Hire Writer To reproduce Daphnia require a pH of between 6. Daphnia can actually survive outside of this pH, it is only the reproduction that is restricted. Daphnia are quite hardy when it comes to extremes of temperature although the optimum temperature is ?
Investigating factors affecting the heart rate of Daphnia Class practical In the water flea Daphnia, the single, small heart is easily visible when viewed under transmitted light under a low power microscope.
The heart rate which can be up to beats per minute can be monitored and counted in different conditions — for example changing water temperature, or changing the type and concentration of chemicals added to the water.
A change in Daphnia heart rate may not be a predictor of a similar change in human or vertebrate heart rate under the same conditions, but the procedure provides an interesting technique for investigating the effects of different chemicals on a metabolic process.
Thanks to the British Pharmacological Society for providing the teaching notes on this practical.
With modifications made by Prof Richard Handy, University of Plymouth Lesson organisation This will depend on access to a healthy culture of Daphnia and on the number of microscopes you have. Students can readily follow this procedure working in pairs.
Because of the variability of results between individual Daphnia, it is not appropriate to draw conclusions from one set of results; each pair or group of students should carry out more than one investigation to contribute to the class set. One option is to record a live video of a sample Daphnia, during a time period in which students count the heart beats.
Then you replay the video in slow motion and count the heart beats again. This allows students to consider the accuracy of their counting.
If your time or access to chemicals is limited, you could allow the students to work through the procedure in order to evaluate it and then use the example results provided for analysis. Apparatus and Chemicals For each group of students: With pond water culture, or other sources of food, more careful hygiene precautions are necessary.
You will find more details in section L Daphnia are crustaceans, commonly found in ponds and lakes and widely sold as live fish food. These animals are fascinating objects for observation and study in their own right. They feed by filtering minute particles such as bacteria and algae, from the fresh water in which they live.
Daphnia can be kept in any watertight container containing tap water that has been allowed to stand for a few days. Keeping a few Daphnia is not difficult, but cultivating a vigorous, dense colony requires some care.
A good supply of oxygen is necessary, either by aeration or by using a large shallow tank to ensure that a large surface area of water is exposed to the air.
You can purchase live cultures from suppliers, including pet shops and local aquarists. Some scientific suppliers sell viable dried Daphnia eggs and culture kits. Stock purchased from aquarists is usually free from this hazard.
The safest, most hygienic and most convenient ways to provide the necessary food for a colony of Daphnia is to feed them on a few drops of a suspension of fresh yeast or of egg-yolk medium made by blending a hard-boiled egg in cm3 of water. Alternatively, you can buy food such as Liquifry No 1 or Spirulina powder from aquarists or scientific suppliers.
Small, regular supplies of food are required. Provide only sufficient to cause the water to turn faintly cloudy. After a few days the Daphnia will have filtered out the suspended particles of food, making the water clear once more, which is your cue to add more food.
Clear scum from the surface of the water; but leave debris that sinks to the bottom — it may contain Daphnia eggs. An additional, larger dish outside the small one could also be filled with water at the appropriate temperature to help reduce heat loss from the experimental chamber.
Refer to Hazcard 3C Each compound will have different hazards and associated risk control measures. Acetylcholine is an irritant to eyes, respiratory system and skin and is used at a concentration of 1 g in cm3 of water.
L-adrenaline epinephrine is toxic by inhalation, in contact with the skin and if swallowed.The Effects of Alcohol and Caffeine on Daphnia By Brooke Scribner, Courtney Stoddard, and Erin Garrison What is Daphnia magna What are stimulants?
Alcohol will slow the regular heart rate Predicted Results Effect of Caffeine on Heart Rate Effect of Alcohol on Heart Rate Caffeine will increase the heart rate past the normal count of beats.
Just like you, a daphnia’s heart will beat faster when it receives a dose of caffeine. Caffeine belongs to a class of compounds called methylxanthines and can block a receptor on the surface of heart muscle cells for adenosine.
How much does caffeine really affect your heart rate?
|One thought on “Effect of Caffeine on Daphnia Heart Rate”||Investigating factors affecting the heart rate of Daphnia Class practical In the water flea Daphnia, the single, small heart is easily visible when viewed under transmitted light under a low power microscope.|
It may not be as much as you think. Home Communities Create Shop. How Much Does Caffeine Really Affect Your Heart Rate? The results are random at best and a clear answer is not present with how much caffeine actually affects heart rate. To make this better, subjects should all be in the.
Jun 26, · Leave the Daphnia for 5 minutes to acclimatise and then observe & count (using a counter) the heart rate under the microscope for 30 seconds (multiply number by 2 to calculate beats per minute).
Repeat this for measurements across 5 different . Results As can be seen from the graph, the mean heart rate of the Daphnia increases up to % concentration of caffeine (with a mean heart rate of approximately beats per minute), from % to % concentration of caffeine the mean heart rate remains constant at .
hypothesis which stated the average heart rate of D. magna in the caffeine treatment groups (, , and mg) will be significantly lower than the average .