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

How caffeine affects daphnia heartrate

Extracts from this document...

Introduction

Aim: How caffeine affects the heart rate of Daphnia (water fleas) During this experiment we were examining the effects of different concentrations of caffeine on a type of water fleas called daphnia; the heart-rate is the dependant variable and the concentration of the caffeine is the independent variable. We tried to keep all of the other variables constant by controlling them. Such as the room temperature; the volume of caffeine; the type of water fleas ect. Our hypothesis is that as the caffeine increases so will the heat rate of the daphnia. This is because caffeine is a stimulant that increases the amount of neurotransmitters being released and therefore the production of the heart. Equipment: * A culture of Daphnia in a beaker of water * A microscope- with two cavity slides * Two dropping pipettes- one with a large mouth and one with a small opening * Cooled Distilled water * Cotton wool * Paper towels * A stop clock Method: 1. We picked out a couple of daphnia from the culture in the beaker with the pipette that has a big mouth. ...read more.

Middle

185.67/ 186bpm Our results table for distilled water: No. Of times distilled water was added. No. Heartbeats every minute Average No. Of heart beats per minute (bpm) 1 2 3 4 5 1 169 150 172 174 170 167bpm Graph of results: 186-167 In conclusion: From my results we can tell that the relationship between the caffeine and the heart rate is that as the caffeine increases so does the heart rate. This means, caffeine ?heart-rate. This is as I predicted that this would happen because caffeine is a stimulant drug. This is true as on average the caffeine had 19 more beats per minute than no caffeine. As I mentioned before, this is because the caffeine increase the production of neurotransmitters. Neurotransmitters are the chemicals which allow the transmission of signals from one neuron to another across synapses. They are also found at the endings of motor neurons, where they stimulate the muscle fibres. This means that if the caffeine increases the amount of neurotransmitters that will then consequently increase the stimulation of the muscle fibres and that increases the activity of the heart; causing the heart to beat faster than normal. ...read more.

Conclusion

and therefore its average is not as reliable as we would have liked. To make sure our results we valid we tried to control all the other variables other than the concentration of the caffeine (all which I stated in the introduction). This includes the temperature of the daphnia. It must be understood that the daphnia are living organisms and need to be treated right in the experiment. So, to look after and keep them cool we put the cool water underneath the slide they were on. Another thing we done was when we were not using them we took them out from under the hot light of the microscope so that they would not burn. If I were to do this experiment again I would make sure that I had enough time to repeat both experiments more times to make it more reliable. Also, I would use some kind of data logger to measure the heartbeat of the daphnia; this would eliminate the chance of human error. To make it even more valid I would try to use the same daphnia each time and use a thermometer to see the temperature so it would be easier for be to regulate it. ?? ?? ?? ?? 1 Awo Mahad 12ND How caffeine affect the heart-rate of Daphnia ...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)

This is a well written report.
1. The start of the report is quite brief and is missing several sections, such as a safety section.
2. The tables of data are well presented.
3. The conclusion should use data from the tables to back up the patterns and should also refer to the graph.
4. The evaluation should suggest further research opportunities.
***

Marked by teacher Luke Smithen 23/07/2013

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)

    Potentially 3 molecules of ATP can be produced from each reduced NAD molecule. However about 25% of the total energy yield of electron transfer is used to transport ADP in to the mitochondrion and ATP into the cytoplasm. Therefore each reduced NAD molecule yields the equivalent to two and a

  2. Marked by a teacher

    An investigation into the effect of different sugars on respiration in yeast.

    5 star(s)

    * Use the ratio of 15:5 (yeast: sugar) throughout. * After placing the bung in the boiling tube and starting the stop clock, place the boiling tube in the water bath. * Do not shake. * Record the level on the burette after every minute for 10 minutes.

  1. Marked by a teacher

    Effect of nitrate concentration on the growth of Duckweeds

    5 star(s)

    duckweeds on the tile without water this could lead to the weeds drying out, and become damaged easily, due to it's small size and as I was finding quite a large number of particular shaped weeds which took me a quite a long time.

  2. Marked by a teacher

    To make sure we have plenty of energy in the future, it's up to ...

    4 star(s)

    About 30 percent of the world's wind-generated electricity are found in California. Other countries that use a lot of wind energy are Denmark and Germany. But once electricity is made, it has to get from the wind turbines to our homes, factories and schools.

  1. Marked by a teacher

    Measurments of boby temperature, heart rate and breathing rate

    3 star(s)

    my results it told me it was 36 and again after 3 minute it was 28 and at last 4 minutes it came back down to 20. The last experiment we done was checking body temperature. It was quite difficult for us to see the results on the thermometer as they were very close to each other.

  2. Describe the concept of homeostasis and the homeostatic mechanisms that regulate heart rate, breathing ...

    Roles of the skin in control of the body temperature- roles of arterioles and sweat glands. Arterioles: When a person has high body temperature the arterioles are widened and because of this blood flows through very easily allowing the blood to go through to all parts of the body

  1. Cycles in Biology.

    Untreated, or partially treated, domestic sewage is another major source. Sewage was a particular source of phosphorus to lakes when detergents contained large amounts of phosphates. The phosphates acted as water softeners to improve the cleaning action, but they also proved to be powerful stimulants to algal growth when they were washed or flushed into lakes.

  2. Effects of exercise on tidal volume and breathing rate

    In the elastic tissues of the lung and the chest wall are receptors that respond to stretch. There are also stretch receptors in the blood vessels in the lung. If these are stretched, as in heart failure, the response is to hyperventilate.

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