Rana Srouji's Fast Plant Mini Lab

Rana Srouji

The Effects of Artificial Selection on Wisconsin Fast Plants

Analysis:

Figure #1:

In order to observe directional selection, we tested a group of Wisconsin fast plants to see if selection for the average leaf length would influence the later generation phenotypes.  The null hypothesis for this lab is that there would be no significant difference between the means of the parent generation, and the offspring (F1) generation.  

We began the experiment by growing the plants, and after 9 days we took the measurements of the leaf lengths on each plant, and calculated the average leaf length per plant.  This population of fast plants is the parent population which consisted of a sample size of 57 plants.  The graph of the data collected for this population is represented in a histogram which specifically shows the distribution of the average leaf lengths (Figure 1).  The histogram does not show a bell curve because the data is not perfect.  On average, the mean for the leaf length is about 8.84 mm and the median is 8.5 mm.  Most of the plants fall around the 4 mm to 10 mm average leaf length range, while there are a couple of outliers because some plants had really long leaves.  The leaf lengths ranged from about 4 mm to about 20 mm.  The calculated standard deviation is about 3.39 and the SEM is about 0.45. The lower limit of the 95% confidence intervals for the data is rounded to 7.94 while the upper limit of the 95% confidence intervals for the data is rounded to 9.74.  

Figure 1

Figure #2: 

Afterwords, to apply a selection pressure on the population, we selected for plants who had an average leaf length of 12 mm or greater.  Those plants who had shorter leaves were cut off and could not reproduce.  Only 8 of the plants survived the selection and we collected the data for these plants, which is also represented in a histogram, that shows the average leaf length for the survivor plants (Figure 2).  Similar to the previous graph, it is not a bell curve.  The data ranged from average leaf lengths of 12 mm to about 16.5 mm.  This difference in the leaf lengths would cause the mean of the leaf lengths to be higher than in the parent generation.  On average, the mean leaf length for the survivor plant generation is 13.88 mm and the median is 13.75 mm.  Most of the plants had an average leaf length from 12 mm to 12.75 mm and from 13.5 mm to 14.25 mm.  The calculated standard deviation is 1.26 and the SEM is 0.45.  The SEM stayed relatively the same throughout both populations.  The lower limit of the 95% confidence intervals for this generation is 12.98 while the upper limit is 14.78.

Figure 2

Figure #3:
Lastly, after the survivors had fully grown, we took out the seeds from inside each of their pods, and planted them for the offspring generation.  Once the offspring, otherwise known as the F1 plants, grew, we collected data which is shown in a histogram of their average leaf lengths (Figure 3).  This final graph does show a bell curve of the data with the curve shifted a bit towards the left, and the least frequent average leaf lengths lie on the ends.  The total amount of plants in this generation is 33 and their data ranges from average leaf lengths of about 3 mm to about 12 mm.  Most of the plants had an average leaf length that lied in the range from 6 mm to 7.5 mm.  The mean leaf length is about 6.46 mm and the median is about 6.33 mm.  The standard deviation is about 1.81 and the SEM is about 0.31.  Similar to the survivor generation, the standard deviation is much lower than the parent generation.  The lower limit of the 95% confidence intervals is about 5.83 and the upper limit is about 7.09.  These confidence intervals do not overlap with the confidence intervals of the parent generation before the selection.  

Figure 3

Table #1:
The collected data was calculated and configured in this data table (Table 1).  It shows the sample size, mean, median, standard deviation, SEM, and confidence intervals for all three generations of fast plants.  

Table 1

Discussion:

Conclusions:

Natural selection is the process in which organisms that are better adapted to their environment survive and produce more offspring in comparison to those who are not.  One form of natural selection is directional selection, which favors one extreme phenotype, in a population of organisms, over the mean and other extreme, causing the allele frequencies of the later generations to shift in the direction of that phenotype.  This is usually best seen in graphs of the population over time, since directional selection will cause the original bell curve to shift either farther to the left or right.  Also, it is helpful to look at the standard deviation of a population because it tells how far the measurements are spread out from the average/mean, and the lower the standard deviation is, the closer most numbers are to the average, while higher standard deviation means that numbers are spread out.   

