• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month
Page
  1. 1
    1
  2. 2
    2
  3. 3
    3
  4. 4
    4
  5. 5
    5
  6. 6
    6
  7. 7
    7
  8. 8
    8
  9. 9
    9
  10. 10
    10
  11. 11
    11
  12. 12
    12

Daphnia project.

Extracts from this document...

Introduction

KIERON HARPER DAPHNIA PROJECT Introduction One of the most common inhabitants to be found in lakes, ponds and quiet streams are Daphnia (Also known as the water flea). Daphnia are usually less than 3mm in size and are closely related to Crab and Shrimp, and therefore a crustacean. Daphnia are commonly so called "Water Fleas" due to there erratic jumpy swimming motion through the water, caused through there second antenna being thrust downwards. Daphnia are vital elements of the food chain in fresh water areas, as they are a staple diet of small and large fish alike, and keep the water clear as part of the vital plankton feeding community. Daphnia feed on bacteria, yeast, micro-algae, detritus, and other organic matter. Their limbs draw water, which contain food particles towards their mouths. Before being swallowed the food passes through sticky mucus in the mouth entrance, which is used to mesh the food. Daphnia are predominately asexual; therefore population is usually made up of females, who asexually reproduce. They can produce broods every two - three days, with more than one hundred eggs per time. It is possible for one female too have up to twenty-five broods in a lifetime. They can also sexually reproduce under adverse conditions, in such times males are produced and sexual reproduction ensues. High population growth, low temperatures, low oxygen supply or lack of food brings about this type of sexual reproduction. The result of this being, the laying of resting eggs, similar to brine shrimp. A daphnia is a cold-blooded organism, also known as ectothermic, which means its survival is based on its surroundings. ...read more.

Middle

Place another cover slip over the top making sure the Daphnia are unharmed. 3. Place the cover slips under the water in the Petri dish. 4. Place the Petri dish on the stage of the microscope and look at the Daphnia. 5. Find the heart of the Daphnia and practice counting heartbeats. 6. Measure the temperature of the water accurately and count the heart rate for one minute using the calculator in the aforementioned manor. 7. Draw off some of the water and add water of temperature 200C. 8. Once the water has been mixed, measure the temperature again to make sure it's correct. Count the heart rate again. 9. Repeat the above steps again incrementing the temperature by 50C until it reaches 350C. Risks There are several factors that can alter the health of Daphnia and may even cause them to die. These include: * Oxygen. Daphnia can survive in poor water conditions. They have the ability to make haemoglobin, which enables them to survive in an oxygen poor environment. * pH &Ammonia. Daphnia need the pH of the water to be between 6.5 and 9.5. High Ammonia and pH will reduce the levels of reproduction, but will not actually cause any harm to the Daphnia. * Minerals. Daphnia are very sensitive to the composition of their environment. Salts such as sodium, potassium, magnesium and calcium can cause the Daphnia to become immobile and they will eventually die. Variables There are several factors, which need to be taken into account whilst studying the Daphnia: * Firstly the oxygen levels must be kept constant, to prevent the Daphnia from suffocating. ...read more.

Conclusion

The impact of these factor, cause me to doubt the validity of my results. I would like to repeat this experiment several times taking into account these additional points: * The use of microscopes which did not omit heat * Use a higher powered microscope * Use Vaseline to keep the daphnia still With these points taken into consideration and the opportunity to repeat the experiment several times, would I be totally confident in my results and findings. Only with the repetition, can an experiment be truly validated. The Daphnia as an ectothermic organism which uses its surroundings to regulate body temperature, would in its natural habitat, be able to cool down by travelling to the bottom of its body of water. Thus in turn, keeping its body at its optimum temperature. In this experiment the Daphnia could not escape the heat as it was confined to the Petri dish, and had to use different ways to cool down. This led to the increase in heart rate as the Daphnia produced a lot of energy as it fought to bring its body temperature under control. Overall I think the experiment was successful, given its limitations. Which I would change given the opportunity to reattempt the experiment. **www.can.uni.edu I Temp in 0C 15 20 25 30 35 Daphnia 1 4.58 1.73 6.25 6 3.51 Daphnia 2 6 6.93 7.94 4.58 4.86 Daphnia 3 9.17 6.93 7.55 30 1.53 If standard deviation is small it shows a small spread of data therefore the data is quite accurate. If standard deviation is large it shows a large spread of data therefore the data is inaccurate. Looking at the error bars on the graph shows this. Kieron Harper 1 ...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.

    investigation did have a brood of eggs in their brood pouches; these could be seen under the microscope. There was also a variation in sizes of the daphnia; typical daphnia live for 40 - 56 days, some of the daphnia used could have been at different stages in their life, plus males are typically smaller than females.

  2. Effect of Ethanol on the Daphnia heart rate

    Get someone to count 15 seconds with the stop watch. During 15 seconds, tap the paper with the marker each time the heart beats, after this, count the number of dots on the paper.

  1. Stem Cell Research

    antigens on the outside; therefore the patient's body would not recognise it as foreign. It is not possible to inoculate embryonic stem cells from the patient's own body, because embryonic stem cells can only be acquired from a blastocyst (an embryo in its earliest stages).

  2. The heart rate of a Daphnia (water flea)

    If it is not allowed enough time to acclimatise, I will get inaccurate results because the heart rate (if it changes) will still be the same as it was at the previous temperature. This would lead to a set of results that hardly changed at all.

  1. An investigation into the effect temperature has on the activity of the enzyme catalase ...

    Enzymes have a specific range of pH at which they are most active and therefore productive; above this specific range (generally acidic) the enzyme tends to gain hydrogen ions from the solution. Below this range (normally alkaline) the enzyme tends to lose hydrogen ions to the solution.

  2. The Heart Rate of Daphnia Under Different Conditions

    Do the same for all the other drugs. Results: A table showing averaged class results of different drug solution. Solutions pond water 10%ethanol Caffeine Aspirin Nicotine 1% alcohol Control Trial 1 25 23 30 29 50 19 Trial 2 24 27 29 27 48 22 Trial 3 25 24 31

  1. Should you vaccinate using the HPV vaccine?

    swimming pools or hot tubs Who is most susceptible to contracting Human papillomavirus? Some people will be more susceptible to this virus than others, for example a woman who has remained abstinent or has only had one sexual partner whom was a virgin before he/she met her would have an

  2. Bioligy Data Analysis Task

    the modern bodies of homosapien, causing the runners to do this without any actual threat. This process causes the runners respiratory systems and heart rate to experience a dramatic increase in activity. In this particular experiment their heart rate goes from 85 BPM (beats per minute, on average)

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