The measurements for the lengths of the fronds did show some variation. The figures ranged from 70cm to 154cm. The first measurement was 113cm the tenth was 99cm, the fifteenth 143cm and the final measurement made was 103. These values gave a mean of 109.55, a variation of 604.05, and a standard deviation of 24.58.
The figures obtained from the rocky shore (the exposed shore) gave very much different ranges of values. The number of bladders ranged from two to six and varied from six for the first reading obtained to four for the fifth, three for the tenth, two for the fifteenth and four for the last frond look at. The total figures obtained for the number of bladders gave a mean of 3.75 hence a variation of 2.51 and a standard deviation of 1.59.
The distance between the first and second bladders on the fronds on the exposed shore also varied. They ranged from 5 cm to 21cm. They varied from 11cm for the first measurement to 12cm for the fifth, 5cm for the tenth with 9cm for the fifteenth and again 9cm for the last measurement taken. These figures gave a mean of 9.45cm, a variation of 3.66 and a standard deviation of 13.42.
The total length of the fronds measured varied from 79cm for the first reading, 51cmfor the fifth, 55cm for the tenth, 67cm for the fifteenth and finally 61cm for the last measurement obtained. The values ranged from 30cm to 80cm. These figures gave a mean of 58.40cm, a variation of 233.31 and a standard deviation of 15.27.
The number of bladders on the A.Nodosum was higher than the sheltered shore coastal plants than the rocky shore, simply found by looking at the means of the number of bladders on each shore. The mean number of bladders on the sheltered shore was found to be 4.70 whereas the mean for the exposed shore was lower being 3.75.
The distance between the first and the second bladders on the fronds were significantly higher on the sheltered shore. The mean distance was higher on the sheltered shore, 15.6cm, higher than that of the exposed shore 9.45cm.
The lengths of the fronds also gave higher figures for the sheltered shore, as the mean length there was 109.55cm, higher than the mean length of the fronds on the exposed shore, which was 58.40cm.
There was a correlation with the number of bladders on the frond to the actual length of the frond. The longer the frond the higher the number of bladders on it.
There are more bladders on the fronds of the plants on the sheltered shore. This may be attributed to the fact that the plants on the sheltered coastline do not experience as much wave action as those on the rocky shore. Hence they tend to retain to retain more of their bladders compared to those found on the rocky shore. Also because of the wave action the plants on the exposed shore could be damaged more frequently because of the wave action compared to those found on the sheltered shore where they were experiencing a much lesser intensity of wave action. The rocky shore had less bladders on the A.Nodosum because of them being subject to more of a full intensity and frequency of the wave action hence limiting the life of the plant by loosing its bladders which are an adaptation for its survival. However on the sheltered shore where the influence of the waves on the plants is much reduced so they tend to have many more bladders in terms of their distribution along the length of the fronds. Thus the actions of the waves is the main influence on the distribution and numbers of bladders found on the A.Nodosum. The numbers of bladders the plants have give an indication of its age as only one every year is grown. The bladders are needed for the seaweed to survive as they provide it with buoyancy being filled with air ensures that the plant floats on or near the surface when submerged. This in turn results in a faster rate of photosynthesis and thus a faster rate of growth
Because the variations that were investigated were continuos variations, the t-test was used to test the statistical significance of the continuos variables. The t-test is used when the sample size is relatively low e.g. under thirty (the sample size which was actually used was twenty). The mean and standard deviation of these small samples are prone to error since one single extreme reading will have a disproportionate effect. The t-test will account for this error. The t-test was used in the case of this investigation because the data was related to one another, they were normally distributed, they had similar variances and the sample size was small. When talking about significance it means the significance of the continuos variation and so the t-test is a means of telling us whether the variation is enough to be though irrelevant and. The lower the significance the lower the chance for error there is. From my results I generated t-test values. I did this to show whether my results were just based on chance or whether they were significant enough. For my results my t-test produced the following: No of bladders 1.77, distance between first and second bladders 4.58, the ratio of no. Of bladders to length 4.29 and the t-test for the length of the frond was worked out to be 7.91. A t-test value of 1.77 means a probability of between 5% to 10% is obtained. By using 40 as a degree of freedom 1.77 lies in-between the figures of 1.684 and 2.021. This means that there is a 5% to 10% probability that the results gained where by chance and so the t-test is significant as the probability of chance is too high therefore I cannot reject the null hypothesis. The number of bladders on the sheltered shore compared to that on the exposed shore were due to chance and not as a result of their adaptations to their different habitats.