For this we grew plants and in the parent population, we cut off plants with leaf lengths that are less than 12 mm in length.  Using the data and graphs from the parent population, the survivor population, and the offspring population, we were able to reject the null hypothesis which stated that there is no significant difference between the means of the parent generation and the offspring (F1) generation.  Since the confidence intervals of the two generations do not overlap, this means that there is a significant difference between the means.  We used the parent and offspring generations to compare confidence intervals, which show the mean leaf length for each generation +/- two times the standard error of the mean.  Ultimately, selection for the average leaf length does not influence the offspring generations in this population because as seen in the above data, the mean leaf length in the survivors are not similar to the means of the offspring.  

Though we received a result, there were some limitations in our experiment that could have altered our outcome.  For example, many of the seeds that were originally planted either did not grow or died before the selection process began.  Those that died could have contributed to the amount survivor plants.  

Experimental Evaluation:

The lab was not carried out to the best of our abilities, and this could have also altered the outcome of the experiment.  There were errors that could have been prevented, but got into the way and we had to work around them.  Such as, time management with the fast plants.  Either we were not able to go visit the plants in order to check their progress, or we ran out of time to do so.  The time set for the parent population to grow before the selection, was extended due to the planning.  This could have altered the length of the leaves since they were given more time to continue growth.  To have prevented this, we could have been more organized with our time.  Human error may have also acted as a large factor in the results that we came with at the end of the lab.  The leaf lengths that we determined for our measurements could have easily been misread considering each of us were measuring with large rulers compared to the small size of the leaves.  This would have affected our data collection which is used to reject or fail to reject the null hypothesis.  Using smaller tools to measure length may have prevented this.  

Even though the experiment results may have had multiple errors along the way, I still have some confidence in them.  Many labs and experiments have small errors that could not be seen ahead of time.  The only way to check if the results were accurate is to either have other groups try to do the same procedure and carry out the experiment to see if their results match up with ours; or to repeat the procedure ourselves.

Chigozie's Wisconsin Fast Plant Mini Lab Report

Name:  Chigozie Amonu

The Effect of Artificial Selection on the Average Leaf Length of Wisconsin Fast Plants

Results:

The question that we attempted to answer in this lab was, “Does selection for average leaf length influence F1 phenotypes?” The null hypothesis for this lab was, “There is no significant difference between the mean of the P Generation (Pre-Selection) and the mean of the F1 Generation”. We gathered data in order to answer this question and reject, or fail to reject, this null hypothesis.

Calculations & Statistical Analysis:

Figure 1:  

We planted the P generation on Day 1 of this experiment, and on Day 9 we took measurements of the leaves of all 57 plants and averaged the leaf length of each plant. The histogram below (Figure 1) shows the distribution of the average leaf length in the P Generation of the plants. The mean of the average leaf lengths was 8.84 mm, and the median was 8.5 mm. These values were similar, so we could assume that the data was normally distributed. The calculated SEM was 0.45. The lower limit of the 95% Confidence Interval was 7.94 mm, and the upper limit of the 95% Confidence Interval was 9.74 mm. There was not a definite bell curve to the data that we collected, as seen in the histogram. We later used this data to conclude what we would manipulate during our artificial selection.

Figure 2:

After we gathered the data from the pre-selection P Generation, the class collaboratively decided to select for leaf lengths of 12 mm or greater. The leaves that did not meet this criteria were cut off. After this selection, 8 plants remained. This histogram (Figure 2) displays the data that we collected from the survivors of our artificial selection. We selected for leaf lengths of 12 mm or higher. Only 8 plants were left after this selection. The mean of these average leaf lengths was 13.88 mm, and the median was 13.75 mm. These values were similar, so we could assume that the data was normally distributed. The calculated SEM was 0.45 mm. The lower limit of the 95% Confidence Interval was 12.98 mm, and the upper limit of the 95% Confidence Interval was 14.78 mm. This histogram also does not display a bell curve with the data that we collected. After collecting this data, we expected the F1 Generation to have phenotypes similar to this post-selection P Generation since we purposely selected for a certain range of leaf lengths.

Figure 3:

After the post-selection P Generation fully grew and created seed pods, we planted the seeds from this group of plants. We then collected data from the offspring. This graph shows the average leaf length of the F1 plants. There were 33 plants in the generation. The mean of the average leaf lengths of the F1 plants was 6.46 mm, and the median was 6.33 mm. These values were similar, so we could assume that the data was normally distributed. The calculated SEM was 0.31 mm. The lower limit of the 95% Confidence Interval was 5.83 mm, and the upper limit of the 95% Confidence Interval was 7.09 mm. This graph is also in more of a bell curve, and the curve is shifted slightly to the left.

