...

    3 star(s)

    Conclusion Having carried out this experiment fully, I am able to conclude that there is a correlation between the concentration of caffeine and the average beats per minute, the average beats per minute increases when the concentration of caffeine increases.

  2. Investigate the effect of bile salt concentration on the digestion of milk by the ...

    This meant that the reactants were not being heated constantly and so to get the temperatures to agree was difficult and they often fluctuated. Also while setting up the experiment the temperatures cooled down and so were not always at 36OC.

  1. the effect of bile concentration on the activity of the enzyme lipase during the ...

    Consequently the information that is presented on this website must be reliable and accurate since the university must check the information it publishes on its website to make sure its accurate. * http://en.wikipedia.org/wiki/Enzyme - Used for background information on enzymes.

  2. Investigate the effect of changing the sugar concentration on the rate of respiration of ...

    During my experiment there were some minor problems I encountered, however, these did not effect my results as they were minor set backs, which I was able to easily sort out. Firstly, once I had poured the hot water into the beaker, it was at 40(, but as the test

  1. Investigating how prolonged exposure to its optimum temperature affects the respiration of yeast.

    so more than likely of ten minutes exposure or less, so the yeast has enough time to reach the temperature of the water bath..." This seems like the most logical explanation for the graph. It would have been expected that the correlation of the graph was either negative or positive

  2. Investigation into the Effect on Pulse Rate & Breathing Rate During

    The heart rate will always increase when special demands are placed upon it, such as exercise. Since faster blood flow increases the rate at which fresh blood reaches the body cells, more oxygen and glucose are made available to them during periods of stress.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work