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

Effect of Ethanol on the Daphnia heart rate

Extracts from this document...


Effect of Ethanol on the Daphnia heart rate In this experiment we will be looking at the effects of different concentrations of ethanol on the heart rate of the water flea, Daphnia. This small freshwater crustacean is relatively transparent; this allows their heart rate to be recorded clearly by simply observing them through the microscope. The experiment consists in preparing 5 different environments to put the water flea in, and observe how the heart rate responds to each change; the change will be the increase of ethanol concentration %. This will be the independent variable. The dependent variable is the heart rate of the Daphnia. The materials needed to perform this experiment are the following: * Normal size syringe * 2 Small syringes (must have units of measurement) * Open top pipette * Ethanol of 1% concentration * *Various Daphnia to perform experiment on * Microscope * 6 Petri dishes * Cavity slide * Marker * Paper * Stop watch * Distilled water * Labels *Before performing the experiment you will have to go to a pond or lake, and acquire a significant amount of water fleas and place them in a glass or container in water from the pond or lake. ...read more.


Multiply this number by four; this gives you the heart rate per minute. Record the result. Do this process 3 times in order to get 3 heart rates. Add the 3 heart rates and then divide the result by 3; this will give you the average of the Daphnia heart rate under those conditions. Keep the Daphnia under the microscope for a maximum of 2 minutes, because the heat of the light in the microscope could have effects on the experiment. Turn the microscope off after the count to prevent further heating caused by the light. 7. Remove the slide from the microscope, and with the normal size syringe put the Daphnia into the 0.2% labelled Petri dish (wash the slide with water and dry it). Leave the Daphnia in the Petri dish for 3 minutes once again. After 3 minutes, use the normal sized syringe to put it onto the microscope slide. Repeat step 6 and record results. 8. Count the heart rate of the Daphnia when placed in all the concentrations. Work your way up from 0% to 0.2% to 0.4%, 0.6%, 0.8%. ...read more.


They allow communication between cells to occur. Nerves can receive communication from cells far away or from nerve cells near by. Cells far away secrete hormones, which find their way to the target nerve's hormone receptors. Once these hormones attach to the receptor, changes in the nerve take place. The hormone-receptors, when activated, can change how quickly a nerve generates an impulse, or alter how fast the nerve passes impulses along. Some hormones increase heart rate and some decrease heart rate. Other receptors allow communication between adjacent nerve cells (such as between the pacemaker neurons and the follower neurons). Instead of hormones, the receptor binds to neurotransmitters. These receptors sometimes accidentally bind molecules they shouldn't. The nerve fibers conducting pulses to the hearts of Daphnia may contain receptors that inappropriately bind to the ethanol causing a decrease in activity. This process coincides perfectly with the fact that ethanol is a depressant that decreases nervous activity, partly through interfering with neurotransmitters, and in turn decreasing heart rate. In conclusion, increased levels of ethanol affect the regulation of heartbeat in Daphnia. As the concentration of ethanol increases, the heart rate decreases and patterns can be seen as to how the rate responds to changes in the environment. The Daphnia heart rate decreases in an average of 9 b/m as the concentration increases by 0.2%. ...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. Investigating the effects of temperature on the heart rate of Daphnia.

    This test was carried out with three separate daphnia and each set of results was multiplied by three, so that the calculated number of beats per minute [BPM] could be estimated for each daphnia. A quantity of daphnia were transferred to petri dish and floated in the water bath [35oC],

  2. Diabetes Type 1 and 2

    it so we do not know exactly if there is or not but we said no because it the majority said there wasn't any glucose. This test doesn't tell us exactly how much glucose is in each sample but it just simply says if t has any in it o not.

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

    * Medicine dropper - easiest and kindest way to extract the daphnia from the solution * Depression slides with slip covers - daphnia will not be crushed by cover slips * Ice bath - easiest way to reduce heart rate by cooling the daphnia * Thermometer * Goggles - keep

  2. The Effect of Substrate on

    time to allow for the yeast adjusting to its new conditions and to produce respiratory enzymes. Measuring time: The time intervals of measuring the CO2 collected will be kept the same for all repeats. The total time will be 10 minutes after acclimatisation measuring in 1 minute intervals.


    Normal distilled water could have been used as a control by monitoring the heart of a caffeine-free Daphnia, then monitoring the same Daphnia after caffeine had been added. The 10ml measuring cylinder will then need to be obtained to measure the volume of distilled water needed in each beaker.

  2. Thistles by Ted Hughes. Question: Critically analyse the poem

    R : Furthermore, it seems as though thistles began and end with the presence of blood- spac'From the underground stain of a decayed Viking' they grow and before growing spac'grey like men', 'Everyone manages a plume of blood'. Hence, this parasite-like spacebehavior gives thistles an evil character for it thrives

  1. The Effect of Activity on the Heart Rate

    The heart, cardiovascular and respiratory systems all work together to coordinate the increase in oxygen delivery needed to cope with the increased demand for energy. The human body is reliant on adenosine triphosphate (ATP) to produce energy. The body only stores very small amounts of ATP, enough to power strenuous exercise for just a few seconds.

  2. The Pick Up

    He chuckles. Time itself seems to have stilled in the darkness. From nowhere a blood-curdling screech pierces the silence as a huge, dark shape whizzes by Derek's ear. Immediately Derek drops to the ground, his heart pounding like a jackhammer.

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