Table 1:

This data table shows the descriptive data that was collected during this experiment from the pre-selection P Generation, the post-selection P Generation, and the F1 Generation. Shown below is the sample size, mean, median, standard deviation, SEM, and the lower and upper limits of the 95% Confidence Interval.

DESCRIPTIVE STATISTICS - AVG. LEAF LENGTH OF WISCONSIN FAST PLANTS (mm)
	P Generation	P Generation - Survivors	F1 Generation
Sample Size (n)	57	8	33
Mean	8.839181287	13.88	6.462121212
Median	8.5	13.75	6.333333333
Standard deviation	3.39196426	1.26	1.80735
SEM	0.4492766416	0.45	0.3146201419
95% CI Lower Limit	7.940628004	12.98	5.832880928

Discussion:

Conclusions:

In this lab, we attempted to perform directional selection. This selection would easily be seen in the histograms as the curves in the histograms would shift to the left or right. However, the 95% confidence intervals of the pre-selection P Generation do not overlap with the 95% confidence intervals of the F1 Generation. This allowed us to reject our null hypothesis, “There is no significant difference between the mean of the P Generation (Pre-Selection) and the mean of the F1 Generation”. There is a significant difference between the mean of the pre-selection P Generation and the F1 Generation. Overall, the artificial selection for average leaf length did not affect the F1 Generation.

Experimental Evaluation:

This experiment was carried out with a few errors that could have affected our data that we collected, and as a result our entire conclusion. There were different individuals measuring the leaves of the plants, so the different strategies of measuring could have created incorrect measurements. Also, some measurements and calculations were rushed due to lack of time, so errors could have been made in that aspect. One other error could have occurred from the lack of recording in some areas. For example, the number of survivors from the P Generation was only recorded by one individual, so if that record was wrong, then the whole lab is possibly thrown off. In spite of the possible errors, I am overall satisfied with the conclusion that we received from the lab.

Jube's Fast Plant Mini Lab

Fast Plant Lab Report

The purpose of this lab was to see how selective pressures may affect average leaf lengths. The proposed null hypothesis was that there will be no significant difference between the average leaf lengths of the parent population and the average leaf lengths of F1 generation. We tested this by selecting against shorter leaf lengths. (The data collected can be seen in Table 4).

 

The parent generation had a sample size of fifty-seven plants. The average height of the leaves was 8.84 mm. Furthermore, the median was 8.5 mm. Some plants had leaves less than 8.5mm and greater than 8.5 mm, but they were all within range of 8.84mm. Standard deviation is a measure of variation. The parent generation had a standard deviation of 3.39. This was due to the fact that there were differences in leaf lengths within the population. As shown in the histogram in figure 1, the leaves that were between 4 and 10 mm had the greatest frequencies.  After 10mm, we see a decrease in frequency. These leaves represent the outliers. Furthermore, the standard error for the parent population was .45 which could've also accounted for the inconsistency of the data in the histogram. In addition, confidence intervals were calculated to see how're reliable the estimate of the mean is. The confidence interval for the parent population had an upper limit of 9.7 and a lower limit of 7.9.

                                 Figure 1

The survivors of the parent generation had a sample size of eight plants. There was selection to ensure that all survivors had leaf lengths of 12 mm or longer. The average length of the leaves was 13.88 mm. The mean was 13.75 mm. Therefore, some plants had leaves less that 13.75 mm and some plants had leaves that were greater than 13.75 mm. However, they all fell within the range 13.75 mm. In essence, there was a significant difference in the average leaf length the compared to the parent population. On average, the plants of the survivor generation had leaf lengths about 5.04 mm greater than than that of the parent population. To add, the survivors had a standard deviation of 1.26. As a result, there was a bell shaped curve in the graph due to the differences in the frequency of the average leaf lengths. The standard error of the survivor population was .45. Confidence intervals also allowed for further evaluation of the acquired data. Essentially, the survivor generation had a 95% confidence interval of 12.98 for the lower limit and 14.78 for the upper limit. These intervals don't overlap with the confidence intervals calculated in the parent population. Therefore, we can be at least 95% sure that there is a statistical difference between the average leaf lengths of both generations. When compared to the parent generation, the results vary greatly. The survivor generation has lower frequency rates than that of the parent population, and it is apparent that the shape of the survivor population data is not as skewed.

