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

My hypothesis is that with an increase in temperature a Daphnia's heart rate willincrease.

Extracts from this document...

Introduction

HEFC BIOLOGICAL SCIENCE - UNIT 2 Joseph Colledge ASSESSED PRACTICAL VARIATION OF DAPHNIA HEART BEAT WITH TEMPERATURE a) My hypothesis is that with an increase in temperature a Daphnia's heart rate will increase, likewise with a reduction in temperature the heart rate will decrease. This is due to the Daphnia being an ectothermic organism, so its body heat is determined by its environment, namely that their body temperature is the same as the water they are floating in. Thereby having a direct effect on its metabolic rate. b) A Daphnia was taken via a teat pipette from a beaker of room temperature water (Measured at 20?C) and placed onto a cavity slide, this was then placed under a microscope. The heart was then located via the use of diagrams and confirmation sought by a person who had previously carried out the experiment. It was then decided that to get the most accurate results a group of 2 people would be most efficient, one person would be responsible for counting the beats per minute whilst the other would govern the time. ...read more.

Middle

This was to be carried out at 5 different temperatures and the average bpm results documented. c) Table to show how temperature effects the heart rate of a Daphnia Temperature ?C Heartbeats Per Minute 2 100 10 135 16 180 20 210 32 480 Joseph Colledge d) The results show that due to the Daphnia being Ectothermic (cold-blooded) and therefore not able to thermo-regulate itself, the temperature of the water in which it habituates has a direct effect on its heart rate. The reason for this is that the chemical reactions that occur in the Daphnia are dependent on certain enzymes, or proteins to help them proceed. As the temperature of the water is increased, the metabolism of the Daphnia increases also; this is due to chemical reactions occurring faster at higher temperatures due to an increase in kinetic energy. As a consequence of this increase, the heart has to beat faster as more Carbon Dioxide is produced from the cells during respiration. This can cause acidic conditions which will eventually denature enzymes, so more oxygen needs to circulated which is why the heart speeds up. ...read more.

Conclusion

It would also greatly change the amount of bpm if the Daphnia were pregnant and that was very hard to determine. Another would be the amount of stress, which the Daphnia is placed under during the experiment. The final error is the fact that in some cases the Daphnia being used would die and another used to carry out the remainder of the experiment, which would invalidate previous heart rates. f) To improve the experiment I would suggest that natural light was used for the microscopes rather than lamps to reduce heat. Another way to improve it would be to film the beats of the heart with a video camera then play them back in slow motion to get a more accurate count. Getting a person who is experienced with them to say whether it's a male/female would give more accurate results also. Also if a Daphnia dies during the experiment it would be more accurate to just start again rather than continuing with the same results from the previous one. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Humans as Organisms 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 GCSE Humans as Organisms essays

  1. To investigate how the heart rate and breathing rate increase with exercise.Scientific KnowledgeAerobic respiration ...

    8 24 66 12 30 78 12 24 78 20 30 90 20 24 90 30 36 102 30 24 96 60 42 132 60 30 138 Resting HR 70 Resting HR 60 Resting BR 24 Resting BR 12 Step ups per min BR HR Step ups per min BR

  2. Investigating The Effect Of Drugs On the Heart Rate of a Daphnia.

    Receptors work by transferring energy into electrical energy. This is used to send an impulse along the nerve fibres to your brain or spinal cord. Other receptors are touch receptors in your hands are sensitive to movement, and smell receptors are sensitive to chemical energy.

  1. Effect of Ethanol on the Daphnia heart rate

    It is possible for the Daphnia to die during these tests; this is why you must have acquired a fair amount of Daphnia, in order to have back-ups. 9. Repeat this experiment once or twice with different Daphnia, in this way you will be able to analyse any trends present in the experiment more accurately.

  2. The Effect of Temperature on the Q10 of Daphnia.

    By increasing metabolic rate, these creatures can generate enough heat to keep their body warmer than their environment. Examples of endotherms would be mammals, birds and insects (1). An advantage of being an endotherm is having a high and stable body temperature as well as increased levels of aerobic metabolism (cellular respiration.)

  1. Coursework on the heart rate of the daphnia

    For a non-enzymic controlled reaction, the general rule is the higher the temperature, the faster the reaction. The same rule is true for a reaction catalysed by an enzyme, but only up to about 35�C. the heart rate is at its fastest as this is when the enzymes are working

  2. The effect of caffeine concentration on the heart rate of Daphnia.

    Also the more replicates taken the more chance there was to have of spotting a potential inaccuracy or anomaly in the results. N.B. The Independent variable is the concentration of the caffeine and the dependent variable is the heart rate.

  1. Investigating the effects of temperature on the heart rate of Daphnia.

    By slowing the movements of the daphnia down the heart rate can be determined without unduly stressing the daphnia. Using the pipette a daphnia was removed from the beaker and placed on a cavity slide; the daphnia still had some water around it, so the temperature was maintained, a cover slip was placed on top.

  2. The Effect of Caffeine on the Heart Rate of Daphnia.

    This is because the caffeine actually blocks the adenosine (form in which broken down glucose energy is stored) receptive sites on the heart muscle cells causing an increase in heart rate. Another reason is that caffeine inhibits the production of an enzyme called cyclic nucleotide.

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