To investigate the relationship between the species richness and distance from a Cedar tree using an interrupted belt transect.
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AS Biology Coursework Aim: To investigate the relationship between the species richness and distance from a Cedar tree using an interrupted belt transect. Hypothesis: As the distance from the tree increases the species richness decreases. Apparatus: Measuring Tape- 10 meters will be needed to measure out the area I will be working in, as I will have intervals of one metre and then every other metre. Quadrat- 0.5cm² ungrided quadrat will be needed; if I use the grided quadrat I would be measuring the types of species present. In order to analyse the frequency of species present in the quadrat I will need an ungrided quadrat. Soil Pin- used to measure the soil depth. Spoon- used to pick out soil samples. Soil Pots- used to store the soil samples in order to take the pH of the soil. pH meter- used to evaluate the pH of certain parts of the soil, and to see whether it is neutral. Also to see if the pH of the soil is a factor which affects my investigation. Beakers- used to mix in soil and distilled water to take note of the pH. Light meter- needed to record the light intensity, and to see if light is a factor, which affects my investigation. 30 cm ruler- used the measure the soil depth when using the soil pin, as centimetres is more accurate than greater measurement units. Pilot Study: I will carry out this investigation, by taking into consideration all the risks and precautions. I will also make sure that I carry out a fair test in order to provide me with accurate and reliable results. I will undertake the ethical implications of the living organisms and the environment. In order to carry out this investigation I will make sure that my apparatus and materials are handled knowledgeably. I will also make sure that my investigation is well organised and carried out in a systematic manner.
I could not afford to make a mistake with the soil sample because I would have to wait for my turn to re-use it. Variables: Independent Variables: the factors that I will change. In this experiment the variables that I will be making changes to, would be the co-ordination of where I will be placing my quadrat in the region of the 10 metres. Dependent Variables: the factors that I will measure during his investigation will be the: Depth of the soil: so I can see if there are more species present where there is more soil or less soil available. Measuring the soil depth with extra care will control this variable as I will not force it into the soil. How many species present in the quadrat: the most important variable will be measuring how many species are present on different co-ordinates of the soil using a quadrat. I will be able to identify the frequency of species present and not the type of species present in the quadrat. Measuring the species present accurately with the correct equipment will control this variable. Soil pH: I will also take note of the soil pH to see whether the soil is neutral and to see if this is a factor, which affects my results. Using the pH meter correctly will again produce reliable results. Light Intensity: I will be using this to see where there is more light available and to find out why there is more or less light available in specific places and to see if this is a factor which affects my investigation. Using the right equipment for this particular experiment will result in controlling this variable. I will do all this research to analyse my results and see whether they match to my predictions. I decided to collect this amount of data, which will make my results more accurate and reliable.
From my summary of results and my graph there is a pattern including with the error bars. I think that overall my method and techniques were correct and I did not write up any poor steps in my method and this did not affect my results. If I had more time for my investigation I would have repeated the experiment at least once more all the way around the tree four times so that I would definitely have more accurate and reliable recordings. So that I could expand on my investigation and have more to write about because I would have more comparisons to be make and more key differences to identify. I would also make sure that my quadrat's distances were equal to one meter apart from each other so that again my results would be more reliable, and that no anomalies would occur unless it had something to do with nature. I would have also made sure that my soil pin was used correctly as I may have pushed it down into the soil with a little extra force or I may have done the whole thing incorrectly. So with the extra time could have repeated the soil pin test again and got the correct measurements. I would also re-do the light intensity and pH meter tests again to obtain trustworthy results because I would have more time to do the tests instead of rushing myself against time to speed up the process. If I were to the whole investigation again I would repeat the whole experiment again but on a different area on the field, and also on a different cedar tree to see if I obtain similar results. I would improve my investigation by not making it very time consuming and doing everything correctly to satisfy myself and to make sure I get precise results I have learnt many new things through this investigation for my own knowledge such as how to use a pH meter, light meter also how my hypothesis was correct.
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