                             

 Figure 2

The offspring of the survivors (F1 generation) had a sample size of thirty- three plants. The average leaf height was 6.46 mm. The mean height was 6.33. Thus, some plants had leaves with lengths less that 6.33 mm while other plants had a height greater than 6.33 mm. The F1 generation had a standard deviation of 1.81. The heights were not evenly distributed. To add, the standard error was .31. Since the standard error of the mean is such a minute number, most of the calculated leaf lengths were about about average although there were a few outliers. The outliers were the leaves with lengths from 3-4.5 mm and 9-12 mm. However, most of the leaf lengths which ranged from 4.5-9 mm were centered around the average leaf length of 6.46 mm. Essentially, the leaf lengths of the F1 generation are very different from the initial leaf lengths of the parent generation. The F1 generation had a 95% confidence interval of 5.83 for the lower limit and 7.09 for the upper limit. Since these confidence intervals don't overlap with the confidence intervals of the survival population, we can conclude that there is indeed a statistical difference between the average leaf lengths of the survival and F1 generation. Hence, there’s a statistical difference between the average lengths of the parent population and F1 generation.

                               Figure 3

                   Table 4

Conclusion

The proposed hypothesis can be rejected because there was a statistical difference between the average leaf lengths. As recorded in table 4, there’s a significant difference between the average leaf length in the parent generation when compared to the F1 generation. To add, the standard deviations also helped to reject the null hypothesis because they showed varied measures of differences within each population. Each successive generation after the parent population had specific traits, and ultimately it became evident that the parent population greatly differed from the F1 population.  These results were unexpected because I figured that the plants would just grow to their typical length no matter what the circumstances were due to their genome sequence. However, that was not the case in this experiment.

Some limitations to this experiment includes the fact that the class did not check on the plants very often. Hence, they may not have gotten enough water. As a result, they would not have been able to flourish to their maximum capability. In the real world, plants grow to be a wide assortment of various shapes and sizes. Leaf lengths vary greatly in the real world. We can conclude that leaf lengths occur at random as they are affected by environmental pressures and conditions.

Experimental Evaluation:

The confidence intervals calculated do not overlap at any point. My calculations of the 95% confidence intervals upper and lower limits made me 95% sure that there’s a statistical difference between the average leaf lengths of the parent generation and F1 generation. I feel that my group could have used less seeds because many of them died off during the experiment. Therefore, it may have been more efficient to give the seeds more room to grow from the beginning. Also, I feel that if the class had kept a closer eye on the fast plants, we would have been able to make more observations. Furthermore, the room that the plants were placed in may have had an effect on their growth. If we could have regulated the temperature of the room throughout the experiment, there would be more accurate results because each generation would have lived under the same exact conditions. Nevertheless, I still feel confident in the results obtained from this experiment.  

Rameia's Fast Plant Mini-Lab Report

Rameia Ramsey

Analysis

In this Fast Plant lab we planted and grew Wisconsin Fast Plants. By growing these  plants we were able to see what kind of data we would be working with and then manipulate the experiment to produce results that we wanted and would expect. In order to successfully do this we first planted a parent generation which would serve as the foundation for out other generations.  We continued to grow,water, and monitor the plants over a 35 day period in a classroom with the plants sitting on a watering system under fluorescent lighting.  After the growth of our first set of plants, there were a variety of leaf lengths. On day 9 we counted the amount of leaves grown and recorded the leaf lengths of the plants. Our sample size was 57 plants and the leaf lengths of the parent generation ranged from 2mm to 25mm with the average leaf length being about 9mm.  Through the process of artificial selection we decided to  keep plants with a leaf length of 12mm and over.  All of the other plants that did not meet this requirement were cut out and removed. After removing the plants that did not meet the requirements our sample size decreased to just 8 plants.  This meant we had killed off about 85% of the original parent generation.  With the surviving plants we did various calculations to determine the mean, standard deviation, standard error mean, and 95% confidence intervals of the plants.  From there we used bees to pollinate the surviving plants in order to create seed pods to use for the F1 generation. After we planted the newly formed seed pods we then planted them to create the F1 generation.  After this generation grew, we had observed the plants and decided on a question to test.

