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

AS Edexcel Biology - Aim: To investigate the effect of caffeine on the heart rate of Daphnia (water fleas).

Extracts from this document...

Introduction

The effect of caffeine on heart rate. Aim: To investigate the effect of caffeine on the heart rate of Daphnia (water fleas). Background Information: Plants produce caffeine as an insecticide. Cocoa in South America, coffee in Africa and tea in Asia has all been used as 'pick-me-up' drinks containing caffeine. These days caffeine is used in a wide variety of soft drinks such as cola to enhance flavours. In addition to this, stimulant drinks such as Red Bull and Boost also carry high levels of caffeine as well as some weight-losing drugs and medicines such as Aspirin. IN humans, caffeine acts as a stimulant drug, causing increased amounts of stimulatory neurotransmitters to be released. At high levels of consumption caffeine has been linked to restlessness, insomnia and anxiety, causing raised stress and blood pressure. This can lead to heart and circulation problems. Hypothesis: I think that the Daphnia's heart rate will rapidly increase when the caffeine solution is added. ...read more.

Middle

2. Stopwatch - So I measure the heart rate of each Daphnia with caffeine solutions for the same period of time (1 minute) 3. Cavity Slide - So I can hold the Daphnia in a small area so it cant move away from me when trying to measure the heart rate. 4. Strands of Cotton Wool - So I can prevent the Daphnia from moving fully when it reacts with the caffeine solution. 5. Pipette - So I can accurate collect one Daphnia needed and the correct levels of water and caffeine. 6. Glass Beakers - This is so I can have the correct measurements of water and caffeine concentration. Results: Beats per minute. Concentration of Caffeine Test 1 Test 2 Test 3 Average beats per minute Control (no caffeine) 128 131 132 130.3 0.1 122 120 140 127.3 0.2 132 134 144 136 0.3 148 152 160 153.3 0.4 169 152 160 160.3 0.5 162 172 168 167.3 Table showing all the results obtained during the experiment plus the averages of beats of the Daphnia per minute for each concentration of caffeine. ...read more.

Conclusion

This has allowed me to gather more data than many of my fellow experimenters and so I am therefore able to have a more detailed conclusion with more evidence to back it up. Because of this reason alone I am pleased with how the experiment went. Furthermore I am able to say that there are no anomalies. This is good because it means all of my results are reliable and therefore my conclusions that I've drawn are valid. The one improvement I would make next time is to only time the heart rate for 30 seconds and then double the heart rate after that time to make it one minute. This is because I found it hard to constantly focus for a minute on the heart rate and could sometimes lose count and need to start over again. For an extended project of this practical experiment I believe it would be interesting to find out if substitutes for caffeine and similar products have the same effect as caffeine on the heart rate of Daphnia. ?? ?? ?? ?? Sam Lingwood Biology Practical Investigation ...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

Here's what a teacher thought of this essay

3 star(s)

Quite a good overall account of the investigation but analysis of the results could have been more critical, and plotting of wrong graph is a major error.

Marked by teacher Adam Roberts 11/04/2013

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 temperature on the rate of respiration in yeast

    5 star(s)

    This also changes into 4 carbon chain fumarate. Then this changes into malate and this releases from NAD+ to NAD+ + H+. Then this again changes into oxaloacetate and starts the cycle again. After the cycle is been round six times it releases 1 glucose molecule.

  2. Marked by a teacher

    Biology coursework investigation: Comparing the length of ivy leaves (Hedera helix) in areas of ...

    4 star(s)

    Each leaf will be measured twice to minimise the chance of inaccurate measurements. The concentrations of CO2 and O2 will affect the rate of photosynthesis in the ivy plants but as both are located close to each other; it is likely that the concentration of gases will be the same.

  1. Free essay

    Biological Importance of Water

    3 star(s)

    Water based lubricating fluids within the body include: * Mucus - This is used externally to aid movement in animals, such as in snails, or internally on the gut wall to aid the movement of food. * Synovial fluid - This lubricates movement in joints.

  2. What effect does substrate have on respiration in yeast?

    Dependent variable is the factor that is being measured and it changes according to the independent variable. In this investigation, the dependent variable would be the carbon dioxide production. The volume of carbon dioxide produced should be different for each substrate due to the reasons explained in the prediction.

  1. Daphnia Investigation

    that there is a direct relationship between the concentration of caffeine and the heart rate of Daphnia. Conclusion My hypothesis and prediction were correct. From the results gathered, and the consistant trends on the graphs, it can be concluded that an increase in caffiene concentration produces an increase in heart rate.

  2. Cycles in Biology.

    Gradually, every part of an organism decomposes and returns to the Nutrient Cycle. Water is a molecule made of two atoms of Hydrogen (H) and one atom of Oxygen (O). Its chemical formula is H2O. Water is reused over and over again.

  1. The Effect of Caffeine on Daphnia Heart Rate

    The independent variable is the percentage of caffeine concentration the Daphnia are submerged into for 2 minutes. The dependant variable in the Daphnia heart rate. Method 1. place cotton wall on a cavity slide. This helps to restrict the movement of Daphnia 2.

  2. Effects of exercise on tidal volume and breathing rate

    The information from these receptors in the lung is carried to the respiratory centre along the vagus nerve. Null hypothesis There will be no significant difference in the tidal volume or breathing rate of a subject between rest and exercise Hypothesis The tidal volume and breathing rate of a subject

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