Biotic factors will also have to be taken into consideration; these
To what extents do abiotic factors affect the rate of photosynthesis?? Biotic factors will also have to be taken into consideration; theseinclude things like food, plants, animals, and their interactionsamong one another and the biotic environment. One factor that may needto be taken into consideration could be how vulnerable the ivy leavesare to human or animal interference, for example trampling. Humanactivities produce a wide variety of pollutants of land, air andwater. The closeness and intensity of any human activities will beconsidered as well. All these biotic factors will need to taken intoaccount while carrying out the experiment in both the regions in thewoodlands. Biotic environment includes such factors as soil, water, atmosphere,and radiation. The biotic environment is made up of many objects andforces that influence one another and influence the surroundingcommunity of living things. Other biotic factors include the amount ofliving space and certain nutrients (nourishing substances) availableto an organism. All organisms need a certain amount of space in whichto live and carry on community relationships. They also must havenonliving nutrients, such as phosphorus, to maintain such bodyactivities as circulation and digestion. Ecology is the study of therelationships between organisms and their environment. · Light intensity – As light is the ultimate source of energy for allecosystems. This is the variable that is being investigated in myexperiment. I will be expecting to
see a significant difference in thesurface area of a leaf in a shaded (low light intensity) and in anunshaded region (high light intensity). Where in the shaded region thesurface area of the ivy leaves will tend to be greater than those thatgrow in an unshaded region.· Air humidity – An increase in humidity causes a direct increase intranspiration, this is due to the rate of water movement from insideof the leaf to the outside surrounding area of the leaf. The greaterthe difference in humidity the faster water moves. Water vapours movefrom an area of high relative humidity to an area ...
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see a significant difference in thesurface area of a leaf in a shaded (low light intensity) and in anunshaded region (high light intensity). Where in the shaded region thesurface area of the ivy leaves will tend to be greater than those thatgrow in an unshaded region.· Air humidity – An increase in humidity causes a direct increase intranspiration, this is due to the rate of water movement from insideof the leaf to the outside surrounding area of the leaf. The greaterthe difference in humidity the faster water moves. Water vapours movefrom an area of high relative humidity to an area of low relativehumidity.· Wind Speed – This factor is linked to humidity, and will also oftenresults in an increase in transpiration as well. This is due to thefact that once the water vapour has diffuses out of the leaf into thesurrounding air, if wind is present, it will move away these humiditybubbles. As a result this will cause a new desirable diffusiongradient for more water vapour to rush out when the stomata opens,causing a transpiration to occur at a faster rate.· pH of soil – This is another important factor as it is affected bythe availability and absorption of several elements needed for plantgrowth. Maximum absorption of these elements is found at pH readings5.5 to 6.5. The pH of a soil influences its physical properties andthe availability of certain minerals to plants. If the pH of the soilfalls below the given range it results in less availability of theelements N, P, K, and the absorption of the micronutrients can reachtoxic levels. Moreover enzymes have an optimum pH at which they workat, if the soil is too acidic or to alkaline, this will denature theenzymes, which will affect the rate of photosynthesis and affect thesize of the leaf.· NPK-nutrient concentration of soilØ Nitrogen – this element is a constituent of amino acids, proteins,coenzymes, nucleic acids and chlorophyll. Nitrogen has a great effecton plant growth. If missing, then plant will be underdeveloped and oldleaves would turn yellow.Ø Phosphate – the element is involved in photosynthesis, and needed inthe light independent stage to be more precise. If this element is notavailable the young leaves will turn purple and roots will struggle togrow.Ø Potassium – this element is needed by enzymes which are involved inphotosynthesis and respiration. A shortage of potassium would resultin leaves turning yellow and developing dead spots.· Temperature of air and soil – All chemical and biological activitiesof a soil are influenced by temperature. The temperature of a soil maybe from that of the air above it. Evaporation of water from soil maycool it to below that of the air, whereas solar radiation may raise itabove air temperature. Soil temperature affects plant growthindirectly by affecting water and nutrient uptake as well as rootgrowth.Reliability, Measurements and AccuracyIn this investigation, 60 ivy leaves from a shaded region and another60 leaves from an unshaded region from the same woodland will bemeasured. The abiotic factors in both areas will be measured too.Two 10m tape measures will be placed at right angles to each other.The square quadrat will then be placed using random co-ordinates. Thismethod seems to be the most efficient and reliable way to locate andmeasure ivy leaves randomly, in each region. The square quadrat is abetter option than the point quadrat because due to the lack of timethe square quadrat is a quicker and more appropriate way to collect mysample of ivy leaves. Moreover, the ivy leaves that are going to beused in the sample will all be from within the square quadrat, so theyare all likely to be in the same environmental condition as eachother; this adds a sense of fair testing to my experiment. Enzyme activity is also influenced by pH, if the pH is too acidic oralkaline, then the enzyme is likely to denature, resulting in it notbeing able to bind with its specific substrate molecule. The pH in theshaded region was slightly acidic compared to the unshaded habitat.The pH in the shaded region was 6.5 and in the unshaded region it was7.5. However, the ivy plants are known to be capable of living inadverse soil conditions I thought that the method of collecting my data was quite reliable andappropriate for this experiment. However for future experiments Ishould look to collect a much larger sample size. Due to timerestraints, I was able to collect 60 leaves from each region; this istoo small a sample size to base a conclusion on. Nevertheless we areable to see a clear observation that the size of the ivy leaves tendsto be smaller in unshaded areas, and larger in shaded areas. Moreovera greater section of each area may have been taken into consideration,to help make the results more reflective and reliable. The ivy leavesthemselves were measured to mm2, which I believe was fairly accurate,yet mistakes may have been made when trying to trace around the ivyleaves. This is another method which would need to be improved on forfuture experiments, to help give a more accurate result.As light intensity was the main abiotic factor being investigated,three light intensities were measured in each area at differentdistances from the ground (50cm, 100cm and 150cm above ground level).This way the best possible value for light intensity in the areaoverall can be measured. When light intensity was measured using thelight probe, the probe was directed towards a clipboard from eachheight. This was to ensure a consistent, reliable and reflection isdetected by the light meter. Whilst light intensity is the onlyabiotic factor which was being investigated, it would have been idealif all other abiotic factors remained the same in both areas,throughout the experiment. However this was not the case as we cannotcontrol them, but any differences were be taken into account. Tominimise the effect of each variable, the investigation took place onthe same day, to ensure a certain degree of fair testing. There were no anomalous results, but if there had been any anomalousresults they would have been most likely due to human error more thananything else. All precautions were taken while carrying out thisexperiment. Safety Goggles and gloves were worn when carrying out thepH and NPK test, the equipment was used in an orderly and responsiblemanner and any spillage was cleaned up quickly and disposed of.