After the growth of the parent generation, we reached a sample size of 57 plants.  The plants varied in length but there was definitely a higher number of plants who had an average leaf length of about 9mm which is relates to the the mean of the all 57 plants being 8.83mm.  The median of the leaf lengths was 8.5mm so we can assume that our calculations are accurate.  We tested the standard error of the mean which tests the limits of the mean, meaning it accounts for other factors that could influence the mean of the plants.  The SEM of this generation was 0.45mm.  We also calculated the 95% confidence interval which helps to be 95% confident that the mean of our data only varies from other data by chance.  The upper 95% interval  was 9.74mm and the lower limit was 7.94mm.  In the graph shown you can see that there is a bell curve to the data collected.  Based on the data for this generation we used it as a foundation to figure out what we going to manipulate.  We found that there were very little amount of plants with leaf lengths of 12mm and above so we decided to keep those plants and pollinate them for future generations to be made.

After we had killed of 85% of the parent generation so that we only had plants with leave lengths of 12mm or more remaining, there were only 8 plants that remained.  Out of this group of plants there was not much of a variety of the leaf length.  The average leaf length for this group was 13.88mm, with the median being 13. 75mm again showing the accuracy of the data.  The SEM of this group of plants was exactly .45mm.  The 95% confidence interval for the upper limit was 14.78mm and the lower limit was 12.98mm.  There is definitely a significant difference between the survivors and the original parent generation.  Considering we have selected for taller plants we expect that the generation we breed for will be similar to this group and not the original parent generation.  The graph here also shows how there isnt a bell curve to the data either.  This data we collected was then used as a comparison for the F1 generation plants.       After pollinating the survivors of the parent generation, we came to have and F1 generation sample size of 32 plants. In this generation, there was more variety of the leaf lengths similar to like there was in the parent generation with the  the average leaf length being  6.46mm, this number being significantly lower than both the parent generation and the survivor generation.  The 95% confidence interval upper was 7.09mm and the lower limit was 5.83mm, again lower than the parent and surviving generation.  Throughout the generations none of the confidence intervals overlap which shows how our null hypothesis is rejected because there is a significant difference between all of the means of average leaf length for each generation. Our null hypothesis of this experiment was that there is no significant difference between the average leaf lengths of the parent generation and the F1 generation.  As a result of the experiment we reject the null hypothesis.   

Discussion

Conclusion:

This experiment modeled the effects of artificial selection on the Wisconsin fast plants.  This experiment proved that what is expected to happen does not occur as we were expecting to see that parent generation and F1 generation were to be similar.  There means as seen in the first and last figure are significantly different.  Also the confidence intervals do not overlap which means that there is a significant difference between the two generations.  This proves that we reject our null hypothesis. The graphs for the parent generation and F1 generation are also different.  The F 1 generation has shifted to the left which is the opposite of the extreme that we had selected for. With all of this information to look back upon I can make an assumption that the length of the leaves may not be a trait that is passed down even when you only experiment with one extreme of the leaf lengths.  Some of the limitations of the experiment could have affected our data could be the amount of seeds that actually grew into plants.  There were most likely some seeds that did not grow or plants that did not develop enough in order for us to count them as part of the population.  If there were more plants they could have potentially been apart of the survivor generation and help to contribute and pollinate for the F1 generation.  

Experimental Evaluation:

With the results from our experiment for the most part I feel confident that our numbers are correct.  But there are some factors and situations that could have contributed to slight errors in our numbers that could give us potentially a less than accurate result.  I feel as though most of the error that could have occurred was human error not an error of any instruments used. There could have been errors in the parent generation when measuring the leaf lengths of the 57 plants.  There was not one person designated to measuring, we were all measuring and counting different plants.  There is a very good chance that there could have been a misreading of the measurements and not accurate counting of the amount of plants.  We most likely don’t all have the same reasoning when we try to figure out the measurement of an object or deciding on whether or not to count a specific plant as developed or not. This in turn would have affected how many plants we had in the survivor generation and thus affect our results in the F1 generation.  Also, when we left our plants to grow in the classroom under the flourescent lights and on top of the water system we were not always checking up on them as we were supposed to.  So this could have also affected the growth of the plants and further affect the results we received. The light received by each of the plants could have also affected our results.  We never kept up with measuring how far away each of the plants were from the light, so not all of the plants were receiving equal amounts of light based on their positions which could have affected the growth of the plants.  

