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Investigating Pleurococcus

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Investigating Pleurococcus Plan Pleurococcus is a green, single-celled algae that is found on the bark of trees, where it survives better on the north side of the tree and near the ground. It can also be found on stones and fences and usually in moist situations. As it is a green plant, as all green plants do - it photosynthesises. The chemical reaction that is taking place is: Carbon Dioxide + Water Glucose + Oxygen 6CO2 + 6H2O C6H1206 + 6O2 Variables that affect Pleurococcus: > Light: is required for photosynthesis > Moisture/humidity: if it is too dry, the Pleurococcus will become too dry and die out, as they are green plants and require humidity/moisture to survive. > Wind: It can transport moisture. However, it could bring about drying out and death of the algae. > Temperature > Amount of rainfall that runs down the tree. If it is too much, it washes off the Pleurococcus These are called Abiotic Features. Variables that are Biotic are: > Position on the tree: leaves may cause dimness and branches may change the local humidity conditions. > Animals: birds and animals may remove the Pleurococcus. > Tree species: each tree has its own rind category, some more appropriate to the Pleurococcus than others. > Location: the location of the tree will largely influence abiotic factors (e.g. shadowing effects of other trees and disclosure to the elements) ...read more.


We will also make sure that we always measure the Pleurococcus and the Light from exactly one metre high. Also, we will make sure that the same person is measuring one metre, the same person is measuring the light, and the same person is counting the amount of Pleurococcus. We will also make sure that the range of trees we pick will always be the same. We will repeat this experiment on ten trees to make sure that the results we obtain are accurate and make it a fair test. We will also make sure that we use the same type of quadrat each time - 10 x 10 squares (100 squares altogether which will give us a percentage). This is only a sample of how much Pleurococcus there actually is on a tree. Analysis Amount of Algae (%) Amount of light (%) Tree Number North East South West North East South West 1 38 25 96 100 92 91.7 94 94 2 100 30 22 10 88.7 99.5 87 94 3 32 17 94 12 89 86 91 90 4 33 27 24 90 84 82 88 91 5 7 35 0 36 83.8 85.7 89.1 87.6 6 16 63 3 0 84.5 84.8 89.4 88 7 65 85 20 8 84.8 88 90.8 87.1 8 100 64 23 100 79.8 85.2 87.1 85.2 9 50 61 9 44 87 93 93 88 10 15 4 23 0 84 85.7 92 89 Average 45.6 ...read more.


We have no specific reason why, though we made every effort to make sure that our experiment was as fair as possible. We estimated the amount of Pleurococcus that was on the tree with the quadrat, as counting each bit of a square would be too time consuming. However, to make this experiment accurate, we could do that, however time consuming it may be. If we were to repeat this experiment, we would improve it by taking two different heights, and then taking an average. This is because more Pleurococcus could be higher up on the tree. We believe, with the help of the scientific explanation of the rising and setting of the sun (rises in the east, sets in the west, leaving the south exposed to more sunlight), that we can make a reliable conclusion. This is because the evidence that we have gained proves this. Even though 9/10 trees that we measured gave odd results, we can make a reliable conclusion. The reason we got odd results, could have been because the Pleurococcus could have been affected by biotic features such as animals scraping off the Pleurococcus, or the shading and sloping of the tree. To take our enquiry further, we could test the humidity, to check how the water in the atmosphere, could affect the growth of Pleurococcus. We could also test upon different species of trees, as some trees could provide better conditions for the Pleurococcus to grow in. ...read more.

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