However the t-test for the distance between the first and the second bladders on the frond proved to be different. A figure of 4.58 was generated, this value has a significance below 0.1% which is 3.551 and so it can be said that the t-test is highly insignificant. This means that we can reject the null hypothesis meaning that the results from the different shores were due to adaptations to their different habitats.
The t-test for the ratio between the number of bladders and the lengths of the fronds was also highly insignificant as it gave a figure lower than 0.1% significance. Remembering that 0.1% is equal to 3.551, the t- test was 4.29. Again tells us that we can reject the null hypothesis meaning the results gained are due to the adaptations of the Ascophyllum Nodosum due the two different environments, the exposed shore with the greater wave intensity and frequency and the sheltered shore which has minor wave intensity and frequency.
The biggest value that came out of the t-test was the test for the length of fronds. This gave a value of 7.91 which is well below the 0.1% significance of 3.551. We can therefore again reject the null hypothesis and again claim that the results are do to the adaptations and as a result of the different environments.
A running mean was calculated. This was to show whether the sample size collected was adequate enough to give accurate results to draw upon a reliable conclusion. The graph showed the mean to level off after around ten results and only varied by a few percent.
The causes of the differences may have been due to allopatrick speciation. This is characterised by spatial separation, geographical barriers such mountain ranges, or habitat preferences, which happens to be the case for the Ascophyllum Nodosum. Adaptation to new conditions or random genetic drifts in small populations leads to changes in allele and genetic frequency.
The ratio of frond length to the number of bladders also provided some insight to the nature of the Ascophyllum Nodosum as the graph of normal distribution could show that the t-test is a significant test. The ratio basically shows the rate at which the plant grows on the shore because only one bladder comes about each year. The ratio was higher on the sheltered shore. This means that the plants were being allowed to grow for longer and therefore faster due to the minor wave action that is much harsher at the exposed shore. This results in it having a lower ratio, as the plant tear easily by the action of the waves and so they cannot grow as well. There was a trend of the number of bladders to the length of the fronds. The longer the fronds were the more bladders tended to be on them. This is because the bladders are an indication of the plants age. The plants, which are longer, have been growing either quicker or for longer; the number of bladders and the ratio that gives us a rate of growth shows this.
There were no real anomalies as the figures varied generally from their maximum values to their minimum values.
There may have been sources of error from the way the investigation was carried out. The method of sampling was random and not systematic. Random sampling was used to discourage bias. There are drawbacks with this method; parts of the shore may have been sampled that experience much more or less wave action than the rest of the shore leading to the overall means being lowered. This error was avoided as if a bare spot was met we simply used another set of random numbers to leads us to our next sampling spot. There could have been more samples done. This would have reduced the number of possible anomalies that could have occurred. This was not the case as the case however as the results didn’t show any real anomalies and the graph for the running means levelled of before the twentieth sample was plotted. The other source of error that could have been encountered could have been due to the fact that we picked the longest frond from one plant from each quadrat. We may not have actually seen and sample the longest frond from each quadrat in which samples were made. This wouldn’t have made much difference as the fronds on all the plants found in the quadrat were roughly the same as they were growing in the same area causing them to have similar lengths, number of bladders and the distances between the first and the second bladders. Being in the same area (the quadrat) the plants would be tolerating the same conditions.