Joshua Everett's Mini Wisconsin Fast Plant Lab Report

Everett Wisconsin Fast Plant Lab Report

The Effect of Artificial Selection on Wisconsin Fast Plants

The purpose for performing this lab is to model artificial selection within Wisconsin Fast Plants. As a class, we chose the characteristic of average leaf length of the plants to be selected for in which a change in the average leaf length would be predicted in the offspring from the parent generation. The research question we are trying to answer is: does the selection for the average leaf length influence the phenotypes of the offspring? The results of the experiment showed that the research question is not supported by the data that my classmates and I collected.

In the beginning of the experiment, a parent generation of fifty seven Fast Plants was grown within planting units each having four pods. In each pod a diamond wick, planting soil, fertilizer seeds, and fast plant seeds were placed respectively in this order. They were grown continuously for approximately 40 days before the offspring plants were grown. All plants, however, were place on top of a water reservoir to ensure the plants maintained ideal water levels. All plants were also under cool-white fluorescent lights to allow plants to perform metabolic process and grow. After approximately five days the average leaf lengths for each of the plants were recorded (Figure 1). The averages for the leaf lengths vary continuously from plant to plant. (Figure 1). There is no relationship shown between the average leaf length for each plant in which there is no bell curve. The average leaf lengths for the plants are heavily concentrated between four to six millimeters and between eight and ten millimeters. The outliers for this graph are the average leaf length between six and eight millimeters and from ten to twenty millimeters. (Figure 1). The most concentrated averages and the outliers are not integrated in the graph to where a pattern is shown. The data is not normally distributed because if it was, a bell curve would be shown in which the sloping sides would contain the outliers and the curve would contain the average leaf lengths that  are most concentrated by the plants. Another account for why the data is skewed is because the standard deviation is 3.39 which is higher than the standard deviation for the survivors (1.26) and F1 generation (1.81). There is more variation of the data here which explains why the data is not more evenly dispersed. Even though a pattern is not depicted, the curve of the bell curve represents the mean of all the average leaf lengths for the parent generation plants which is 8.839181287.  

Figure 1

From the information from figure one, it was decided by my classmates and I that the leaf lengths under 12 mm was to be selected against. To implement this selection pressure, the class trimmed the leaves of all the plants that had a leaf length of twelve millimeters and below. The outcome the my classmates and I were expecting to see in the survivor parent population were all plants with leaf lengths of  twelve millimeters and over. The average leaf lengths for each plant for the survivors after selection were recorded (Figure 2). There is a significant decrease in the population of the parent population to the survivor population in which the parent population has 57 plants and the survivor population only has 8 plants. The frequency of higher average leaf length is significantly lower than in the original parent population when compared to the survivor population. To make this conclusion, the means of the parent population and the survivor population was compared. The parent population mean is 8.84 and the survivor population mean is 13.88. The average leaf length increased after the selection pressure was implemented. Because all leaf length under twelve millimeters were selected again, only leaf lengths above twelve millimeters were left. This caused a shift in the graph from eight to ten millimeters in the parent population to 13.5 millimeters to 14.5 millimeters. In addition, the dispersion and variation of the data for the survivor population is smaller than that of the parent population. This is accounted from through the standard deviations of the two populations. The standard deviation for the parent population is 3.39 but the survivor population has a standard deviation of 1.26. The smaller the standard deviation, the less variation and dispersion of the data. The standard deviation also accounts for the lack of fluctuation in the graphs because of the lack of variation and dispersion which is why the graph lacks a bell curve. On another note, the SEM of the survivor population is 0.45 and the 95% confidence interval for the survivor population is from 12.98 to 14.78. For the parent population, however, the SEM is 0.45 and the 955 confidence interval is from 7.94 to 9.74. The confidence intervals show the range of the where the means will lie if the experiment is performed again. Since the confidence intervals from the survivors population and the parent population do not overlap, I can conclude that the means for both populations are significantly different from each other. This would imply that the selection pressure that was implemented was a success.

Figure 2

Using the survivors population, my classmates and I performed sexual reproduction with the plants by cross pollinating the plants using bee sticks. If the process is done correctly the plants will produce produced seed pods which  are then used to plant the F1 generation. After letting the offspring grow for approximately nine days, we measured their leaf lengths for each plant a recorded them (figure 3).

