This investigation was designed to compare the height of Pteridium aquilinum in a light area and a dark area of Rushy Plains, Epping Forest and to establish if light intensity does have an effect on the growth of Pteridium aquilinum, commonly known as Bracken. From my research it was clear that the height of Bracken is affected by abiotic factors, other than light intensity, such as: soil moisture, soil temperature, air temperature and soil pH so I had to control these factors. I carried out preliminary experiments to find a suitable site where all these factors where constant. For my actual investigation I measure twelve random Brackens from both light and dark areas. I then carried out a Mann Whitney U test and concluded, with 95% significance level, that there is in fact a difference between height of Brackens from a light area and a dark area. Hypothesis
Alternative hypothesis (H1): There is a significant difference in height of Brackens from a light area and the height of Brackens from a dark area. Null hypothesis (H0): There is no significant difference in height of Brackens from a light area and the height of Brackens from a dark area. Prediction: The height of Brackens from a light area will be greater than the height of Brackens from a dark area. Aim
During my investigation, I aimed to look at whether there is a difference in height of Brackens from a light area and a dark area due to light intensity. In order to carry out my investigation I needed to research into the different factors that affect the growth of the plant. I also planned and carried out preliminary investigations to make sure all the control variables are constant before I did the main investigation. I recorded my findings and did a statistical test on my data to see whether the data show a significant result.
Research and Rationale
Bracken (Pteridium aquilinum) is a native British fern commonly found in woodland and heathland. It is tolerant of a wide range of soils and climates. Bracken is typically fern-like, producing triangular fronds, divided into three, that can reach up to 2m in height. In autumn the fronds turn reddish-brown and die back to ground level, with new fronds unfurling from the base in spring. (Jan Toman and Kvetoslav Hisek, 1998) Picture 1
Investigations such as this widen our knowledge of how living things interact with non living factors, and this knowledge becoming increasingly important as ecologists are trying to find new methods of cultivating plants in conditions that might not be particularly favourable and also new methods of controlling the growth of plants. I chose to carry out my investigation on this particular plant as it is known to have a toxin called Ptaquiloside, which is highly carcinogenic. Knowing more about what affects the growth of the plant can help limit the growth of it therefore avert any harm to any animals or even humans.  Research:
There are many factors that affect the growth of a plant with light intensity being one of the major ones. Other factors include: Air temperature, Soil temperature, Soil moisture and Soil pH  How does light intensity affect the plant?
Light is an absolute requirement for plant growth and development, without light there is no energy to drive essential reactions. There are three processes in a plant that requires light: Photosynthesis, Photoperiodism and Phototropism. All of these processes affect the growth ergo the height of the plant. Photosynthesis:
Photosynthesis is the process by which plants convert carbon dioxide and water into simple carbohydrates and oxygen in the presence of chlorophyll using sunlight. Photosynthesis is a process that is gravely important to not only plants but animals too, as it starts off the food chain; animals which are unable to make their own food (hetrotrophs) feed on plants...