The graph now depicts a bell curve in which the data is evenly distributed and an average leaf length can be roughly seen. The mean of the F1 generation is 6.462121212 which is different from the parent population and the survivor population in which their means were 8.84 and 13.88 respectively.  The average leaf length shifted along the graph in which it is not the same as the survivor population but it is similar to the parent population in which the average leaf length now ranges from 6 millimeters to 7.5 millimeters. The means of the parent population and the F1 generation are more similar than that of the survivor population. The standard deviation for the F1 generation is 1.81 which is higher than the survivors standard deviation which is only 1.26. The standard deviation is high for the F1 generation because there were more plants in the F1 generation (33) than the survivors generation (8) which increase the variation in the plants. To ensure that the mean of the F1 generation is not similar to the survivor population, the 95% confidence intervals were compared. The definition of similar or not similar is determined through 95% confidence intervals. The null hypothesis that is used to see if the survivors generation is similar to the F1 generation for is that there is no significant difference between the mean of the original population and the mean of the F1 generation.The SEM of the original population is 0.4492766416 and the SEM for the F1 generation is 0.3146201419. These SEM’s provide the range in which the confidence interval will range based on 5% built in error if the experiment was performed again. The upper and lower confidence intervals for the original survivor population is 14.78 and 12.98 respectively. The upper and lower confidence intervals for the F1 generation is 7.091361496 and 5.832880928 respectively. These confidence intervals do not overlap at any point in time which means that is a significant different between the mean of the survivor generation and the F1 generation. The null hypothesis failed to be rejected in this situation.

Figure 3

Discussion

Conclusions:

The results of the experiment does not support the research question because even though the means are different from each other, the mean of the  F1 generation is lower than the mean for the original population and the survivor parent population. If directional selection was inflicted on the parent population and affected the phenotypes of the offspring, we would expect for the  mean of the offspring to be greater than the original parent population and similar to the mean of the survivor parent population. We directionally selected for plants with average leaf lengths of 12mm and higher in which we wanted to have offspring with average leaf lengths of 12mm or larger but that was not the case. The average leaf lengths are instead smaller than the survivor parent population. The 95% confidence interval for the parent population is from 7.94 to 9.74 and the confidence interval for the F1 generation is from 5.83 to 7.09. The confidence intervals do not overlap which means that the means of the two populations are significantly different from each other. They are significantly different from each other in which the F1 generation has a lower mean than the parent population.  Through these comparisons, I can conclude that the research question was not fully supported by the experiment. After continually analysing the results of the experiment, I came to the conclusion that genetics did not have a role in this experiment but the results were rather an act of randomness. I had an outcome of what I wanted the outcome of the experiment to be and the results were not matching up. I wanted the mean of the F1 generation to similar to the mean of the survivors or even higher. In this experiment we were focused on phenotypes and genotypes so genetics was not a factor in this experiment in which genes of larger average leaves would not have passed down to the next generation. There were a couple limitations of the experiment. Specifically, one limitation would include that not all of the parent generation seeds grew into plants for the selection process to take place and to produce offspring. The seeds that did not bloom could have possibly had leaves of 12 mm or higher that could have affected the results of the experiment in some way.

Experimental Evaluation:

I do not feel 100% confident in the results I obtained because we only did one trial of the experiment. Performing multiple trials of the same experiment can confirm or refute the results obtain in the first trial. Performing multiple trials solidifies your experiment and an average of some sort can be calculated to incorporated all the results of each trial. Looking back on the lab, I would have been more organized in my notes and data. Many times throughout the experiment there was confusion on what day of the experiment we were on and there was confusion on what data belonged to which plant. At times there was a lot of confusion but as the experiment went on, it became easier to anticipate what we were doing. I do not believe there were any intentional human errors in this lab. The class followed the procedure to the experiment very well. Any sources of error in this lab comes from random errors. When planting the send and growing the parent generation, an error in planting the seeds, like forgetting fertilizer, could affect the growth of the plant which could affect the results of the experiment. Another source of error would be not keeping the plants hydrated at all times. Sometimes the water reservoir was not seeping up water through the cloth to be pulled up to the plant through the time. Many times we found our plants dry and hard. This characteristic of the soil of the plant could also affect growth and development and reproduction. Lastly, another source of error could have derived from measuring, Many times, it was difficult and very tedious to measure each leaves length. Error in measurement could have affected the selection and the over results of the experiment. I do not have any changes or improvements to make for this lab. The only thing I would do different is to just perform this experiment without the distractions of any other activities. In class, a lot of time was spent on other activities focused on other parts of the curriculum. Many time the students of the class forgot about the plants are lost track of the step of the procedure we were on. This is another potential error source that I would want to eliminate if I were to perform this experiment again.